WP Front Range Dental

Ageing affects the proliferation and mineralization of rat dental pulp stem cells under inflammatory conditions

Wed, 18 Sep 2019 02:48:37 -0700

Abstract

Aim

To comparatively evaluate changes in the proliferation and mineralization abilities of dental pulp stem cells (DPSCs) from juvenile and adult rats in a lipopolysaccharide (LPS)‐induced inflammatory microenvironment to provide a theoretical basis for the age‐related differences observed in DPSCs during repair of inflammatory injuries.

Methodology

DPSCs were isolated from juvenile (JDPSCs) and adult rats (ADPSCs), and senescence‐associated β‐galactosidase staining was used to compare senescence between JDPSCs and ADPSCs. Effects of LPS on JDPSCs and ADPSCs proliferation were investigated by cell counting kit‐8 assays and flow cytometry. Alizarin red staining, quantitative reverse transcription polymerase chain reaction and Western blot assay were used to examine the effects of LPS on mineralization‐related genes and proteins in JDPSCs and ADPSCs. Immunohistochemistry was used to compare interleukin‐1β (IL‐1β) and osteocalcin (OCN) expression in the pulpitis model. Unpaired Student's t‐tests and one‐way anova were used for statistical analysis.

Results

DPSCs were isolated from juvenile and adult rat dental pulp tissues. At low concentrations (0.1–1 μg mL⁻¹), LPS significantly promoted the proliferation of JDPSCs (P < 0.01) and ADPSCs (P < 0.01 or P < 0.05), with the effect being stronger in JDPSCs than in ADPSCs. In addition, mineralized nodules and the expression of mineralization‐related genes (OCN, DSPP, ALP, BSP) increased significantly after stimulation with LPS (0.5 μg mL⁻¹) in JDPSCs and ADPSCs (P < 0.01 or P < 0.05), and JDPSCs displayed a more obvious increase than ADPSCs. Western blots revealed OCN and ALP expression levels in JDPSCs treated with LPS were significantly upregulated (P < 0.05); meanwhile, ALP expression in ADPSCs increased slightly but significantly (P < 0.05), and OCN expression was not affected. Finally, IL‐1β expression was significantly higher (P < 0.05) and OCN expression was significantly lower (P < 0.05) in the inflamed dental pulp of adult rats than in juvenile rats.

Conclusions

A certain degree of inflammatory stimulation promoted the proliferation and mineralization of DPSCs; however, this effect declined with age. The DPSCs of adult donors in an inflammatory microenvironment have a weaker repair ability than that of juvenile donors, who are better candidates for tissues damage repair.

The most significant warning signs of sex trafficking include the presence of visible injuries in the #mouth. Renee Dixon explains what to look for and how dental professionals can help save victims’ lives. #dental #dentistry https://buff.ly/2StpOFI pic.

Mon, 16 Sep 2019 16:38:02 -0700

The most significant warning signs of sex trafficking include the presence of visible injuries in the #mouth. Renee Dixon explains what to look for and how dental professionals can help save victims’ lives. #dental #dentistry https://buff.ly/2StpOFI pic.twitter.com/ISsROr3qoS

#Dental coding is tricky. That's why Kyle Summerford shares #coding tips every month in the latest isc Dental Office Manager Digest. Learn about D4249—Clinical crown lengthening, hard tissue here. #dentistry https://buff.ly/2O5TPeo pic.twitter.com/AehGwQ

Mon, 16 Sep 2019 12:15:10 -0700

#Dental coding is tricky. That's why Kyle Summerford shares #coding tips every month in the latest isc Dental Office Manager Digest. Learn about D4249—Clinical crown lengthening, hard tissue here. #dentistry https://buff.ly/2O5TPeo pic.twitter.com/AehGwQRPam

#Dental assistants take care of many things around the practice to help days run smoothly. Here's a list to keep track of those many #responsibility. Add this to your collection of FREE downloadable dental forms from DIQ. #dentistry https://buff.ly/2LU

Mon, 16 Sep 2019 11:33:02 -0700

#Dental assistants take care of many things around the practice to help days run smoothly. Here's a list to keep track of those many #responsibility. Add this to your collection of FREE downloadable dental forms from DIQ. #dentistry https://buff.ly/2LUNpMx pic.twitter.com/RBKT5fGlua

The #struggle is real. How to solve bickering between #dental assistants & hygienists. This hygienist is tired of #jealous coworkers, derogatory comments, & staff fighting. What can she do to improve the situation? #dentistry https://buff.ly/2ZF0TVL pic.

Sun, 15 Sep 2019 13:30:06 -0700

The #struggle is real. How to solve bickering between #dental assistants & hygienists. This hygienist is tired of #jealous coworkers, derogatory comments, & staff fighting. What can she do to improve the situation? #dentistry https://buff.ly/2ZF0TVL pic.twitter.com/K9MGG6w7dK

Dr. Scott Froum addresses 5 of the most common #Questions #dental patients ask about pathology in the #mouth, and how to answer them. #dentistry https://buff.ly/2ZZkXD9 pic.twitter.com/SNwaqsLt4E

Sat, 14 Sep 2019 12:50:02 -0700

Dr. Scott Froum addresses 5 of the most common #Questions #dental patients ask about pathology in the #mouth, and how to answer them. #dentistry https://buff.ly/2ZZkXD9 pic.twitter.com/SNwaqsLt4E

Xerostomia affects up to 65% of #dental patients, but many don't mention their dry mouth because they accept it as a part of life. Learn how dental pros can help them. #dentistry https://buff.ly/2XDzSAN pic.twitter.com/vqTV7sHZ68

Fri, 13 Sep 2019 13:45:02 -0700

Xerostomia affects up to 65% of #dental patients, but many don't mention their dry mouth because they accept it as a part of life. Learn how dental pros can help them. #dentistry https://buff.ly/2XDzSAN pic.twitter.com/vqTV7sHZ68

This #dental front office person is wondering why she has to wear hose under her cropped pants to work. Is it really necessary? Her employer tells her it's @OSHA_DOL rules. But, really? #dentistry #officeattire https://buff.ly/32IwrHQ pic.twitter.com/xnD

Fri, 13 Sep 2019 11:38:01 -0700

This #dental front office person is wondering why she has to wear hose under her cropped pants to work. Is it really necessary? Her employer tells her it's @OSHA_DOL rules. But, really? #dentistry #officeattire https://buff.ly/32IwrHQ pic.twitter.com/xnDMuMceNm

Glossary for systematic reviews and meta‐analyses

Fri, 13 Sep 2019 09:47:51 -0700

Abstract

A systematic review aims to answer a focussed research question through a structured review of the evidence, using a predefined methodology, which often includes a meta‐analysis. A meta‐analysis is a statistical method used to combine the effect estimates from the individual studies included in a systematic review. Systematic reviews and meta‐analyses are positioned at the highest level in the hierarchy of clinical evidence. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) statement was introduced in 2009 to help authors improve the quality and reliability of systematic reviews and meta‐analyses. Recently, the volume of systematic reviews and meta‐analyses in the field of Endodontology has increased; however, the quality of the published manuscripts has been reported to be sub‐optimal, which does not take account of the systematic reviews that were rejected because of more obvious deficiencies. The aim of this paper is to present a comprehensive glossary of terminology commonly used in systematic reviews and meta‐analyses in an attempt to provide easily understood definitions and explanations to assist authors when reporting systematic reviews and meta‐analyses, and to allow those wishing to read them to become better informed.

Technological advancements & increased bone graft osteoblastic activity with growth-stimulating factors enable access to difficult furcal defects & allow bacterial detoxification, enabling #dental clinicians to save #molars once planned for extraction. h

Fri, 13 Sep 2019 09:11:01 -0700

Technological advancements & increased bone graft osteoblastic activity with growth-stimulating factors enable access to difficult furcal defects & allow bacterial detoxification, enabling #dental clinicians to save #molars once planned for extraction. https://buff.ly/31hUnSi pic.twitter.com/INCM14WQpT

Clinical applications, accuracy, and limitations of Guided Endodontics: a systematic review

Fri, 13 Sep 2019 07:38:53 -0700

Abstract

Background

The novel concept of guided endodontics has been reported as an effective method to obtain safe and reliable results in endodontic treatment.

Aim

To evaluate by means of a systematic review the clinical applications, accuracy and limitations of guided endodontic treatment.

Data sources

A search of the literature was performed on PubMed, EMBASE, Web of Science and Cochrane Library databases, until April 25^th, 2019. No language or year restrictions were applied.

Study eligibility criteria

Articles that answered the research question, including case reports, in vitro and ex vivo studies were included. Data extraction was performed independently by two reviewers.

Study appraisal

Quality assessment was done with STROBE, CARE and Modified CONSORT guidelines for observational, case reports and preclinical studies, respectively.

Results

A total of 22 articles including fifteen case reports, six pre‐clinical studies (in vitro and ex vivo studies), and one observational study, were included.

Limitations and Conclusions

Even though the level of evidence is low, and the methodology described among studies heterogeneous, all articles describe guided access cavity preparation and guided surgery as being highly accurate and successful techniques when comparing the drilled path to the planned treatment. More studies with a larger number of patients are necessary to obtain significant conclusions.

Coronal Root Canal Morphology of Permanent Two‐rooted Mandibular First Molars with Novel 3D Measurements

Fri, 13 Sep 2019 03:19:17 -0700

Abstract

Aim

To measure the coronal root canal morphology of permanent mandibular first molars using 3D coordinates for more precise conservative endodontic cavity preparation.

Methodology

In total 57 cone beam computed tomography (CBCT) images of the molars which had fully formed apices and sound structures without treatment were taken from 33 patients aged 16 to 75 years. The CBCT machine (MCT‐1[EX‐2F], J. Morita Manufacturing Corp, Kyoto, Japan) provided 14 ‐bit greyscale images with the voxel size of 0.125mm. All images were taken at 80 kV and 5.0 mA, with a 17‐second exposure time, which were then reconstructed in 3D models and viewed by an endodontist. The gender of the patients and the tooth position, and number of root canals, were recorded. The landmarks of coronal root canals were determined, then the distribution of landmarks, maximum curvature in the axial direction and curvature directions in the horizontal direction of coronal root canals were measured. Distributions of landmarks were analysed using a spatial statistics method. Data about curvature were compared using a t test.

Results

Overall, the distribution of root canal orifices and the centre of the canal primary curve were more centralized than other landmarks. The landmarks were located more mesiobuccally to the centre of the occlusal plane of mandibular first molars. Specifically, the measurements of the maximum curvature of coronal root canals in the axial direction were: in 3‐canal teeth, the average angles of curvatures were 22°,23°,15° for mesiobuccal (MB), mesiolingual (ML) and distobuccal (DB) canals, respectively; in 4‐canal teeth, the average angles of curvatures were 24°,26°,15°,22°for MB, ML , DB, and distolingual (DL) canals, respectively. The degrees of coronal root canal curvatures in the horizontal direction were: in 3‐canal teeth, the average angles of curvatures were ‐8°,47°,‐2° for MB, ML and DB canals, respectively; in 4‐canals teeth, the average angles were ‐11°,50°,‐28°,45° for MB, ML, DB, and DL canals, respectively. Statistically, there was no reliable side or sex difference in any of the measurements (p >0.05).

Conclusions

In permanent two‐rooted mandibular first molars, the coronal canals clustered in the direction of the mesiobuccal side of the occlusal surface of the teeth.

Does ultraconservative access affect the efficacy of root canal treatment and the fracture resistance of two‐rooted maxillary premolars?

Fri, 13 Sep 2019 03:13:38 -0700

Abstract

Aim

To evaluate the influence of ultraconservative endodontic cavities (UEC) on canal shaping and filling ability, cleaning of the pulp chamber, time required to perform root canal treatment and fracture resistance of 2‐rooted maxillary premolars in comparison to traditional endodontic access cavities (TEC) in extracted teeth placed in a phantom head to simulate clinical conditions..

Methodology

Twenty extracted intact 2‐rooted maxillary premolars were scanned in a micro‐computed tomographic device, matched based on similar anatomic features of the canals, and assigned to UEC or TEC groups (n=10). Then, teeth were mounted on a mannequin head and their pulp chamber accessed. After canal preparation, filling and cavity restoration, the time required to perform root canal treatment was recorded and the specimens were loaded to fracture in a universal testing machine. The maximum load at fracture were recorded. The sample was scanned after root canal instrumentation, filling and restoration procedures. Untouched canal areas, accumulation of hard‐tissue debris (AHTD), voids in root fillings and cleaning of the pulp chamber were analyzed. Data were analyzed statistically using Shapiro‐Wilk and Student's t‐tests with a significance level of 5%.

Results

The percentage of untouched canal area did not differ significantly between UEC and TEC groups (P>0.05). However, UECs were associated with a greater percentage of AHTD after canal preparation (P<0.05). No differences were observed in terms of voids in root fillings between the groups (P>0.05). Nonetheless, UEC had a greater percentage of root filling remnants in the pulp chamber after cleaning procedures (P<0.05). The time required to perform root canal treatment was significantly longer in the UEC group (P<0.05). There was no difference regarding the mean load at fracture between the groups (P>0.05). Unrestorable fractures were observed in all specimens of both groups.

Conclusions

There was no true benefit associated with ultraconservative endodontic cavities. UEC resulted in more AHTD remaining inside the root canals. UEC did not influence the quality of root fillings; however, UEC made the cleaning procedure of the pulp chamber more difficult, thus increasing the total time required to perform root canal treatment. Moreover, UEC were not associated with an increase in fracture resistance of root filled 2‐rooted maxillary premolars.

Self‐efficacy of undergraduate dental students in Endodontics within Aarhus and Amsterdam

Fri, 13 Sep 2019 03:13:21 -0700

Abstract

Aim

To understand whether the self‐efficacy of undergraduates is associated with the extent of the endodontic education they received.

Methodology

Data were obtained from three undergraduate endodontic programmes in two universities: Aarhus University (AU), Denmark and the Academic Centre for Dentistry Amsterdam (ACTA), the Netherlands. Close to their graduations in 2016 or 2017, students completed a questionnaire that contained the Endodontic General Self‐Efficacy Scale and questions on how they valued the education they received in Endodontics. The information on the number and type of root canal treatments participants had performed on patients was collected from dental clinic management systems. Data were analysed using non‐parametric tests and multiple regression analyses.

Results

The median number of treated root canals on patients per student was 5 in the standard programme at ACTA, 10 in AU, and 14.5 in the extended programme at ACTA. Students' self‐efficacy increased with the number of treated root canals, however, retreatments and root canal treatments in molars were negatively associated with self‐efficacy. All students wanted more experience in performing root canal treatment on patients.

Conclusions

The endodontic self‐efficacy of students from the standard programmes of the two participating universities was comparable. Students' self‐efficacy was influenced mostly by their clinical experience when performing root canal treatment. It seems that the more root canal treatments students perform on patients, the greater their self‐efficacy is at graduation. However, treating difficult cases (molars and retreatments) might reduce their self‐efficacy.

Latoya Blandin, RDH, a mother of 2 young children, shares how she survives (& thrives) as a working mom in the #dental hygiene operatory. She says: "#workingmoms, you have two jobs & they both require you to be efficient!" #dentistry #motherhood https://

Thu, 12 Sep 2019 16:20:02 -0700

Latoya Blandin, RDH, a mother of 2 young children, shares how she survives (& thrives) as a working mom in the #dental hygiene operatory. She says: " #workingmoms, you have two jobs & they both require you to be efficient!" #dentistry #motherhood https://buff.ly/30BqVqA pic.twitter.com/yALqoqft8e

It's becoming well known among #dental pros that they are contributing to the #opioid crisis. How can dental assistants play a role in changing patient dependence on these painkillers? #dentistry #addiction https://buff.ly/2ZhYcJx pic.twitter.com/SnXwTMd

Thu, 12 Sep 2019 12:10:03 -0700

It's becoming well known among #dental pros that they are contributing to the #opioid crisis. How can dental assistants play a role in changing patient dependence on these painkillers? #dentistry #addiction https://buff.ly/2ZhYcJx pic.twitter.com/SnXwTMdqRS

During the recent RDH Under One Roof 2019, Amber Auger, MPH, RDH, interviewed Leo Pranitis of @Prisyna about Moisyn, a product for dry mouth relief. Watch the video to learn more. #dental #oralhealth #dentistry https://buff.ly/2A9pcgb pic.twitter.com/ekA

Thu, 12 Sep 2019 08:36:01 -0700

During the recent RDH Under One Roof 2019, Amber Auger, MPH, RDH, interviewed Leo Pranitis of @Prisyna about Moisyn, a product for dry mouth relief. Watch the video to learn more. #dental #oralhealth #dentistry https://buff.ly/2A9pcgb pic.twitter.com/ekAPdz7cS7

Electric handpieces: Protecting your investment: handpiece repair technician Glenn Williams explains the proper way to maintain an electric handpiece to protect your investment & your patients. #dental #dentistry https://buff.ly/2UQZjLE pic.twitter.com/d

Wed, 11 Sep 2019 16:20:03 -0700

Electric handpieces: Protecting your investment: handpiece repair technician Glenn Williams explains the proper way to maintain an electric handpiece to protect your investment & your patients. #dental #dentistry https://buff.ly/2UQZjLE pic.twitter.com/dOzv3GknKA

Dr. Nancy Addy says #dentists who practice in the field of #dental #sleep medicine must be prepared for anything because every patient is unique. She shares examples of some very unusual custom oral appliances that she has encountered. #dentistry https:/

Wed, 11 Sep 2019 12:28:01 -0700

Dr. Nancy Addy says #dentists who practice in the field of #dental #sleep medicine must be prepared for anything because every patient is unique. She shares examples of some very unusual custom oral appliances that she has encountered. #dentistry https://buff.ly/2WjNH6T pic.twitter.com/2BxzuHlF3G

Anxious patients dread visiting the #dental practice—and you may dread seeing them, too. These strategies help make the appointment better for everyone. #dentistry #anxiety https://buff.ly/33NEZii pic.twitter.com/46kBiSdQ1D

Wed, 11 Sep 2019 08:26:04 -0700

Anxious patients dread visiting the #dental practice—and you may dread seeing them, too. These strategies help make the appointment better for everyone. #dentistry #anxiety https://buff.ly/33NEZii pic.twitter.com/46kBiSdQ1D

In the latest @dentaleconomic Recall Visit #video, Drs. Chris Salierno and Greg Winteregg discuss fee increases, accepting fewer low-fee plans, & still making a #profit. #dental #dentistry #insurance https://buff.ly/31hytyI pic.twitter.com/Y1niQAYoZI

Tue, 10 Sep 2019 16:40:01 -0700

In the latest @dentaleconomic Recall Visit #video, Drs. Chris Salierno and Greg Winteregg discuss fee increases, accepting fewer low-fee plans, & still making a #profit. #dental #dentistry #insurance https://buff.ly/31hytyI pic.twitter.com/Y1niQAYoZI

#vaping is on the rise. & is gaining popularity with young #dental patients who have never used nicotine before & are now trying flavored #ecigarettes What are its effects on the oral cavity? How can #dental professionals share this information? https://

Tue, 10 Sep 2019 12:10:02 -0700

#vaping is on the rise. & is gaining popularity with young #dental patients who have never used nicotine before & are now trying flavored #ecigarettes What are its effects on the oral cavity? How can #dental professionals share this information? https://buff.ly/2ZixehF pic.twitter.com/Cgcn3q1vSs

Bone tissue response to an MTA‐based endodontic sealer, and the effect of the addition of calcium aluminate and silver particles

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To evaluate bone tissue reactions in rats to an MTA‐based endodontic sealer with and without the addition of various concentrations of C3A or C3A + Ag.

Methodology

Bone tissue reactions were evaluated in 45 Wistar rats after 7, 30 and 90 days (n = 5 per period). Three surgical cavities were prepared on the right femur and filled with 0.2 mL MTA Fillapex, MTA Fillapex + C3A and C3A + Ag at various concentrations: AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany), EndoSequence BC (Brasseler USA, Savannah, GA, USA) or no sealer (negative control). By the end of each experimental period, animals were randomly euthanized. The samples were histologically processed and analysed using a light microscope. The presence of inflammatory cells, fibres and hard tissue barrier formation was evaluated. Data were analysed statistically using nonparametric tests to compare the differences between groups. Multiple groups were compared using the Kruskal–Wallis and Mann–Whitney U‐tests with a Bonferroni correction at P = 0.05.

Results

The inflammatory response significantly decreased from 30 to 90 days (P < 0.05). Fibre condensation was similar amongst the groups at 07 and 30 days after intervention (P > 0.05). At 90 days, however, fibres were absent in most specimens of EndoSequence BC Sealer, AH Plus, MTA Fillapex and the control group, whilst they were still observed in samples of the modified sealers (P < 0.05). At 90 days, all specimens of AH Plus, EndoSequence BC Sealer and control group had complete formation of hard tissue barrier. In the MTA Fillapex group, as well as in the modified sealers groups, partial deposition of mineralized tissue was noticed.

Conclusion

The hypothesis tested that the incorporation of C3A and C3A + Ag particles to MTA Fillapex would improve bone tissue repair was partially accepted, since modified MTA Fillapex did not have the same repair potential as the commercial bioceramic material.

Effect of ethylenediaminetetraacetic acid irrigation on immune‐inflammatory response in teeth submitted to regenerative endodontic therapy

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To analyse longitudinally the immune‐inflammatory response in teeth of mice that underwent a regenerative protocol with or without the use of ethylenediaminetetraacetic acid (EDTA) to irrigate the root canal system.

Methodology

First maxillary molars of mice were devitalized using size 10 and 15 files. Teeth were divided into the following groups: Empty – the canals were left empty; Blood Clot (BC) – the canals were filled with a blood clot; and EDTA + Blood – the canals were irrigated with 0.06 mL of 17% EDTA for 1 min and filled with a blood clot. Access cavities were restored with Coltosol^®. Animals were sacrificed at 7, 14 or 21 days after the operative procedures, and teeth were collected. RNA was extracted, mRNA expression of the cytokines IGF, NGF, IL‐1α, IL‐10, TGF and VEGF was assessed using real‐time PCR, and the anova Kruskal–Wallis test was used.

Results

IL‐1 mRNA expression was significantly higher in the EDTA + BC group than in the Empty and BC groups at the 7th and 14th days of evaluation (P < 0.05). IL‐10 mRNA expression was similar across the three groups at all time periods. TGF‐β mRNA expression in the EDTA + BC group was significantly higher on the 7th and 21st days than on the 14th (P < 0.05); at day 21, TGF‐β mRNA expression was similar between the BC and EDTA + BC groups but significantly higher than in the Empty group (P < 0.05). IGF mRNA expression was significantly higher in the EDTA + BC group than in the other groups at all time periods. VEGF mRNA expression remained unchanged throughout the experimental period in all groups (P > 0.05). NGF mRNA expression was similar amongst all groups at the 7th and 21st days (P > 0.05). At the 14th day, however, there was a significant increase in NGF mRNA expression in the EDTA + Blood group (P < 0.05) when compared with the expression in the other groups.

Conclusion

EDTA promoted increased expression of factors that have the potential to improve the outcome of regenerative endodontic treatment.

Root canal configuration and its relation with endodontic technical errors in premolar teeth: a CBCT analysis

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To evaluate the association between endodontic technical errors and the root canal configuration (RCC) of human premolars, as well as their relationship with periapical lesions through cone‐beam computed tomography (CBCT) images.

Methodology

The sample consisted of CBCT scans belonging to 136 patients, totalling 152 root filled premolars (185 roots). CBCT images were evaluated by two oral radiologists. RCC was recorded according to Vertucci's classification, and the endodontic treatment quality was judged on the presence and type of technical endodontic errors (underfilling, overfilling, nonhomogeneous filling, nonfilled canal, fractured instruments, root deviation and absence of coronal restoration). In addition, the presence of periapical lesions associated with each RCC was recorded. Data were expressed by frequencies and percentages, and intraobserver agreement was calculated using the Kappa test.

Results

The most common RCC was type I (71%), followed by type IV (15%), type II (8%), type V (3%), type VI (1%) and type III (1%). Types VII and VIII were not observed in the sample. Underfilling was the most frequent endodontic technical error for most RCCs, except for types IV, V and ‘other’, whose most frequent error was a nonfilled canal. The presence of technical errors was greater with an increase in the proportion of the periapical lesions. The intraobserver agreement was excellent.

Conclusions

There was an increase in the prevalence of endodontic technical errors and in the presence of periapical lesions as the anatomical complexity of the root canals increased. Underfilled and nonfilled canal were the most frequent endodontic technical errors.

TLR5 activation induces expression of the pro‐inflammatory mediator Urokinase Plasminogen Activator via NF‐κB and MAPK signalling pathways in human dental pulp cells

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To explore the involvement of TLR5 in pulp inflammation and to examine the effects of TLR5 activation with its ligand, FlaB protein, on pro‐inflammatory gene expression.

Methodology

TLR5 expression in dental pulp tissues and human dental pulp cells (hDPCs) were determined by immunohistochemistry, immunocytochemistry, Western blots and RT‐PCR analyses. To examine the role of TLR5, hDPCs were treated with recombinant FlaB protein (500 ng mL⁻¹) to activate the receptor or with a small interfering RNA against TLR5 (si‐TLR5) to downregulate the receptor. After exposure to FlaB, the expression of inflammation‐related proteins was screened using a protein array kit. Western blots or qRT‐PCR analyses were performed to identify changes in the expression of uPA (urokinase plasminogen activator), TIMPs (tissue inhibitor of metalloproteinases), and IL‐6 and to determine their signalling pathways. Statistical analysis was performed using one‐way analysis of variance (anova) with Tukey post hoc test; P < 0.05 was considered statistically significant.

Result

TLR5 expression was identified in pulp tissues and hDPCs. In the protein array analysis, treatment with FlaB significantly increased uPA expression (P < 0.01) and significantly decreased TIMP1/4 (P < 0.05). FlaB treatment also significantly increased expression of the inflammatory marker IL‐6 (P < 0.01). FlaB treatment increased phosphorylation of the NF‐κB p65 subunit, JNK, p38 and ERK. Chemical inhibitors of NF‐κB (Bay11‐7082), p38 (SB202190) or ERK (U0126) decreased the FlaB induction of uPA expression. Downregulation of TLR5 expression by siRNA decreased the FlaB induction of uPA protein and p65 phosphorylation.

Conclusion

TLR5 activation with FlaB treatment induced the expression of uPA via the NF‐κB and MAPK signalling pathways. Flagellin‐bearing oral bacteria may cause pulp inflammation through TLR5. The findings provide new clues to control pulpal diseases by targeting TLR5 signalling pathways.

Anatomical danger zone reconsidered: a micro‐CT study on dentine thickness in mandibular molars

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To investigate the smallest dentine thickness in mesial canals of mandibular molars along the cervical and middle thirds of the root by means of a micro‐computed tomographic (micro‐CT) technology and digital image analysis.

Methodology

Fifty mesial roots of mandibular molars having two independent canals (mesiobuccal and mesiolingual), in the coronal and middle levels, were selected and scanned in a micro‐CT device. After reconstruction procedures, approximately 468 slices per root covering the 7 mm below the furcation area of the mesial root were analysed to measure the smallest dentine thickness (danger zone [DZ]) in each slice from both distal and mesial regions of the mesial canals by an automatic segmentation process.

Results

The DZ values in the mesiobuccal canals varied from 0.67 to 1.93 mm, with an average of 1.13 ± 0.21 mm. For the mesiolingual canals, the DZ varied from 0.77 to 1.89 mm with an average of 1.10 ± 0.21 mm. There was no correspondence in the DZ between the mesiobuccal and mesiolingual canals at the same cross‐sectional level in 71% of the specimens. Moreover, the smallest dentine thickness was towards the mesial region of the roots in 22% and 18% of the mesiolingual and mesiobuccal canals, respectively. (Figs 1 and 2

Conclusions

The smallest dentine thickness was on the mesial plane of the roots in about 40% of the canals. The vertical location of the DZ in relation to the furcation area was in the middle third of the root.

Validation of the effectiveness of the Dental Practicality Index in predicting the outcome of root canal retreatments

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To assess the effectiveness of the Dental Practicality Index (DPI) in predicting the outcome of root canal retreatment in posterior teeth.

Methodology

One hundred and thirty‐seven posterior teeth with symptoms and/or signs of post‐treatment endodontic disease requiring root canal retreatment and previously included in a clinical trial were selected. Clinical and radiographic examinations including digital periapical and cone beam computed tomography (CBCT) were obtained pre‐treatment and 1‐year postoperatively from a previous study. Two calibrated and trained assessors who were unaware of the treatment outcome assessed the pre‐treatment clinical records of these cases using the DPI. The DPI score was then compared to the outcome of the root canal retreatment. A Chi‐square/Fisher’s exact test was used to establish a relationship between categorical variables, the total score of DPI vs outcome.

Results

Retreated teeth with DPI scores equal to 6 or above had an unfavourable outcome of 50% vs 14% of teeth with DPI below 6. Teeth with DPI score equal to 3 or above had an unfavourable outcome of 23% versus 2%, for teeth below 3. Molar teeth with a DPI score below 3 had a favourable outcome percentage of 96%.

Conclusions

This study highlighted that using the DPI gave a good outcome prediction for root canal retreatments. However, further research, including the prospective assessment of a wider range of cases undertaken by a larger group of examiners is needed to further validate the DPI.

Impact of systemic diseases and tooth‐based factors on outcome of root canal treatment

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To investigate the impact of systemic health and tooth‐based factors on the outcome of root canal treatment (RCT).

Methodology

The target population consisted of all patients receiving RCT at the Helsinki University Clinic in 2008–2011. The inclusion criteria were diagnosable pre‐ and postoperative (minimum 6 months after root filling) radiographs and adequate patient records of RCT available. Teeth extracted for nonendodontic reasons were excluded. Patient documents including digital radiographs of 640 permanent teeth in 504 patients were scrutinized. The radiographs were assessed by two examiners under standardized conditions. The Periapical Index was used to define radiographically ‘healthy’ and ‘healing’ cases as successful. Data included systemic health, technical quality of root fillings, type of restoration and level of alveolar bone loss. Statistical evaluation of differences between groups included chi‐squared tests and Fisher's exact tests. Logistic regression modelling utilizing robust standard errors to allow for clustering within patients was applied to analyse factors related to the outcome of RCT.

Results

The mean age of patients was 51.5 years (standard deviation (SD) 15.0; range 10–83), and 49% were female. In 41 cases (6%), the patient had diabetes mellitus (DM), in 132 (21%) cardiovascular disease and in 284 (44%) no systemic disease. The follow‐up period was 6–71 months (mean 22.7). In the primary analyses, the success rate of RCT was 73.2% in DM patients and 85.6% in patients with no systemic disease (P = 0.043); other systemic diseases had no impact on success. In the multifactorial analysis, the impact of DM became nonsignificant and RCTs were more likely to succeed in the absence of apical periodontitis (AP; odds ratio (OR) = 4.4; P < 0.001), in teeth with optimal root filling quality (OR = 2.5; P < 0.001), in teeth restored with indirect restorations (OR = 3.7; P = 0.002) and in teeth with none/mild alveolar bone loss (OR = 2.4; P = 0.003).

Conclusions

DM diminished the success of RCT, especially in teeth with apical periodontitis. However, tooth‐based factors had a more profound impact on the outcome of RCT. This should be considered in clinical decision‐making and in assessment of RCT prognosis.

‘Seeing is believing’: a qualitative approach to studying the use of cone beam computed tomography in endodontics in Sweden

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To gain insight into the decision processes of dentists when requesting a cone beam computed tomography (CBCT) examination in endodontic settings.

Methodology

Fourteen dentists (eight female) 33–58 years of age (mean = 44) practising in Sweden were interviewed. Ten of the dentists were specialists in Endodontics. The absolute inclusion criterion was experience of referring patients for CBCT for endodontic reasons. The included dentists comprised a strategically selected diverse sample in terms of gender, age, work experience, educational background, location of practice, service affiliation and accessibility to CBCT. Data were obtained through semistructured interviews exposing the context of their last three self‐reported referrals. Dentists were encouraged to describe their experiences of the circumstances in their own words, aided by the interviewer's open‐ended questions. The interviews were audio‐recorded and transcribed verbatim. The text was analysed by qualitative content analysis.

Results

The manifest content was organized into three categories that were defined as visualization as a desire, facilitating tough decisions and allocating responsibility.

Conclusion

An overall theme (covering the latent content) was identified: A balance between clinical common sense and a ‘better safe than sorry’ attitude guides the use of CBCT in endodontic settings. Informants had high clinical standards, knowledge concerning radiation risks and good sense, which could compensate for their lack of knowledge of guidelines. The national radiation regulatory system was perceived to work as a slightly porous gatekeeper for over‐usage.

Histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis of tissue response to sealing materials after furcation perforation

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To evaluate in vivo tissue responses after sealing furcation perforations in dog's teeth with either Biodentine™, mineral trioxide aggregate (MTA) or gutta‐percha, by means of histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis.

Methodology

After root canal treatment, perforations were created in the central region of the pulp chamber floor using a round diamond bur and filled with one or other of the materials. The animals were euthanized after 120 days, and the teeth (n = 30) were processed for histopathological analysis of new mineralized tissue formation and collagen fibre reinsertion, immunohistochemical analysis of osteopontin (OPN) and alkaline phosphatase (ALP) and immunofluorescence analysis for bone morphogenetic protein (BMP‐2), cementum attachment protein (CAP), bone sialoprotein (BSP), osteocalcin (OCN) and cementum protein1 (CEMP1). Histoenzymology was performed for TRAP activity and osteoclast count. Data were analysed statistically (α = 0.05) using chi‐square and Kruskal–Wallis tests.

Results

Gutta‐percha did not induce mineralized tissue formation. MTA and Biodentine^TM formed mineralized tissue in 88% and 92% of specimens, respectively, with no significant difference (P > 0.05). Gutta‐percha was associated with scattered collagen fibres parallel to the perforations. Groups treated with MTA or Biodentine^TM had partial fibre reinsertion perpendicular to the newly formed mineralized tissue. All materials induced OPN and ALP expression, weakest for gutta‐percha and strongest for MTA (P < 0.05). Only MTA induced BMP‐2, BSP, OCN, CAP and CEMP1 expression. Osteoclast counts were similar in all groups (P = 0.97).

Conclusions

Mineral trioxide aggregate and Biodentine^TM were biocompatible, with formation of mineralized tissue and partial reinsertion of collagen fibres. In addition, the participation of several molecules by which calcium silicate‐based materials induce the formation of mineralized tissue were noted, with expression of ALP and OPN mineralization markers, without interference in the number of osteoclasts. Only MTA stimulated the expression of proteins associated with the formation of a cementum‐like mineralized tissue.

Anti‐inflammatory and antiresorptive functions of melatonin on experimentally induced periapical lesions

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To investigate the effects of systemically administered melatonin on inflammation and alveolar bone resorption in rats with experimentally induced periapical lesions.

Methodology

Thirty adult Sprague Dawley rats were divided equally into negative, positive control and melatonin groups. The pulp chambers of their mandibular first molars were exposed to the oral environment to induce experimental periapical lesions in the positive control and melatonin groups. The melatonin group received daily intraperitoneal injections of melatonin at a dose of 10 mg kg⁻¹. After 21 days, the animals were euthanized; the hemi‐mandible parts were prepared for radiological, histopathological, immunohistochemical (IL‐1β, RANK, RANKL, OPG and tartrate‐resistant acid phosphatase (TRAP) and Brown–Brenn (bacteria) evaluations. Data were analysed by Kruskal–Wallis (for non‐parametric data) and one‐way anova tests (for parametric data) (P < 0.05).

Results

The area of radiographic periapical bone loss was significantly smaller in rats that were given daily intraperitoneal injections of melatonin (P < 0.01). The histopathological scores of the melatonin group were significantly lower than those of positive control group (P < 0.01). Histomorphometrically, the area of periapical bone loss in the melatonin group was significantly smaller than the positive control group (P < 0.01). The expression of IL1‐β, RANK and RANKL was significantly higher in the positive control group, whereas OPG was significantly higher in the melatonin group (P < 0.01). The number of osteoclasts was significantly greater in the positive control group by TRAP staining analyses (P < 0.01). The scores for bacteria localization using Brown–Brenn staining in the melatonin group was significantly lower than that of the positive control group (P < 0.01).

Conclusions

Melatonin demonstrated antiresorptive effects on bone associated with experimentally induced periapical lesions in rats via its anti‐inflammatory activity. Further studies are necessary to evaluate its possible effects on the healing of periapical lesions.

Biomechanical performance of an immature maxillary central incisor after revitalization: a finite element analysis

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

Aim

To investigate the stress distribution in an immature maxillary incisor and the same tooth after simulated revitalization with deposition of tubular dentine or cementum by finite element analysis (FEA).

Methodology

A finite element model of a maxillary central incisor was developed on the basis of a µCT scan. The tooth was segmented in two parts: a part that represented a tooth in an immature state and an apical part that represented the tissue formed after revitalization. The apical part was given the mechanical properties of dentine or cementum. The immature tooth and the same tooth reinforced by either dentine or cementum underwent simulation of biting, trauma and orthodontic movement. Von Mises stress values were compared between the scenarios and tooth segments.

Results

Maximum stress in the immature incisor developed apically; however, dentine‐ and cementum‐reinforced teeth revealed the greatest stress in the external portion of the root decreasing towards the apex. Greatest mechanical stress was caused by dental trauma perpendicular to the long axis of the root followed by biting and orthodontic movement. Stress peaks were lower in the dentine‐reinforced tooth compared with the cementum‐reinforced tooth in all scenarios; however, median stress in the immature part was reduced irrespective of dentine or cementum deposition. Dentine reinforcement caused greater stress values in the apical segment due to absorbance of the applied force, whereas stress was not transferred towards deposited cementum.

Conclusions

Apposition of simulated hard tissue in a maxillary central incisor after revitalization reduced mechanical stress in the immature tooth. Formation of dentine was advantageous because, unlike cementum, it facilitated an even stress distribution throughout the root resulting in lower stress values.

Research that matters: studies on fatigue of rotary and reciprocating NiTi root canal instruments

Tue, 10 Sep 2019 11:19:33 -0700

International Endodontic Journal, Volume 52, Issue 10, Page 1401-1402, October 2019.

Issue Information

Tue, 10 Sep 2019 11:19:33 -0700

International Endodontic Journal, Volume 52, Issue 10, Page 1399-1399, October 2019.

Corrigendum

Tue, 10 Sep 2019 11:19:33 -0700

International Endodontic Journal, Volume 52, Issue 10, Page 1529-1529, October 2019.

A critical appraisal of studies on cyclic fatigue resistance of engine‐driven endodontic instruments

Tue, 10 Sep 2019 11:19:33 -0700

Abstract

The endodontic literature contains a plethora of studies on static and dynamic cyclic fatigue resistance tests performed on a large array of rotary or reciprocating nickel–titanium endodontic instruments. It was the aim of this review to summarize the currently available evidence to point out the different outcomes from static versus dynamic tests and to assess whether cyclic fatigue tests provide useful data and information for clinical practice. An electronic literature research in the database PubMed was performed using appropriate search terms, and the titles and abstract were screened for relevance. Language was restricted to English. The review reveals marked differences between the results obtained in static and dynamic tests, and also, the results for the same instruments assessed either under static or dynamic experimental conditions are widely inconsistent. Between the lowest and the highest value for one and the same pathfinding instrument was a factor of about 123 when cyclic fatigue was assessed either under static or dynamic experimental conditions. Moreover, standard deviations of up to 30% have been reported. Environmental temperature has a 500% impact on the lifetime of instruments. In conclusion, fatigue resistance tests conducted under room temperature should be regarded as having little meaning and the scientific and clinical benefits of fatigue resistance tests are very limited. These data should be provided by the manufacturer of the instruments.

#Dentsts: Critiquing your #dental team members is not easy. But as the team leader, these conversations will be necessary. Dr. Chris Salierno says to remember to use positive feedback as well, which leads to better learning. #dentistry https://buff.ly/2Z

Tue, 10 Sep 2019 09:08:03 -0700

#Dentsts: Critiquing your #dental team members is not easy. But as the team leader, these conversations will be necessary. Dr. Chris Salierno says to remember to use positive feedback as well, which leads to better learning. #dentistry https://buff.ly/2ZO2f12 pic.twitter.com/RBsYE4zm4Q

#Dentists: Here's a question for you. Would you play top dollar for your own #dental practice? See how failing to address an exit plans can make the difference between retiring on your terms or having to make big lifestyle reductions when you #retire. h

Mon, 09 Sep 2019 17:00:03 -0700

#Dentists: Here's a question for you. Would you play top dollar for your own #dental practice? See how failing to address an exit plans can make the difference between retiring on your terms or having to make big lifestyle reductions when you #retire. https://buff.ly/2IbFklN pic.twitter.com/EbWVdsC9v4

The #mouth ages, too. Polyphenols, long associated with expensive skin creams, hold promise as an excellent oral health adjunct, particularly for the prevention of root caries. #dental #dentistry #oralhealth https://buff.ly/2A200I6 pic.twitter.com/PwnDft

Mon, 09 Sep 2019 12:25:02 -0700

The #mouth ages, too. Polyphenols, long associated with expensive skin creams, hold promise as an excellent oral health adjunct, particularly for the prevention of root caries. #dental #dentistry #oralhealth https://buff.ly/2A200I6 pic.twitter.com/PwnDftaKEn

According to research done by the Business Insider, #dental hygiene is considered the number one most “unhealthy” career. Here's why #massage therapy is a necessity in the hygienist’s #selfcare regimen. #dentistry https://buff.ly/2Z9Ley9 pic.twitter.com/

Mon, 09 Sep 2019 08:44:22 -0700

According to research done by the Business Insider, #dental hygiene is considered the number one most “unhealthy” career. Here's why #massage therapy is a necessity in the hygienist’s #selfcare regimen. #dentistry https://buff.ly/2Z9Ley9 pic.twitter.com/yTfBaGZ88g

Comparing the anaesthetic efficacy of articaine with lidocaine in patients with irreversible pulpitis: An umbrella review

Fri, 06 Sep 2019 11:13:06 -0700

Abstract

Background

Pain management can be challenging during root canal treatment of teeth with irreversible pulpitis.

Aim

To identify whether articaine or lidocaine is the most appropriate local anaesthetic solution for teeth with irreversible pulpitis undergoing root canal treatment.

Data source

The protocol of this umbrella review is registered in the PROSPERO database (CRD42019137624). PubMed, EBSCHO host and Scopus databases were searched until June 2019.

Study eligibility criteria, participants, and interventions

Systematic reviews published in English comparing the effectiveness of local anaesthesia following administration of articaine or lidocaine in patients undergoing root canal treatment of teeth diagnosed with irreversible pulpitis were included. Two independent reviewers selected the studies, carried out the data extraction and the appraisal of the included reviews. Disagreements were resolved in consultation with a third reviewer.

Study appraisal and synthesis methods

The quality of the included reviews was appraised by two independent reviewers using the AMSTAR tool (A measurement tool to assess systematic reviews). Each of the 11 AMSTAR items, was given a score of 1 if the specific criterion was met, or 0 if the criterion was not met or the information was unclear.

Results

Five systematic reviews with meta‐analyses were included. The AMSTAR score for the reviews ranged from 8‐11, out of a maximum score of 11, and all reviews were categorized as “high” quality. Two reviews scored 0 for item 8 in AMSTAR because the scientific quality of the clinical trials included in these reviews was not used in the formulation of the conclusions.

Limitations

Systematic reviews published only in English language were included. Only a small number of studies were available to assess pain intensity during the injection phase, the time until the onset of anaesthesia and the occurrence of adverse events.

Conclusions and implications of key findings

Articaine is more effective than lidocaine for local anaesthesia of teeth with irreversible pulpitis undergoing root canal treatment. There is limited evidence that injection of articaine is less painful, has more rapid onset and has fewer adverse events compared with lidocaine.

Mechanical properties and metallurgical features of new and ex vivo used reciproc blue and reciproc

Thu, 05 Sep 2019 11:57:41 -0700

Abstract

Aim

To compare the mechanical properties and metallurgic features of new and used Reciproc Blue and Reciproc instruments.

Methodology

A total of 120 R25Reciproc Blue and R25 Reciproc instruments were used. The morphological, chemical, mechanical, thermal and phase composition characteristics of new and ex vivo used files were investigated by scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy (EDS), focused ions beam analysis (FIB), micro‐Raman spectroscopy, optical and SEM metallography, X‐ray diffraction (XRD), differential scanning calorimetry (DSC) and indentation tests. Usage‐induce degradation was evaluated. Ten new and ten used instruments per type were run until fracture occurred in a stainless‐steel artificial canal (60° angle of curvature, 4‐mm radius). Time to fracture and the length of the fractured fragment were recorded. Torque and angle of rotation at failure of ten new and ten used instruments for each type were measured according to ISO 3630‐1. The fracture surface of each fragment was examined. Analyses of variance and Bonferroni post hoc tests were used to analyse the data statistically (α‐level 0.05).

Results

SEM analysis revealed microcracks near the tip on both files after ex vivo usage tests. FIB imaging and micro‐Raman spectroscopy confirmed the presence of an oxide layer on the Reciproc Blue surface. There was no thinning of the coating after use. The area of grains of Reciproc detected by metallographic analysis was significantly wider than Reciproc Blue (P<0.05). XRD revealed a reduction of martensite and R‐phase in Reciproc Blue after use. DSC analysis revealed different transformation temperatures for the instruments analysed. Reciproc Blue was significantly more flexible than Reciproc for both new and used samples (P<0.05) and they were significantly more resistant to cyclic fatigue than Reciproc (P<0.05). Ex vivo usage reduced the fatigue resistance of both files. Torsional resistance of Reciproc and Reciproc blue was not reduced by the simulated use (P>0.05).

Conclusions

The thermal treatment of Reciproc Blue produced a finer structure with smaller grains than Reciproc, which increased its fracture resistance and was also responsible for its reduced hardness and lower elastic modulus. Both files were safe during ex vivo usage in severely curved canals.

TMJ and Jaw Pain – Why Does My Jaw Hurt?

Wed, 04 Sep 2019 16:35:57 -0700

Trauma, dental problems, and other health conditions can cause jaw pain. Pain in the jaw can range from uncomfortable to extreme, but you don’t need to suffer in silence. Once a health professional diagnoses the source of your jaw pain, you can receive treatment to alleviate or eliminate your pain. Structure of Your Jaw The […]

The post TMJ and Jaw Pain – Why Does My Jaw Hurt? appeared first on 123Dentist.

From an assessment of multiple chelators, clodronate shows potential for use in continuous chelation

Wed, 04 Sep 2019 01:38:02 -0700

Abstract

Aim

To identify chelators which when mixed with sodium hypochlorite (NaOCl) are stable, exhibiting minimal loss of free available chlorine (FAC) over 80 minutes and to further investigate potential mixtures by assessing FAC over 18 hours and the capacity to remove smear layer.

Methodology

0.25 M EDTA (10%), 0.25 M EGTA (egtazic acid), 0.25 M CDTA (cyclohexanediaminetetraacetic acid), 0.25 M DTPA (pentetic acid), 0.5 M ATMP (aminotri(methylene phosphonic acid)) and 1 M HPAA, (hydroxyphosphonoacetic acid), all at alkaline pH, were mixed equally with 5% sodium hypochlorite (NaOCl). 0.5 M alkaline clodronate and 0.5 M Na₄etidronate (15%) were mixed equally with 10% NaOCl. For all mixtures, the pH and temperature were measured over 80 minutes and additionally for the clodronate mixture over 18 hours. Iodometric titration was used to measure the FAC of all mixtures except for HPAA. The following were compared with respect to their ability to remove smear layer: 1 M clodronate+10% NaOCl, 0.5 M clodronate+10% NaOCl, 1 M etidronate+10% NaOCl, 0.5 M clodronate+10% NaOCl and the sequences 5% NaOCl/17% EDTA/5% NaOCl and 5% NaOCl/17% EDTA. The area fraction occupied by open dentinal tubules as a percentage of the total area ( % AF) from scanning electron microscopy (SEM) micrographs was calculated using Image J. The results were statistically analysed with alpha set at 0.05.

Results

Compared to its control, the mixture 0.5 M clodronate+10% NaOCl lost no FAC over 18 hours (p > 0.05). The FAC of 0.25 M CDTA mixed with 5% NaOCl fell to 96%, 92%, 75% and 4.9% at 20, 40, 60 and 80 minutes respectively. Temperature rises were observed in all cases except in the etidronate and clodronate mixtures. Only in the clodronate mixture did the pH remain above pH 12 for the whole experiment. Although smear layer was removed, the % AF in 1 M clodronate+10% NaOCl, 0.5 M clodronate+10% NaOCl, 1 M etidronate+10% NaOCl was less than for 0.5 M etidronate+10% NaOCl and 5% NaOCl/17% EDTA/5% NaOCl and 5% NaOCl/17% EDTA.

Conclusion

Alkaline 0.5 M clodronate mixed equally with 10% NaOCl, has potential for use in continuous chelation, based on this assessment of stability and smear layer removal. Further research is needed to establish its efficacy and safety.

Treatment of immature teeth with nonvital pulps in adults: a prospective comparative clinical study comparing MTA with Ca(OH)2

Tue, 03 Sep 2019 09:49:53 -0700

Abstract

Aim

To evaluate and compare the influence of various predictors on outcomes of apexification using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) in permanent immature anterior teeth with necrotic pulps and periapical lesions of adults.

Methodology

Ninety immature teeth with necrotic pulps and periapical lesions on adult patients (aged 18–40 years) were treated with MTA (45 teeth) or CH (45 teeth) between 2015 and 2018. Patients of both groups were recalled for follow‐up examinations after the first intervention at 1,3,6 and 12 months for the first year, every 6 months for the second year and every year thereafter until the end of the study (median 32.3 months). The treatment outcome based on clinical and radiographic criteria was assessed by calibrated examiners and dichotomized as ‘healed+healing’ or ‘not healed’. The age, gender, stage of root development, preoperative signs and symptoms of apical periodontitis and size of periapical lesion were recorded. The cumulative success proportion and mean time were analysed with the Kaplan–Meier test. The generalized logrank statistic was used to describe prognostic clinical variables. Fisher's exact test was applied for the evaluation of the healing rates.

Results

Thirty‐nine of the 45 teeth treated with MTA were available for recall. Of these, 29 teeth (74%) revealed calcific apical barrier formation with complete resolution of periapical lesions, 7 teeth (18%) were healing, and 3 teeth (8%) had persistent disease. Thirty‐four of the 45 teeth in the CH group were available for recall. Of these, 27 teeth (79%) had complete healing of periapical lesions and had calcific barrier formation, 4 teeth (12%) were healing, and the remaining 3 teeth (9%) had not healed. The survival rate of teeth treated with MTA was similar to the survival rates observed in teeth treated with CH (90% and 91%, respectively, P > 0.05). The generalized logrank statistic revealed that the cumulative success rate of both materials was not significantly different (P > 0.05). None of the tested predictors had an influence on the treatment outcomes of teeth in both groups (P > 0.05).

Conclusions

Apexification treatment with both MTA and CH was associated with similar treatment outcomes. MTA may be proposed as a material for apexification treatment in immature teeth of adult patients due to the shorter treatment time associated with its use.

Potential immunomodulatory effects of stem cells from the apical papilla on Treg conversion in tissue regeneration for regenerative endodontic treatment

Mon, 02 Sep 2019 11:00:28 -0700

Abstract

Aim

To evaluate the expression of Foxp3‐positive lymphocytes around newly formed tissue after regenerative endodontic treatment (RET) in vivo and investigate the effects of stem cells from the apical papilla (SCAP) on the conversion of CD4⁺CD25⁻ T cells to CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) in vitro.

Methodology

Three 6‐month‐old beagles with nine doubled‐rooted premolars in each dog were randomly assigned to the RET group and the control group. RET was performed after apical periodontitis had been induced in the experimental immature teeth. Three months later, the expression of Foxp3 was detected in the histological sections by immunofluorescent staining. Human SCAP and CD4⁺CD25⁻ T cells from mice spleens (1 : 1 and 1 : 5) were co‐cultured in cell–cell contact or in Transwells, respectively, for 24 and 72 h in vitro. The percentage of Tregs was evaluated by flow cytometry. The results were analysed using the Fisher's exact test and analysis of variance. P < 0.05 was regarded as statistically significant.

Results

Inflammatory cells were present with tissue regeneration in the RET group, and Foxp3‐positive T cells were enriched around the newly formed tissues. SCAP promoted Treg conversion after 72 h in vitro. Cell–cell contact played an important role after the 24 h co‐culture, whilst soluble factors were also involved after 72 h (P < 0.05).

Conclusions

SCAP promoted the conversion of pro‐inflammatory T cells to Tregs in vitro. Tregs were enriched around the regenerating tissues in the root canals after RET, which may create a suitable immune microenvironment for the differentiation of SCAP. This study provides an underlying mechanism for tissue regeneration during RET.

Role of transient receptor potential vanilloid type 1 in the trigeminal ganglion and brain stem following dental pulp inflammation

Mon, 02 Sep 2019 10:54:10 -0700

Abstract

Aim

To verify whether experimentally induced pulpitis activates the expression of transient receptor potential vanilloid type 1 (TRPV1) and c‐Fos, both peripherally and centrally.

Methodology

Acute pulpitis was induced in Sprague‐Dawley rats via pulp exposure and application of complete Freund's adjuvant (CFA; n = 13). Saline‐treated (n = 13) rats and rats that did not undergo tooth preparation (n = 13) served as control groups. Three days post‐CFA or post‐saline application, face grooming activity was recorded, and the rats were then euthanized to allow for immunohistochemical analysis of the trigeminal ganglion (TG) and spinal trigeminal nucleus. anova with Student's t‐test for post‐hoc analysis was used to quantify the differences in behavioural tests and immunohistochemical labelling (c‐Fos and TRPV1) in TG amongst groups. Kruskal–Wallis test with Dunnett's test for post‐hoc analysis was used to compare immunohistochemical labelling (c‐Fos and TRPV1) in the brainstem amongst groups.

Results

Histological evidence of severe pulp inflammation was found, and there was a significant increase in pain‐like behaviour (P < 0.05) in CFA‐treated animals. C‐Fos labelling and TRPV1 immunoreactivity in the TG were significantly higher (both P < 0.05) in the CFA group than in the control groups. In the spinal trigeminal nucleus, the immunoreactivity for c‐Fos was absent in the intermediate region (trigeminal subnucleus interpolaris) in all animals, with comparable expression of TRPV1 amongst all groups. In contrast, neurons in the trigeminal subnucleus caudalis (TSC) exhibited significant c‐Fos immunoreactivity in the CFA group (P = 0.0063). The expression of TRPV1 did not differ amongst the three groups, but the superficial laminae of the TSC exhibited significantly greater expression of TRPV1 than did the deep layers (P = 0.0014).

Conclusions

Following acute pulp inflammation, the TRPV1 channel was significantly involved in nociceptive signal processing in the peripheral nervous system, but not in the CNS. Because pulpitis induced some neuronal activation at the brainstem levels, further studies are needed to identify additional transducers that mediate signal transmission from pulpal afferents to their central targets.

Influence of root maturity or periodontal involvement on dentinal collagen changes following NaOCl irrigation: an ex vivo study

Sat, 31 Aug 2019 02:09:37 -0700

Abstract

Aim

To refine a FTIR protocol for detection of NaOCl‐induced dentinal collagen changes using an ex vivo irrigation model, and to apply it to determine the collagen change within 0.5 mm of canal or root surfaces, with or without mature roots or periodontal involvement.

Methodology

The root canals of extracted human roots were irrigated with control saline (n = 3) or 5% NaOCl (n = 3) and sectioned into transverse disks for FTIR analyses, 0.5 mm from both the canal lumen and root surface, before and after surface treatment with 17% EDTA. Amide I/phosphate and amide II/phosphate absorbance ratios were compared using the Wilcoxon sign rank test. Mature roots without periodontal involvement were irrigated with: saline (n = 7), 5% NaOCl (n = 7) or 5% NaOCl + 17% EDTA (n = 7); those with periodontal involvement (n = 7) or immature roots (n = 7) were irrigated with 5% NaOCl. Dentine disks were then prepared for FTIR analyses. The effects of irrigant/root maturity/periodontal involvement were analysed using linear mixed models.

Results

FTIR analyses of the irrigated samples revealed a significant (P < 0.05) reduction in collagen bands near the canal lumen after NaOCl irrigation using surface EDTA‐treated samples. Irrigation with the test solutions resulted in significant (P < 0.0001) dentinal collagen changes in the mature roots, whilst those in the immature roots were significantly (P < 0.05) greater compared with the mature roots with or without periodontal involvement; but there was no difference between the latter groups.

Conclusion

EDTA surface treatment of polished dentine surfaces enhanced FTIR detection of NaOCl‐induced collagen changes. Both root maturity and irrigation protocol influenced the ability of NaOCl to alter dentinal collagen up to 0.5 mm from the canal lumen.

The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms

Sat, 31 Aug 2019 02:08:12 -0700

Abstract

Aim

To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism.

Methodology

Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3‐day and 21‐day‐old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture‐dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony‐forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05).

Results

Collagen conditioning significantly increased the number of CFUs in the 21‐day biofilms, compared to the 3‐day biofilms (P < 0.05). Although the biochemical analysis revealed that surface conditioning had no significant effect on the total carbohydrate content in the 21‐day biofilms, confocal microscopic analysis revealed that collagen and saliva conditioning selectively increased the polysaccharide content of 21‐day biofilms, compared to the 3‐day biofilms (P < 0.05).

Conclusions

The results of this study raise an important methodological concern that the substrate conditioning substances and biofilm age differentially influence the cellular and extracellular matrix components of E. faecalis biofilms.