Forced Orthodontic Extrusion to Restore the Unrestorable: A Proof of Concept.

The purpose of this clinical study was to assess the feasibility of forced orthodontic extrusion with the Tissue Master Concept to retain subgingivally fractured teeth as abutments for which extraction and replacement would be equal treatment opportunities. Participants were recruited from a group of consecutive patients in need of prosthodontic rehabilitation. In total, 36 deeply destroyed teeth in 31 patients underwent forced orthodontic extrusion with forces exceeding 50 g to reestablish biologic width and ensure a 2-mm dentin-ferrule design prior to single-crown restoration. The primary endpoint was the success of the extrusion in terms of the ability to restore the respective abutment tooth. Information about overall treatment time, frequency, and reasons for failure were collected. Four patients dropped out of the treatment. For the remaining 27 participants, data were fully collected. The amount of extrusion ranged between 2 and 6 mm (3.5 ± 0.9 mm), and the mean duration until retention was 20 ± 12 days. On average, patients returned three (± 3) times for control visits after extrusion. Adhesive failure (n = 6) and orthodontic relapse (n = 2) were the most frequent complication types. Forced orthodontic extrusion may be a useful tool to restore teeth evaluated as nonrestorable.

Systematic review fracture resistance of endodontically treated posterior teeth restored with fiber reinforced composites- a systematic review.

BACKGROUND: Large cavity designs and access cavities impair endodontically treated tooth fracture resistance. As the tooth's strength is known to reduce significantly after the root canal treatment, occlusal loading as a result of functions such as chewing, biting and certain parafunctional tendencies makes the endodontically treated tooth vulnerable to fracture. Hence, after endodontic treatment, it is vital to give adequate and appropriate restorative material to avoid tooth fractures. Accordingly, the choice of such restorative material should be dictated by the property of fracture resistance. OBJECTIVE: The goal of this study was to conduct a systematic review and critical analysis of available data from in vitro studies examining the fracture resistance of endodontically treated posterior teeth restored with fiber-reinforced composites. METHODOLOGY: The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRIS-MA) Statement was used to guide the reporting of this systematic review A comprehensive literature search was performed using MEDLINE (via PubMed), Scopus, ScienceDirect, Google Scholar, and LILACS. A manual search of the reference lists of the articles was also performed. The databases provided a total of 796 studies from the electronic systematic search. The databases provided a total of 796 studies from the electronic systematic search. Two reviewers scrutinized the papers for eligibility based on inclusion/exclusion criteria and extracted data. The studies were assessed for their potential risk of bias. Based on modified JBI & CRIS (checklist for reporting in vitro studies) guidelines, along with the methodology and treatment objective, we have formulated 13 parameters specifically to assess the risk of bias. A total of 18 studies met the inclusion criteria and were included for qualitative analysis. Considering the high heterogeneity of the studies included, a meta-analysis could not be performed. RESULTS: The majority of the included studies had a moderate or high risk of bias. When compared to traditional hybrid composites, fiber-reinforced composites showed increased fracture resistance of endodontically treated teeth in the majority of investigations. On the other hand, limited evidence was found for the bulk fill composites. Moreover, moderate evidence was found for the fracture resistance of inlays and fiber posts with fiber-reinforced composites for core build-up in endodontically treated teeth. No evidence could be found comparing the fracture resistance of endo crowns and fiber-reinforced composites in endodontically treated teeth. CONCLUSION: According to the research, using fiber-reinforced composites instead of conventional hybrid composites improves the fracture resistance of endodontically treated teeth. However, there was a high risk of bias in the research considered. No judgments could be reached about the superiority of one material over another based-on comparisons between other core restorations.

The effect of ultrasonic vibration protocols for cast post removal on the incidence of root dentin defects.

PURPOSE: To investigate the effects of two ultrasonic vibration protocols for cast post removal (single or double ultrasound units) on the development of defects in root dentin. METHODS: Sixty bovine incisors were selected. Fifteen roots were left unprepared (control). Forty-five roots were instrumented and filled. A 10-mm post space was prepared using #1-4 Largo drills. Fifteen teeth were prepared for post space and received no further procedure. Thirty roots had cast posts cemented and were submitted to ultrasonic vibration protocols for removal. The time necessary to remove each post was recorded. Roots were sectioned 3, 6, 9, and 12 mm from the coronal portion and viewed through a 25× magnification in a stereomicroscope. The presence of root fractures, partial cracks, and craze lines was registered. Chi-square and Fisher's exact tests were performed to compare the incidence of dentin defects. The Kruskal-Wallis test was performed to explore the difference between the time needed for post removal. The significance level was set at P = 0.05. RESULTS: Root defects were observed in all experimental groups. There were no statistical differences comparing previous root canal treatment and post removal steps, either with 1 or 2 ultrasonic units, in the formation of defects (P = 0.544) or fractures (P = 0.679). CONCLUSION: Ultrasonic vibration protocols for removing cast posts did not increase the number of dentin defects compared to root canal preparation and obturation and post space preparation steps.

Risk Factors for and Clinical Presentations Indicative of Vertical Root Fracture in Endodontically Treated Teeth: A Systematic Review and Meta-analysis.

INTRODUCTION: The aim of this study was to identify specific clinical signs or symptoms and potential risk factors which are most likely associated with the presence of a vertical root fracture (VRF) in endodontically treated teeth (ETT). METHODS: Electronic databases (MEDLINE via PubMed, EMBASE via Ovid, Scopus, and Web of Science) were searched by 2 reviewers in October 2022 for clinical studies, in which at least either the clinical presentation or potential risk factors associated with a VRF were assessed. Risk of bias was assessed using the Newcastle-Ottawa scale. Meta-analyses of odds ratios (ORs) were performed separately for several signs or symptoms and risk factors. RESULTS: Fourteen sources reporting on 2877 teeth (489 with VRF and 2388 without VRF) were included in the meta-analyses. Regarding the clinical presentation, the presence of sinus tracts (OR = 4.87; 95% confidence interval [CI], 1.58-15.0), increased periodontal probing depths (OR = 13.24; 95% CI, 5.44-32.22), swelling/abscess (OR = 2.86; 95% CI, 1.74-4.70), and tenderness to percussion (OR = 1.76; 95% CI, 1.18-2.61) were significantly associated with the presence of a VRF (Padj. value < .05). None of the assessed risk factors (sex, type of teeth, tooth location, posts, indirect restoration, and apical extension of the root canal filling) were found to be significantly associated with the presence of a VRF (Padj. value > .05). CONCLUSIONS: Four clinical presentations were identified to be the most significant signs or symptoms for a VRF in ETT: presence of sinus tracts, increased probing depths, swelling/abscess, and tenderness to percussion. None of the assessed risk factors pointed out to be significantly associated with a VRF. REGISTRATION: CRD42022354108 (PROSPERO).

Traumatic dental injuries in adults attending a London-based trauma clinic in the UK: a seven-year survey.

Introduction This survey reports the incidence of traumatic dental injuries in an adult population attending an adult dental trauma clinic in a London teaching hospital.Materials and methods Retrospective data were collected from patients attending an adult dental trauma clinic between 2012 and 2018.Results In total, 1,769 patients attended, with more men seen (1,030; 58.2%) compared to women (739; 41.8%) and this was statistically significant (p <0.05). The most common aetiological factor was an accidental fall (728; 41.15%), followed by assaults (413; 23.35%), bicycle accidents (253; 14.3%), sports injuries (132; 7.46%) and road traffic accidents (84; 4.75%). Lateral luxation (833) was the most common traumatic injury and this was followed by avulsions (362; 17%). Enamel-dentine fractures were the most common type of fracture injury (1,273; 64%).Discussion This retrospective survey attempts to report on the incidence of traumatic dental injuries in a London-based cohort of patients attending a specialised dental trauma clinic. In line with other reports, there were more men than women affected, which is probably attributed to behavioural activities.Conclusion(s) Accidental falls are the most common cause of a traumatic dental injury, lateral luxation was the most common type of displacement injury and enamel-dentine fractures were the most common type of fracture injury.

Traumatic dental injuries - practical management guide.

Traumatic dental injuries (TDIs) with a prevalence of 25% among school children and 33% among adults are a public health problem and can have a negative influence on the quality of life. The treatment prognosis of some teeth injuries is heavily dependent on the actions taken at the place of injury. The objective was to summarize evidence-based knowledge on the topic of TDIs and present a practical management guide for first aid in an accessible way. The authors searched the PubMed and Google Scholar databases. The review included only papers published in 2013 or later. Tooth injuries are proven to cause physical, social as well as economic consequences. The most frequent type of injury in primary dentition is avulsion, whereas crown fractures are most common in permanent dentition. TDIs occur most often at home and in school. Certain risk factors for TDIs were identified which include, among others, male gender, younger age, obesity. The general community knowledge of correct first aid in case of dental trauma is limited. Guidelines published by the International Association of Dental Traumatology include practical recommendations for first aid after avulsion. Permanent teeth should be replanted immediately at the accident site, whereas primary teeth should not be replanted when avulsed. Broken teeth fragments ought always to be collected if possible. After dental trauma it is vital that the patients seek professional help. Measures preventing TDIs (e.g., mouthguards) should be encouraged. It is of great importance that parents, teachers, guardians or bystanders witnessing a TDI are equipped to assist after a dental trauma or give advice on first aid when needed. Raising public awareness on the topic of dental injuries is a strongly advised general objective.

Effects of irradiation, restoration and crown fracture type on the maximum load to fracture traumatized incisors: An ex vivo study.

BACKGROUND/AIMS: Radiotherapy makes teeth prone to tooth fractures. However, the relationship between radiotherapy and maximum load to fracture teeth that suffered a crown fracture is not fully understood. The aim of this study was to evaluate the influence of fracture type, radiation dose, fracture time, and their interactions on maximum load to fracture irradiated teeth. MATERIAL AND METHODS: A total of 140 permanent incisors were divided into two fracture type groups (uncomplicated and complicated) each of which included seven radiation dose subgroups (0, 10, 20, 30, 40, 50, and 60). The test groups were exposed to high-energy X-ray at 2 Gy/day, 5 days/week for a total dose of 10-60 Gy. Control groups were not irradiated. The load where the specimen started to break was obtained two different times. The 1st fracture was performed after radiation therapy, and the 2nd fracture was performed after the restoration of these samples. RESULTS: Fracture type had no effect on the maximum load to fracture. In contrast, the maximum load to fracture teeth decreased with increasing radiation doses. Maximum load to fracture the restored teeth was lower than the 1st fracture results. The general linear model procedure revealed a significant interaction between radiation dose and fracture time. Similarly, there was a significant interaction between the fracture type, radiotherapy dose, and fracture time. Maximum load values of teeth with complicated crown fractures restored with fiber posts and composite were not affected by radiation. CONCLUSION: Teeth that have been subjected to radiotherapy have an increased risk of fracture during dental trauma. However, restoration of the irradiated teeth with fiber posts and composite resin did not affect the maximum load required to fracture them.

Success rate of fractured teeth receiving modified crown lengthening surgery and restorations.

BACKGROUND: Whether to preserve a structurally compromised tooth or remove it is a dilemma often encountered by clinicians. The aim of this study was to assess the long-term success rate of fractured teeth preserved by modified crown lengthening surgery and restorations. METHODS: Thirty-nine patients with a total of 45 fractured teeth who had received modified crown lengthening surgery were recruited and examined. Numbers of teeth lost were recorded, and the criteria for successful teeth were defined. Kaplan-Meier estimator was used to determine the success rate. Possible risk factors were compared between successful and unsuccessful groups by a Cox regression analysis to explore the potential predictors of failure with a significant level at α = 0.05. RESULTS: The mean ± SD of success time without considering variants was 6.2 ± 0.6 years (95% CI 5.1-7.7). The mean survival rates ± SD at 1.0-, 2.0-, 3.0-, 5.0-, 7.0-, and 9.0-year intervals was 97.8 ± 2.2%, 92.2 ± 4.4%, 72.8 ± 7.9%, 68.2 ± 8.6%, 60.7 ± 10.5%, and 40.4 ± 13.6%, respectively. Failure cases in teeth with poor plaque control and step-shaped fracture margin were significantly more than those with good plaque control and knife-shaped fracture margin (HR = 7.237, p = 0.011; HR = 15.399, p = 0.006; respectively). CONCLUSIONS: Fractured teeth treated with modified crown lengthening surgery are anticipated to have a high clinical success rate for 6.2 ± 0.6 years. Plaque control and fracture morphology appeared to be significantly associated with the success of the multidisciplinary treatment approach.

Present status and future directions: vertical root fractures in root filled teeth.

Vertical root fracture (VRF) is a common reason for the extraction of root filled teeth. The accurate diagnosis of VRF may be challenging due to the absence of clinical signs, whilst conventional radiographic assessment is often inconclusive. However, an understanding of the aetiology of VRFs, and more importantly, the key predisposing factors, is crucial in identifying teeth that may be susceptible. Thorough clinical examination with magnification and co-axial lighting is essential in identifying VRFs, and although CBCT is unable to reliably detect VRFs per se, the pattern of bone loss typically associated with VRF can be fully appreciated, and therefore, increases the probability of correct diagnosis and management. The prevalence of VRFs in root filled teeth is significantly greater than in teeth with vital pulps, demonstrating that the combination of loss of structural integrity, presence of pre-existing fractures and biochemical effects of loss of vitality is highly relevant. Careful assessment of the occlusal scheme, presence of deflective contacts and identification of parafunctional habits are imperative in both preventing and managing VRFs. Furthermore, anatomical factors such as root canal morphology may predispose certain teeth to VRF. The influence of access cavity design and root canal instrumentation protocols should be considered although the impact of these on the fracture resistance of root filled teeth is not clearly validated. The post-endodontic restoration of root filled teeth should be expedient and considerate to the residual tooth structure. Posts should be placed 'passively' and excessive 'post-space' preparation should be avoided. This narrative review aims to present the aetiology, potential predisposing factors, histopathology, diagnosis and management of VRF and present perspectives for future research. Currently, there are limited options other than extraction for the management of VRF, although root resection may be considered in multi-rooted teeth. Innovative techniques to 'repair' VRFs using both orthograde and surgical approaches require further research and validation. The prevention of VRFs is critical; identifying susceptible teeth, utilizing conservative endodontic procedures, together with expedient and appropriate post-endodontic restorative procedures is paramount to reducing the incidence of terminal VRFs.

Factors Related to Pulp Survival After Complicated Crown Fracture Following Vital Pulp Therapy: A Systematic Review and Meta-analysis.

INTRODUCTION: Crown fracture with pulp involvement and concomitant complications is a traumatic injury that may have several clinical considerations for dentists and patients. The aim of the present study was to appraise existing scientific evidence on factors related to pulp survival after complicated crown fracture following vital pulp therapy. METHODS: An electronic search was performed on 8 sources of published and unpublished literature, as of August 18, 2021. Randomized controlled trials and nonrandomized studies were included, involving patients undergoing treatment in teeth (mature or immature), with vital pulp, after complicated crown fracture. Risk of bias of included studies was examined and assessed through RoB 2.0 or the Risk of Bias in Nonrandomized Studies of Interventions tool, conditional on study design. Random effects meta-analyses were conducted, where applicable, and the certainty of evidence was evaluated through the Grading of Recommendations Assessment, Development, and Evaluation approach. RESULTS: Of the 506 initial articles, 24 were eligible for inclusion in the qualitative synthesis, and 7 ultimately contributed to meta-analyses. Based on synthesized evidence, in teeth treated with pulpotomy, there was no difference in successful clinical/radiographic outcome denoting pulp survival, when either bioceramic material versus CaOH2 (2 studies, Risk Ratio [RR] = 1.07; 95% confidence interval [CI], 0.99-1.16; P = .09; I2 = 0.0%), or mineral trioxide aggregate versus CaOH2 (2 studies, RR = 0.94; 95% CI, 0.76-1.16; P = .56; I2 = 0.0%). For different pulp management procedures, in pooled immature and mature teeth samples, there was no evidence that pulpotomy performed better than pulp capping with either CaOH2 or mineral trioxide aggregate (5 studies/6 comparisons, RR = 1.06; 95% CI, 0.71-1.58; P = .77; I2 = 74.8%). Risk of bias for randomized controlled trials ranged from raising some concerns to low, whereas nonrandomized studies were recorded as serious to critical risk of bias. CONCLUSIONS: The quality of the evidence was very low to moderate. The need for more carefully designed clinical trials in the field is profound, to inform high-quality clinical decision making.

Fracture Resistance of Titanium and Fiber Dental Posts: A Systematic Review and Meta-Analysis.

PURPOSE: The fracture resistance of dental post systems is influenced by the material of the post. The purpose of this systematic review and meta-analysis was to assess if there is a difference in fracture resistance between prefabricated dental titanium posts and fiber posts. METHODS: An online electronic search was performed using the PubMed, Scopus, and Web of Science databases for in vitro studies published from 2010 to 2020 in English. The retrieved eligible studies that compared the fracture resistance of titanium and fiber posts on human teeth were selected. The pooled standardized mean difference (SMD) with a 95% confidence interval was calculated. In addition, the trial sequential analysis (TSA) was performed to test if the available studies are sufficient to make conclusive evidence. RESULTS: Of the 1165 retrieved studies, 17 studies were included in the qualitative analysis, while 16 studies were included in the quantitative analysis. Because of the high heterogeneity among studies, data from 10 studies were pooled and submitted to TSA. A total of 852 teeth were evaluated for fracture of the posts in 27 independent comparison groups. The pooled effect of the residual studies revealed no significant difference between titanium and fiber posts (SMD = -0.12; 95% CI = -0.30, 0.06; p = 0.20). Results of the TSA revealed no conclusive evidence. CONCLUSIONS: The results of the current evidence revealed no significant difference between fiber and titanium posts. The evidence is insufficient, and more standardized in vitro studies are required.

Age-Related Pattern of Dental Trauma in a Nigerian Tertiary Health Institution

Abstract Objective: To evaluate the pattern of traumatic dental injuries among children, adolescents, and adults. Material and Methods: This was a cross-sectional analytic study of children and adults who presented with dental trauma. Data utilized for this study were sociodemographic characteristics, history of the traumatic incident, presenting complaints, traumatized teeth and classification of the traumatized tissues using Ellis and Davey's classification. Results: A total of 163 participants with 307 traumatized teeth were included in the study. The participants' age ranged from 2 years to 75 years, with a mean age of 25.36 ±15.4 years. Children <10 years were the least represented (14.7%), adolescents 10-19 years accounted for 23.9%., young adults 20 to 40 years were the most represented (44.8%) and older adults >40 years (16.6%). A higher proportion of the study participants were female 83 (50.9%) and the most prevalent complaint was broken teeth (57.1%) The most prevalent aetiology of the trauma documented was fall (36.2%). The most prevalent injury type was extended crown fracture with noticeable dentinal involvement without pulp exposure. There was a statistically significant association between injury type, aetiology and age group. Conclusion: Traumatic dental injuries affect children, adolescents and adults alike. The central incisors were the most vulnerable teeth across all age groups. Age was significantly associated with the etiology of dental trauma and injury type (AU).

Shrinkage Strains in the Dentin of Endodontically Treated Teeth with Water Loss.

INTRODUCTION: Dehydration has been considered as a potential contributor to vertical root fractures (VRFs) after root canal treatment (RCT). A loss of water could cause embrittlement of dentin and detrimental shrinkage strains. Senior patients have the highest risk of VRF. In this study, we characterized the spatial distribution in shrinkage of tooth roots with respect to donor age and prior RCT. METHODS: Single-rooted human teeth with and without prior RCT were collected from young (age <25 years) and old (age >60 years) adults. Transverse slices were sectioned from the apical, middle, and coronal thirds of the roots, and digital image correlation was used to evaluate shrinkage during free convection. Crack initiation and growth analysis was performed via optical microscopy, and bound water in dentin was characterized by Raman spectroscopy. RESULTS: The rate of shrinkage was significantly higher (p ≤ .05) in the apical third than in the middle and coronal thirds of all teeth regardless of donor age. The highest shrinkage strain occurred in the apical third of old donor teeth with prior RCT. In addition, the RCT-treated old teeth suffered the highest percentage of water loss with dehydration. Cracks initiated from the root surface and extended toward the canal with loss of water and shrinkage. CONCLUSIONS: The apical third undergoes significantly larger shrinkage strains with dehydration than the remainder of the root. Prior RCT exacerbates the extent of shrinkage, particularly in the teeth of seniors and after clinical function, which could increase the propensity for VRF.

Tooth and temporary filling material fractures caused by Cavit, Cavit W and Coltosol F: an in vitro study.

BACKGROUND: Tooth fractures can occur after temporary inter-appointment endodontic filling, resulting in not preserving and thus extraction of the affected tooth. The purpose of this investigation was therefore to evaluate the tooth substance fracture potential given by the expansion of endodontic temporary filling materials. METHODS: Tooth and access cavities were prepared in 80 mandibular molars. Four groups of 20 teeth each (Cavit, Cavit W and Coltosol F and control) were included. To simulate a clinical situation, the teeth were endodontically pre-treated and a calcium hydroxide dressing was placed. The cavities were filled with the corresponding temporary filling material, with exception of the control group, and kept submerged in distilled water for 15 days. The teeth were examined every 24 h by two calibrated observers under a stereomicroscope (7.5×), fractures of the temporary filling material and tooth structure were photo-documented, and the results statistically analyzed. Kaplan-Meier survival analysis were calculated to illustrate (survival = no fracture) probabilities to evaluate the time when the temporary filling material, tooth structure or both together occurred. Log-rank test was performed in order to assess significant differences between the materials and the subgroups used. RESULTS: Fractures were observed only in the Coltosol F group (p < 0.01), at the end of the observation period, a total of 13 teeth (65%) showed temporary filling material and eight teeth (40%) showed tooth structure fractures. No fractures in the pulp chamber area were observed at the end of the observation period in any group. CONCLUSIONS: Within the limitations of the current in vitro study, the results obtained suggest that tooth structure fractures caused by a temporary filling material can occur during endodontic treatment, thus compromising the success of the treatment.

Maxillofacial injury related to an exploding e-cigarette.

Electronic cigarettes (also known as e-cigarettes or electronic nicotine delivery systems) were invented in China in 2003 then introduced to the British market in 2007. They remain popular among the public and are deemed to be effective in reducing tobacco smoking (the UK being one of the first countries to embrace them in a harm reduction policy). However, reports in the media of e-cigarettes exploding are of concern, considering the potential functional and psychological impairment that lifelong disfigurement will cause, especially given their uptake among people of any age. We present a case of this rare, but dramatic, effect of e-cigarette use as a warning to the public.

Occurrence of Vertical Root Fractures after Apical Surgery: A Retrospective Analysis.

INTRODUCTION: Vertical root fractures (VRFs) are among the most frequent causes of tooth loss, mainly of endodontically treated teeth. However, very few data is available about the occurrence of VRFs following apical surgery. METHODS: Patient charts from 864 patients with 1058 teeth treated with apical surgery (September 1999 to December 2018) were retrospectively evaluated, if a VRF had occurred after surgery. The following, possibly influencing factors were analyzed: sex and age, type of treated tooth, primary versus resurgery, technique of root-end preparation, and timepoint of VRF diagnosis. Endpoints were either tooth extraction or the last follow-up. RESULTS: The study cohort (55% women, 45% men) had a mean age of 52.00 ± 13.97 years (range 9-93 years). The overall rate of VRFs after apical surgery was 4% (42 of 1058 teeth). Among these 42 teeth, 33.3% were mandibular first molars and 26.2% were maxillary second premolars. The most frequently affected root was the mesial root of mandibular first molars (28.6%). With regard to the study parameters, significant differences of VRF rates were observed only for the type of tooth treated. CONCLUSIONS: A low VRF rate of 4% was observed in this study. VRFs commonly occurred in maxillary premolars and mandibular molars, with the mesial root of mandibular first molars affected most frequently. This is in line with previous reports about VRFs in endodontically treated teeth without additional apical surgery.

Dentin thickness as a risk factor for vertical root fracture in endodontically treated teeth: a case-control study.

OBJECTIVES: This study evaluated factors associated with vertical root fracture in endodontically treated teeth, using a cone-beam computed tomography (CBCT) image database. MATERIALS AND METHODS: The sample for this case-control study consisted of 81 CBCT scans of teeth with vertical root fracture (VRF) and 81 CBCT scans of non-fractured teeth, matched by age, sex, and tooth position. The analyzed variables included dentin thickness, an intraradicular post, an adjacent implant, and a missing adjacent tooth. Student's t test test was used to compare the quantitative variables. The chi-square test was used to compare the categorical variables. Logistic regression was performed to evaluate the association between the presence of VRF and the independent factors assessed. RESULTS: The mean dentin thickness of fractured teeth was 1.3 mm, whereas that of non-fractured ones was 1.5 mm (p < 0.001). There was no difference between the fractured and non-fractured groups, regarding implant frequency or missing adjacent tooth (p > 0.05). There were a significantly larger number of teeth with posts in the fractured versus non-fractured group (p = 0.007). However, dentin thickness ≤ 1.3 mm was the only factor associated with VRF in the multiple regression model (OR = 3.60, 95%CI = 1.76-7.37). CONCLUSIONS: Dentin thickness may influence the development of VRF. Dentin thickness ≤ 1.3 mm is associated with a greater likelihood of fracture than ≥ 1.4 mm. CLINICAL RELEVANCE: This study suggests there may be a minimum amount of safe dentin thickness that should be preserved after endodontic instrumentation.

Baseline characteristics as 3-year predictors of tooth fracture and crack progression: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: The authors of this practice-based study estimated the risk of experiencing tooth fractures and crack progression over 3 years and correlated baseline patient-, tooth-, and crack-level characteristics with these outcomes. METHODS: Two-hundred-and-nine National Dental Practice-Based Research Network dentists enrolled a convenience sample of 2,601 participants with a cracked vital posterior tooth that had been examined for at least 1 recall visit over 3 years. Data were collected at the patient, tooth, and crack levels at baseline, annual follow-up visits, and any interim visits. Associations between these characteristics and the subsequent same-tooth fractures and crack progression were quantified. RESULTS: Of the 2,601 teeth with a crack or cracks at baseline, 78 (3.0%; 95% confidence interval, 2.4% to 3.7%) subsequently developed a fracture. Of the 1,889 patients untreated before year 1, 232 (12.3%; 95% confidence interval, 10.9% to 13.8%) had some type of crack progression. Baseline tooth-level characteristics associated with tooth fracture were the tooth was maxillary and had a wear facet through enamel and a crack was detectable with an explorer, on the facial surface, and in a horizontal direction. Crack progression was associated with males and teeth with multiple cracks at baseline; teeth with a baseline facial crack were less likely to show crack progression. There was no commonality between characteristics associated with tooth fracture and those associated with crack progression. CONCLUSIONS: Development of tooth fractures and crack progression over 3 years were rare occurrences. Specific characteristics were associated with the development of tooth fracture and crack progression, although none were common to both. PRACTICAL IMPLICATIONS: This information can aid dentists in assessing factors that place posterior cracked teeth at risk of experiencing adverse outcomes.

Resistance to fracture of intraradicular posts made of biological materials.

BACKGROUND: The aim was to analyze the fracture resistance of human teeth treated endodontically and restored with posts made of bovine dentin, human dentin, or glass fiber, and to evaluate the fracture pattern. METHODS: Cylindrical posts of 1.5 mm in diameter cemented to the roots of human maxillary canines presented a length of 15 mm, cervical diameter of 5-5.5 mm in the mesiodistal direction, and 7-7.5 mm in the vestibule-palatal direction. The groups studied were: Group I-10 glass fiber posts; Group II-10 human dentin posts; Group III-10 bovine dentin posts (self-adhesive resin cement); and Group IV-10 bovine dentin posts (resin-modified glass-ionomer cements). The coronal part of tooth was restored with a standardized core build-up using composite. All of the groups were submitted to a compression force test and the resistance to fracture was verified using a universal testing machine. The fracture pattern was likewise evaluated. RESULTS: The values of resistance to fracture were: 723.3N in group I, 561.5N in group II, 556.6N in group III, and, 613.27N in group IV. However, no statistically significant difference was observed among the groups. The fractures in groups I and II were most commonly found in the middle/apical third and were considered irreparable. For restored teeth in group III, half of the fractures appeared in the cervical third and were reparable. In group IV, all of the fractures were reparable, with the majority in the cervical thirds. CONCLUSION: Bovine dentin can be used as intraradicular post to substitute human dentin and glass fiber posts. The greater the malleability of the post, the greater the chances of survival of the teeth when subjected to fracture testing.