Factors Influencing Vertical Radicular Fractures in Teeth Supported by Metallic Dental Core: A Scoping Review

Purpose

The aim of this work is to conduct a literature review to highlight all the parameters involved in sub-prosthetic radicular fractures of teeth supported by metallic dental core.

Materials and Methods

The following research was performed among published studies over the last 10 years in two PubMed/Medline and Scopus and supplemented by manual searching within the bibliographies. The search was restricted to publications in English and French.

Results

Out of the 1464 articles initially identified, 18 studies met our inclusion criteria and were subsequently included in the literature review. These consisted of eight Finite Element Analysis Studies, two Retrospective Studies and one Randomized Controlled Trial. The results of this review show that radicular fractures are influenced by several variables, including predisposition, with maxillary premolars and mandibular molars being the most commonly affected teeth. Intracanal preparation can induce crack formation, leading to localized high stress concentrations. Increased ferrule height to 2 mm significantly enhances dental fracture resistance. Using high modulus of elasticity alloys results in nearly complete stress transmission to dentin due to their limited deformability and absorption capacity. The highest fracture resistance is achieved when posts are sealed using resin-modified glass-ionomer cement. Longer posts may be preferable to prevent vertical fractures. Additionally, occlusal factors, through repetitive stresses, contribute to crack propagation from surface defects, a phenomenon termed fatigue fracture.

Conclusion

These findings have significant implications. Practitioners should be aware of the predisposition of certain teeth, the importance of preserving the ferrule effect, the choice of root post materials, post Cement Material and the role of occlusal forces in managing and preventing vertical root fractures.

Mechanisms of dental injuries in basketball, United States, 2003-2022

BACKGROUND/AIM

Oral injuries such as oral soft tissue lacerations and contusions can occur in basketball by mechanisms such as running into other players or falling. Given a high enough impact force, dental injuries such as tooth fractures and avulsions can occur. Previous research has studied the different types of oral injuries as well as the mechanisms that cause them. Yet, the mechanisms resulting in dental injuries have remained unexplored. The aims of this study were to investigate the distribution of different oral injuries within each injury mechanism and evaluate which mechanisms were most likely to lead to a dental injury.

MATERIALS AND METHODS

This is a retrospective cohort study using the National Electronic Injury Surveillance System (NEISS). Subjects who experienced oral injuries from basketball between January 1, 2003 and December 31, 2022 were included in this study. The independent variable was the injury mechanism. The dependent variable was the dental injury outcome (yes/no). Multivariate logistic regression was used to measure the association between the injury mechanism and the dental injury outcome. A p < .05 was considered statistically significant.

RESULTS

This study included 4419 subjects who experienced oral injuries (national estimate, 138,980). Approximately 14.7% of oral injuries were dental injuries. Subjects experiencing collisions with objects such as walls or the basketball hoop (odds ratio (OR), 4.39; p < .001), falls (OR, 3.35; p < .001), or contact with the basketball (OR, 1.77; p = .006) had significantly higher odds of sustaining a dental injury relative to those experiencing contact with another player.

CONCLUSIONS

Basketball players experiencing contact to the mouth have high odds of sustaining a dental injury. An understanding of injury mechanisms is important for medical teams to manage these injuries and for coaches to educate athletes on safe and proper playing styles. Furthermore, healthcare providers and basketball staff should encourage athletes to wear mouthguards to reduce the risk of traumatic dental injuries.

Retrospective Assessment of Endodontically Treated Teeth Replaced by Dental Implants

INTRODUCTION

This study investigated endodontically treated teeth that were replaced by dental implants at the University of North Carolina (UNC) at Chapel Hill School of Dentistry. The primary objective of this study was to determine the reasons leading to the extraction of endodontically treated teeth and their subsequent replacement with dental implants. The secondary objective was to evaluate the proportion of these teeth that, according to experienced endodontists, could have been preserved.

METHODS

The UNC-Chapel Hill's dental electronic health records between 2004 and 2019 were probed for implant placement that replaced root canal-treated teeth. Preextraction radiographs and clinical charts were examined to ascertain the primary reason related to the extraction and to compile a profile for each case. In cases in which endodontic failure was the primary reason for extraction, radiographs and clinical findings were evaluated by 2experienced endodontists to assess potential treatment options.

RESULTS

Between 2004 and 2019, 29.3% (1564 of 5229) of teeth replaced by dental implants at UNC School of Dentistry had undergone root canal treatment, with the mandibular first molar being the most commonly replaced tooth. The leading reasons for extraction were recurrent caries associated with defective restoration (26.6%), fracture of coronal structure (21.5%), vertical root fracture (20.9%), compromised periodontal condition (13.8%), and endodontic failure (2.4%). Two experienced endodontists evaluated extractions due to endodontic failure and concluded that 61.7% of them could have been candidates for endodontic retreatment.

CONCLUSION

Substantial loss of tooth structure was the leading cause of extraction of root canal-treated teeth, followed by vertical root fracture and periodontal disease. Although endodontic failure constituted a minor portion of the reasons for extraction, a considerable number of teeth were extracted due to vertical root fractures following root canal treatment. A significant proportion of the extracted teeth due to endodontic failure could have been considered as potential candidates for endodontic retreatment.

Fracture Strength of Tooth Roots Following Canal Preparation by Three Rotary File Systems: An In Vitro Study

BACKGROUND

Since the beginning of modern endodontics, there have been many concepts, strategies, and techniques for root canal preparation. A mind-boggling variety of files have developed for negotiating and shaping them throughout the years. Today's most secure, most effective, and simplest file system combines the most reliable design elements of the past with the latest technological advances to create the most effective file system. So, the need for the study is to evaluate the fracture strength of tooth roots following canal preparation by three rotary file systems: ProTaper Universal file system (Dentsply, USA), ProTaper Next file system (Dentsply Sirona USA), and Neolix A1 nickel-titanium (NiTi) file system (Orikam Healthcare India Pvt Ltd., New Delhi, India).

METHOD

Ninety human mandibular molars were selected for the study. Inclusion criteria include human mandibular first and second molars and teeth removed for routine clinical reasons, and intact apices were selected, excluding cases with root surface caries, root surface fissures, teeth with immature root apex, mesial canal fusion, extremely short roots, thin roots, or curved roots. All teeth were preserved in a solution of 10% neutral buffered formalin for two weeks and then transferred to distilled water for examination. The teeth were randomly divided into three groups. Access cavities were created, and working lengths were determined. Groups 1, 2, and 3 underwent shaping using ProTaper Universal, ProTaper Next, and Neolix A1 (NiTi) file systems, respectively, following guidelines. Canals were irrigated with sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA) and were obturated up to the mid-root region with AH Plus sealer. To facilitate fracture testing, obturation was performed to distribute the load from the spreader to the canal wall. The EndoSequence and Quick-Fill obturation system were utilized to fill the apical half of the canal with gutta-percha material. After obturation, the distal root of each tooth was cut, while the mesial root was securely positioned in a putty material. A universal testing machine was employed for the fracture tests, operating at a cross-head speed of 1 mm/min. The machine was equipped with a D11 hand spreader tip, which was inserted into the root canal to make contact with the gutta-percha. Gradual force was applied to the root canal until a fracture occurred, at which point the force application was stopped. The amount of force required to cause the fracture was measured in newtons. Data were collected and recorded using IBM SPSS Statistics for Windows, Version 17.0 (Released 2008; IBM Corp., Armonk, New York, United States) and then transferred to Microsoft Excel for analysis. Descriptive statistics, mean, and standard deviation were used for continuous data. The fracture resistance of dental roots treated with three types of files was compared using a one-way ANOVA. Graphs were generated using Excel and Word. A significance level of p<0.01 was chosen.

RESULT

ANOVA indicated significant differences in mean fracture resistance: Neolix A1 (NiTi) (95.3 N) > NEXT (91.0 N) > universal (86.6 N), with a p-value of 0.004 (<0.001), confirming statistical significance.

CONCLUSION

The study concludes that the canal instrumented with Neolix A1 (NiTi) exhibits higher fracture resistance after canal instrumentation compared to ProTaper Next and ProTaper Universal.

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 10: First aid education

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 4: Faceshields for the prevention of dental and oral trauma

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 6: Education

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 2: Primary prevention of dental trauma across the life course

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 3: Mouthguards for the prevention of dental and oral trauma

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 8: ToothSOS app

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 5: Secondary prevention of dental injuries

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

The International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD) guidelines for prevention of traumatic dental injuries: Part 1: General introduction

The Guidelines for Prevention of Traumatic Dental Injuries were reviewed and approved by the Board of Directors of the International Association of Dental Traumatology (IADT) and the Academy for Sports Dentistry (ASD).

Investigation of Anterior Teeth Fractures Among Students Aged Between 8 and 13 Years in Hyderabad, India

Introduction Trauma involving anterior teeth stands as a prevalent type of dental injury among school-age children, impacting physical, psychological, and social well-being. This study aimed to assess the occurrence of fractures in anterior teeth among school children in Hyderabad and its associated risk factors. Materials and methods This research incorporated a cross-sectional analysis, involving 2046 children in the age group of 8 to 13 years from different schools in Hyderabad City. Alongside clinical evaluations, all participants completed a questionnaire regarding traumatic dental injuries.  Results Results indicated a prevalence rate of 8.5%, notably higher among younger boys. Factors such as lip competence coverage, increased overjet, and malocclusion with maxillary incisor proclination were associated with a heightened risk of such injuries. The peak incidence was observed at age 12, with fractures involving enamel and dentin being the most common type, predominantly affecting the maxillary central incisors. Conclusion The findings emphasize the significance of educational programs aimed at enhancing awareness and understanding of dental injuries among parents, students, and school staff.

Computer-Aided Design/Computer-Aided Manufacturing of Customized Abutment for Rehabilitating a Malpositioned Implant Using Digital Flow: A Case Report

This study presented a rehabilitation option for malpositioned implants; this involved obtaining their position and inclination through intraoral scanning, and producing a customized abutment with CAD/CAM technology. The patient in this case report presented a root fracture in tooth 21 and was subjected to extraction, implant installation, and immediate provisional prosthesis. The implant was installed with a distal inclination due to anatomical limitations. After osseointegration, an intraoral scanning transfer provided a digital model (file extension .stl), which reproduced the implant's position and inclination. Then, the file was sent so that a customized abutment (CAD/CAM) could be manufactured, promoting the final rehabilitation of the case; this allowed for good hygiene, load distribution in the dynamic interocclusal relationship, and favorable esthetics, whereas many would otherwise recommend implant removal. The result presented lower costs, a shorter time frame, and a lower morbidity for the patient.

Immediate autotransplantation of a mandibular premolar with complete roots to a fractured tooth site, using platelet-rich fibrin in an orthodontic patient, report of a case

Transplantation of one tooth to another site in the same individual can be considered an attractive alternative to dental implants or fixed prostheses. This study reports the treatment results of a 16-year-old female with severe crowding in upper and lower arches and a fractured mandibular premolar with a poor prognosis. The crowding of the lower left quadrant was relieved by the extraction of the first premolar. This extracted tooth with a complete root was transplanted to the right quadrant with the fractured tooth. Platelet-rich fibrin can stimulate and accelerate periodontal healing. The platelet concentrate of this patient was prepared and applied to the socket wall at the time of surgery. The acceptable occlusion and the excellent 4-year prognosis of the transplanted tooth are presented.

Prevalence and Patterns of Traumatic Dental Injuries in the Permanent Dentition: A Three-Year Retrospective Overview Study at the University Dental Clinic of Vienna

The aim of this study was to retrospectively analyze the prevalence and patterns of traumatic dental injuries (TDIs) in permanent teeth at the University Dental Clinic of Vienna and examine influential variables. The study included all patients with dental trauma in permanent teeth who presented at the University Dental Clinic of Vienna (Austria) between 2014 and 2016. Dental records, including age, gender, location of trauma, type of trauma, cause of TDI, and location of the traumatic incident, were obtained. Clinical oral and radiographic examinations were conducted in accordance with the current guidelines of the German Society of Dental, Oral, and Craniomandibular Sciences (DGZMK). The sample comprised 1132 permanent teeth of 578 patients with TDIs. The most frequently injured teeth were upper central incisors (n = 719, 63.5%), followed by upper lateral incisors (n = 231, 20.4%). Fractures were the most frequent injury type (53%, n = 596). TDIs mostly occur due to falling accidents. The majority of traumatic incidents occurred at home (79.4%, n = 459). The injury characteristics are comparable to the results of other international studies. Due to the high prevalence of TDIs in dental medicine, dental practitioners should be equipped to effectively manage their immediate care and treat potential long-term complications.

Complicated Crown Fracture of Permanent Incisors: A Conservative Treatment Case Report and a Narrative Review

Dental trauma may have a severe impact on the social and psychological wellbeing of a patient. Most cases of dental injuries involve anterior teeth, especially the maxillary upper incisors. Crown fractures, with or without pulp exposure, are the most common trauma in permanent dentition. There are many methods of management, in which the initial state of the pulp, the time since the injury, and the presence of an accompanying injury play a key role. This case report aimed at showing a possible conservative treatment after complicated tooth fracture that consisted of partial pulpotomy followed by adhesive reattachment of the tooth fragment using a technique based on heated resin composite. Such a specific procedure represents a conservative approach to traumatic coronal lesions, providing a suitable opportunity to maintain the tooth vitality, aesthetics, and function. Indeed, reattachment of tooth fragment using a composite/adhesive is a simple technique to achieve excellent results in terms of aesthetic and function.

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.

Prosthetic restoration after atraumatic surgical extrusion: a report of two cases

Preservation and restoration of teeth with little coronal tooth structure due to crown-root fractures or caries lesions, ensuring restoration margins do not encroach on the biologic width, constitute a challenge. Available treatment options include surgical crown lengthening and orthodontic or surgical extrusion. This report presents two patients in which teeth were restored by surgical extrusion with an atraumatic extraction system and prosthetic therapy.

Study on fracture behavior of molars based on three-dimensional high-precision computerized tomography scanning and numerical simulation

A series of three-dimensional (3D) numerical simulations are conducted to investigate the gradual failure process of molars in this study. The real morphology and internal mesoscopic structure of a whole tooth are implemented into the numerical simulations through computerized tomography scanning, digital image processing, and 3D matrix mapping. The failure process of the whole tooth subject to compressions including crack initiation, crack propagation, and final failure pattern is reproduced using 3D realistic failure process analysis (RFPA3D) method. It is concluded that a series of microcracks are gradually initiated, nucleated, and subsequently interconnect to form macroscopic cracks when the teeth are under over-compressions. The propagation of the macroscopic cracks results in the formation of fracture surfaces and penetrating cracks, which are essential signs and manifestations of the tooth failure. Moreover, the simulations reveal that, the material heterogeneity is a critical factor that affects the mechanical properties and fracture modes of the teeth, which vary from crown fractures to crown-root fractures and root fractures depending on different homogeneity indices.

Present status and future directions: Endodontic management of traumatic injuries to permanent teeth

The prognosis of traumatized teeth depends largely on the fate of the pulp and its treatment. This review aims to update the present status on the endodontic management of traumatic injuries to permanent teeth and to identify relevant research areas that could contribute to an improvement in diagnosis and treatment of traumatized permanent teeth. Future research should pay greater attention to (1) diagnostic methods to assess the perfusion of the pulp and enhance detection of tooth cracks and initial signs of root resorption; (2) improved materials for vital pulp treatment; (3) studies focusing on type and duration of splinting after root fractures; (4) antiresorptive intracanal medication in case of posttraumatic pulp necrosis and infection-related resorption and (5) long-term data on the apical barrier technique compared to revitalization.

Management of extrusive luxation of upper incisors in young permanent teeth: a case report

This case report documents the clinical approach adopted for two permanent maxillary incisors with extrusive luxation in a 16-year-old boy. The proposed procedures involved reposition of both teeth, by digital pressure and stabilized by using semi-rigid splint for 2 weeks. Endodontic therapy was performed. Clinical and radiographic follow-up examinations were conducted at 6-month intervals for two years. Assessment revealed the absence of pulpal and periapical disease and the restoration of the maxillary incisors to a state of health and normal function. A long-term clinical and radiological follow-up is needed to prevent and precociously detect possible complications that may occur following a extrusive luxation.

A critical analysis of research methods and experimental models to study dentinal microcracks

The purpose of this narrative review was to discuss the scientific milestones that led to the current understanding of the root dentinal microcrack phenomenon based on the interplay between the usage of micro-computed tomography (micro-CT) as an analytical tool alongside a close-to-mouth experimental model. In 2009, reports on the development of dentinal microcracks in extracted teeth after root canal preparation triggered an awareness of the potential for vertical root fractures (VRFs) of endodontically treated teeth could be developed from defects created by the mechanical stress of nickel-titanium preparation systems on dentine. This assumption was taken for granted, even though no cause-effect relationship had been scientifically demonstrated. Since then, several studies using the sectioning method with extracted teeth have been published and the large discrepancy amongst their outcomes soon become evident. Moreover, the high frequency of reported dentinal microcracks largely contrasted with the clinical incidence of VRFs, raising doubts on their methodological reliability. Using micro-CT technology, it was demonstrated by several studies that, in extracted teeth, dentinal defects already existed before the endodontic procedures, indicating that the initial reports framed a non-existing cause-effect relationship between canal preparation and dentinal microcracks. Although these new findings contributed to a better comprehension of this phenomenon, the misconception that microcracks were the starting point for VRFs was only surpassed with a new in situ approach using fresh cadavers. Surprisingly, microcracks were not identified in sound teeth. As a conclusion, dentinal microcracks in extracted teeth can be considered a non-natural occurrence observed only in a laboratory set-up as a consequence of dehydration and storage conditions. Thus, dentinal microcracks shall not be considered as the starting point for VRFs as they do not manifest in non-extracted teeth. Identifying dentinal microcracks as a laboratory phenomenon highlights the impact of recent scientific developments to disclaim the clinical relevance of laboratory-obtained outcomes.

Decision-Making and Management of Immature Permanent Teeth with Crown Fractures in Small Animals-A Review

Immature permanent teeth with crown fractures present a unique challenge in human and animal patients. Immature permanent teeth have not yet developed completely, often presenting with thin dentin walls, incomplete apical formation, and increased crown-to-root ratios. Loss of pulp function at this stage has devastating long-term implications for these teeth. Ideally, attempts should be made to preserve pulp vitality in immature permanent teeth to allow for continued dental development. The range of treatment options for vital teeth includes odontoplasty with bonding and sealing +/- restoration, indirect pulp capping, and direct pulp capping/vital pulp therapy. These treatments have long been established in human and veterinary medicine, and cases have been reported in dogs and cats. Apexification using calcium hydroxide is a well-established treatment for nonvital immature teeth. The advent of mineral trioxide aggregate and other bioceramic materials for use in vital pulp therapy and apexification has reduced treatment sessions and improved outcomes. Recent developments in the field of regenerative endodontic therapy further expand treatment options and provide the possibility for continued development of a formerly nonvital tooth. Selecting the appropriate treatment based on the severity of tooth fracture and status of pulp vitality can avoid a lifetime of poor structure and function for the affected tooth. This article provides multiple step-by-step protocols for the management of immature permanent teeth with crown fractures in small animals.

Influence of size of field of view (FOV), position within the FOV, and scanning mode on the detection of root fracture and observer's perception of artifacts in CBCT images

OBJECTIVE

To assess the influence of field of view (FOV) size, scanning position within the FOV and scanning mode on the detection of root fracture and artifact perception.

METHODS

Forty single-rooted premolars restored with NiCr and AgPd posts were divided into two groups: fractured and sound. All teeth were scanned using four CBCT scanning protocols varying FOV sizes (80 × 80 mm and 50 × 55 mm) and scanning modes (Standard and High Definition). The sample was positioned within the FOV in two pre-set positions (central and lateral) and in four positions established by the operator (quadrants). Detection of root fracture and artifact perception were assessed by two observers using 5-point and 4-point scales. Sensitivity, specificity, accuracy, and AUC values were calculated and compared by ANOVA two-way and Tukey's test. Chi-square and Fisher's exact test were used to assess artifact perception. The level of significance was set at p < 0.05.

RESULTS

The central position within the FOV presented higher sensitivity, specificity, accuracy, and AUC values and differed from the lateral position within the FOV for the studied metal posts (p<0.05). Quadrant 2 presented the best sensitivity, accuracy, and AUC values (p<0.05). The lateral position within the FOV, AgPd posts, quadrants 1 and 3 and protocols 1 (SM, 80 × 80) and 2 (HD, 80× 80) presented higher frequency of artifacts classified as "severe".

CONCLUSION

Positioning the object in the center or closer to the anterior periphery of the FOV while using a small FOV improved the detection of root fracture and decreased artifact perception.

Conservative Treatment of Complicated Crown Fracture and Crown-Root Fracture of Young Permanent Incisor-A Case Report with 24-Month Follow-Up

The complicated crown-root fracture of young permanent teeth is an uncommon traumatic dental injury that is usually treated in a complex way and is demanding not only for the dentist but even for the treated child. In this case report, we present the conservative treatment of a maxillary central incisor in a 10-year-old boy after a traumatic dental injury. Treatment included partial pulpotomy and adhesive fragment reattachment after reflection of the mucoperiosteal flap. The patient was fully asymptomatic at 24-month follow-up, with an aesthetically acceptable outcome. Vital pulp therapy and adhesive fragment reattachment can be a viable treatment option for complicated crown-root fractures, especially when treating immature permanent teeth.

Fracture resistance of endodontically treated premolars restored with bulk-fill composite resins: The effect of fiber reinforcement

BACKGROUND

Coronal restoration of endodontically treated teeth (ETT) with mesio-occluso-distal (MOD) cavities is of a great importance in long-term success of the treatment. This study evaluated the effect of fiber reinforcement on the fracture resistance (FR) of ETT restored with flowable or paste bulk (PB)-fill composite resin compared to conventional composite (CC) resin.

MATERIALS AND METHODS

In this in vitro experimental study, eighty maxillary premolars were divided into eight groups (n = 10). The first group was left intact (G₁) and the other groups received MOD cavities along with endodontic treatment. G₂: Remained unrestored while the other experimental groups were restored with three types of composite resin with or without fiber insertion. G₃: CC resin, G₄: PB fill, G₅: Flowable bulk fill (FB). G₆: Fiber + CC, G₇: Fiber + PB, and G₈: Fiber + FB. FR was tested at crosshead speed of 1 mm/min and recorded in Newton. Data were analyzed using one-way analysis of variance and Tukey's tests at significance level of P < 0.05.

RESULTS

G₁ and G2 revealed the highest and the lowest FR, respectively. The mean FR of the testing groups in Newton was as follows: G₁ = 1204.8 ^A, G₂ = 352.1 ^C, G₃ = 579.6 ^BD, G₄ = 596.7 ^BD, G₅ = 624.9 ^BDE, G₆ = 858.3 ^E, G₇ = 529.6 ^CB, and G₈ = 802.5^DE. Different uppercase letters indicate the significant difference between the groups.

CONCLUSION

The effect of fiber insertion on FR depended on the type of composite resin; the highest reinforcing effect was obtained in the CC resin + fiber, followed by bulk-fill flowable + fiber, and flowable bulk (FB)-fill composite resin. The strength of the former was significantly higher than the conventional and PB fill with and without fiber.

European Society of Endodontology position statement: endodontic management of traumatized permanent teeth

This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the endodontic management of traumatized permanent teeth. A recent comprehensive review with detailed background information provides the basis for this position statement (Krastl et al. 2021, International Endodontic Journal, https://doi.org/10.1111/iej.13508). The statement is based on current scientific evidence as well as the expertise of the committee. Complementing the recently revised guidelines of the International Association of Dental Traumatology, this position statement aims to provide clinical guidance for the choice of the appropriate endodontic approach for traumatized permanent teeth. Given the dynamic nature of research in this area, this position statement will be updated at appropriate intervals.

Endodontic management of traumatized permanent teeth: a comprehensive review

The pulp plays a key role in the treatment of traumatic dental injuries (TDIs) and is strongly associated with the outcome, particularly in severe cases. A correct pulp diagnosis is essential as it forms the basis for developing the appropriate management strategy. However, many TDIs are complex, and their treatment requires a profound knowledge of the physiological and pathological responses of the affected tissues. This comprehensive review will look at the dentine-pulp complex and its interaction with the surrounding tissues following TDIs. The literature up to 2020 was reviewed based on several searches on PubMed and the Cochrane Library using relevant terms. In addition to the recently revised guidelines of the International Association of Dental Traumatology, this article aims to provide background information with a focus on endodontic aspects and to gather evidence on which a clinician can make decisions on the choice of the appropriate endodontic approach for traumatized permanent teeth.

Accuracy of three cone-beam CT devices and two software systems in the detection of vertical root fractures

OBJECTIVES

The aim of this study was to compare the accuracy of vertical root fracture (VRF) detection using three tomography devices and two software systems in teeth with different endodontic fillings.

METHODS

The sample consisted of 45 premolars divided into 3 groups: No filling (NF, n=15); Gutta percha (GP, n=15) and Metallic Post (MP, n=15). Cone-beam computed tomography (CBCT) images were acquired in Kodak 9000 3D, Orthopantomography 300 (OP300) and PreXion 3D devices, before and after induced root fractures. Two oral radiologists analyzed all images using InVivoDental and e-Vol DX software systems. The analysis was repeated after 15 days in 30% of the sample. Data analysis compared receiver operating characteristic (ROC) curves, as well the areas under the ROC curves. Accuracy, sensitivity, specificity, positive and negative predictive value were calculated according to each tomographic device and software. Intra- and interexaminer reliability were tested using the Kappa coefficient.

RESULTS

The highest accuracy was seen in the image set from the PreXion 3D, using InVivo (0.96) or e-Vol DX (0.92) in image analysis. The OP300 device presented a similar performance of the PreXion 3D in teeth with different endodontic fillings. When using e-Vol DX, the accuracy of Kodak 9000 3D improved from 0.62 to 0.74.

CONCLUSIONS

The PreXion 3D device is the most accurate when detecting VRF, with a performance similar to the OP300 in endodontic filled teeth. Kodak 9000 3D is indicated for teeth without fillings, with better accuracy using e-Vol DX software.

On the ability of experimental impact measures to predict tooth injuries in an ex vivo swine model

BACKGROUND/AIM

Impact to the orofacial region, in particular teeth, is a frequent incident leading to injury in many sports and can result in health and economic costs for the injured individual. The majority of previous work has applied synthetic models such as plaster or stone, to form analogs of relevant structures to study the potential for impact-induced injury. Biomechanical studies that have applied tissue models (animal or human) for the purpose of determining the biomechanical measures associated with dental injury are rare. The aim of this study was to apply a simple ex vivo model based on swine dentition to ascertain which of a select list of measurable quantities associated with impact mechanics could predict luxation and fracture of teeth due to impact.

METHODS

Mandibular central incisors of ex vivo swine dentitions were impacted using a linear drop tower with heights ranging from 1.20 m to 2.42 m. Seven mechanical predictors were assessed at impact and were then subjected to binary logistic regression techniques to determine which was the best predictor of luxations or fractures of the teeth.

RESULTS

Of the seven mechanical predictors, (1) the velocity of the impacting body (R²  = 0.477), (2) a proxy measure for the change in kinetic energy of the impacting body (R²  = 0.586), and (3) the approximate energy absorbed by the tissue (R²  = 0.722) were found to be statistically significantly different (p < .05), offering the greatest specificity as indicated by receiver operator characteristics. Other measures that are frequently used in impact mechanics, including peak linear acceleration and velocity change, were not statistically significant predictors of tooth injury.

CONCLUSION

Identifying mechanical predictors for dental injury of unprotected teeth provides a first step in understanding which aspects of an impact event attribute to dental injury and can lay the foundation for future studies that examine alteration in injury mechanics associated with protection devices.

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.

Effect of Alternative Palatal Root Access Technique on Fracture Resistance of Root Canal Treated Maxillary Fourth Premolar Teeth in Dogs

A biomechanical study was performed to identify the effect of different treatment methods for difficult to instrument palatal roots on the fracture resistance of root canal treated maxillary fourth premolar teeth in dogs. Forty maxillary fourth premolar teeth with surrounding alveolar bone were harvested from beagle cadavers. Inclusion criteria included maxillary fourth premolars with no evidence of disease and similar distal root canal volumes on radiographic evaluation. The teeth were randomly divided into a control group and three treatment groups based on the endodontic treatment technique for the palatal root. The control group had a single 2 mm transcoronal access on the mesiobuccal aspect of the tooth to allow instrumentation of both the mesiobuccal and palatal root through a single small access. Alternative treatment modalities that are described for difficult to instrument palatal roots investigated in this study included enlarging the transcoronal mesiobuccal access to 4 mm, making an additional access directly over the palatal root (2 mm), and hemisection with extraction of the palatal root. All teeth had the same distal root access size (2 mm) and relative location. After access, all teeth were filed, shaped, obturated, and restored in the same fashion. Axial compression testing was performed at an angle of 60 degrees to the long axis of the tooth using a universal materials testing machine. The maximum force prior to fracture was determined for each tooth based on a force vs. deflection curve. The mean maximum force prior to fracture for all teeth was 831 N. No significant difference in mean fracture resistance was identified between the control group and treatment groups or between the different treatment groups themselves. Thus, when faced with a difficult to instrument palatal root, the treatment method chosen should be based on operator preference and experience.

The prevalence of traumatic dental injuries in primary teeth: A systematic review and meta-analysis

BACKGROUND/AIMS

The varied prevalence of traumatic dental injuries (TDI) in primary teeth around the globe raises a serious knowledge gap in the available literature. The aim of this study was to evaluate the prevalence of TDI in primary teeth and also to evaluate the different factors associated with TDI in primary teeth.

MATERIALS AND METHODS

Comprehensive searches were performed in PubMed, Embase, Google Scholar, and The Cochrane Central Register of Controlled Trials with predefined search criteria. The primary outcome was the prevalence of TDI in primary teeth, and the secondary outcomes were the factors associated with TDI in primary teeth. Qualitative analysis was done using the Newcastle-Ottawa scale adapted for cross-sectional studies. The random-effect model was used for meta-analysis, and meta-regression analysis was done to evaluate the heterogeneity between the included studies. Meta-analysis was done using the "meta" package of "R" language. The overall quality of evidence was assessed using GRADEpro GDT software.

RESULTS

A total of 24 cross-sectional studies met the inclusion criteria representing 4876 TDIs in 22 839 children aged between 0 and 6 years old. The overall prevalence of TDI in primary teeth was 24.2% (95% CI: 18.24-31.43, P = 0, I²  = 99%). Falls contributed the highest number of TDI - 59.3% (95% CI: 41.05-76.40, P < .01, I²  = 98%) - in primary teeth. The most common type of tooth fracture in primary teeth was an enamel fracture (61.9%), and prevalence of TDI in children with incompetent lip closure was 49.4%.

CONCLUSION

The prevalence of TDI in cross-sectional studies of primary teeth was 24.2% with very low quality of evidence. Falls contributed the highest number of TDI in primary teeth, accounting for 59.3%. Children with incompetent lip closure have the highest prevalence (49.4%) of TDI in primary teeth.

Mouthguard use and attitudes regarding dental trauma among elite cross-country mountain biking and field hockey athletes

BACKGROUND/AIMS

Cross-country mountain biking and field hockey are two Olympic sports that pose a potential risk for dentofacial trauma. However, mouthguard use is not mandatory in either of these sports and knowledge about tooth rescue among athletes is often neglected. The aim of this cross-sectional epidemiological survey was to evaluate the prevalence of sports-related dentofacial injuries, mouthguard use, and attitudes regarding tooth rescue among cross-country mountain biking and field hockey athletes participating at pre-Olympic competitions held in Rio de Janeiro, Brazil.

MATERIALS AND METHODS

A convenience sample of 217 athletes from 33 countries participating in cross-country mountain biking (n = 82; mean age = 30.96 ± 8.52 years) and field hockey (n = 135; mean age = 19.72 ± 2.46 years) pre-Olympic competitions were examined clinically, and they answered a questionnaire regarding previous history of sports-related dentofacial injuries, attitudes toward mouthguard use, and tooth rescue.

RESULTS

There were 120 (55.30%) males and 97 (44.70%) females who participated in the study. The prevalence of facial trauma was higher in mountain biking (54.88%) than in field hockey (26.66%, P < .001). Fracture was the most prevalent facial injury in mountain biking (80%), while laceration was the most prevalent in field hockey (30.55%). Extensive dental injuries occurred more often in mountain biking (47.37%) than in hockey (12.50%). The teeth most often affected were the maxillary central incisors in both mountain biking (57.89%) and field hockey (93.75%). Mouthguard use was more frequent among field hockey athletes (41.48%) than in mountain biking (1.22%, P < .001). The overall knowledge about tooth rescue was low, and most of the athletes in both sports did not know what to do in case of an avulsed tooth.

CONCLUSIONS

Prevalence of dentofacial injuries among XCO-MTB and field hockey athletes participating at this pre-Olympic event was high. The majority of the athletes in this study did not use mouthguards and were unaware of recommendations in the case of an avulsed tooth.

Injury Prevention, Safety Education and Violence in Relation to the Risk of Tooth Fracture among Korean Adolescents

This study aimed to determine the injury prevention-, safety education-, and violence-related factors pertaining to tooth fracture experience (TFE) in Korean adolescents. We used data from the 14th Korea Youth Risk Behavior Survey (KYRBS) in 2018. The 60,040 participants were selected using a complex sampling design from middle and high schools. The participants completed a self-administered questionnaire. The explanatory variables, including school safety education and violence, were assessed in relation to prevention of traumatic injuries. Complex-samples multivariable logistic regression models were applied to explain the factors related to TFE over the past 12 months. The overall prevalence of TFE was 11.4%. Risk factors related to tooth fractures were not wearing a seatbelt on an express bus, not wearing helmets while riding motorcycles and bicycles, clinical treatment due to injuries at school, injuries associated with earphone/smartphones use, and lack of school safety education such as danger evacuation training. The top risk factor was injuries associated with earphone/smartphone usage, followed by lack of familiarity with school safety education. Thus, to prevent tooth fractures among adolescents, schools should strengthen their safety education, including education regarding mobile device usage, and wearing a seatbelt and wearing a helmet. Care should be taken to manage facilities around the school and to prevent injury related to tooth fracture. Further studies on various risk factors related to tooth fractures are warranted.

Prevalence of traumatic dental injuries in India: A systematic review and meta-analysis

Objective

The aim of this systematic review and meta-analysis was to estimate the prevalence of traumatic dental injuries (TDI) in India. The secondary objective was to evaluate the prevalence rate according to the differences in gender, age, regions, type of TDI and risk factors associated with TDI.

Methods

The PubMed, LILACS, Web of Science, Cochrane, CINHAL, and Scopus databases, along with the Public Health Electronic Library, TRoPHI and DoPHER were searched from 1^st March to 15^thApril 2019 without any restriction of language and year of publication. The qualitative synthesis was done regarding the demographics, study methods, cause of trauma, geographic location, increased overjet and inadequate lip coverage. The meta-analysis was undertaken with STATA-14 software (USA). The pooled prevalence of TDI was calculated using data extracted from 48 studies included in qualitative synthesis and meta-analysis. A sub-group meta-analysis was done by extraction of the data for age groups of 6 years and >6 years.

Results

The pooled prevalence of TDI in Indian population was 13 cases in 100 individuals. The prevalence of TDI for age groups of ≤6 was 15% (males, 15%; females, 16%) and for >6 years was 12% (males, 13%; females, 8%). The most common cause of TDI was falls, and most frequent location was home. The odds ratio for occurrence of TDI and inadequate lip-coverage was 3.35 and overjet greater than 3 mm was 3.53.

Conclusions

The pooled prevalence of TDI was 13% and slightly higher in children less than 6 years of age. Inadequate lip coverage and increased overjet are the risk factors associated with TDI. Heterogeneity was observed among the studies in terms of design, variables recorded, sampling, study methods and statistical methods. Majority of them also suffered from moderate to high risk of bias.

Health-Risk Behavior-, Mental Health-, and Physical Exercise-Related Risk Factors for Tooth Fractures in Korean Adolescents

We aimed to determine factors related to tooth fracture experience in Korean adolescents. This study used data from the 14th Korea Youth Risk Behavior Survey in 2018, a cross-sectional web-based survey of health-risk behaviors among a representative sample of Korean middle- and high-school students aged 12–17 years. A total of 60,040 participants were selected using a complex sampling design of the survey from 400 middle schools and 400 high schools. They answered a self-administered questionnaire survey in classrooms. Explanatory variables included those pertaining to health-risk behaviors, mental health, and physical exercise. Complex-sample multivariable logistic regression models were applied to identify factors related to tooth fracture experience in the past 12 months. The overall prevalence of dental fracture experience was 11.4%. Risk factors related to tooth fractures in Korean adolescents were unhealthy behaviors such as alcohol and tobacco consumption; mental health problems including stress, depression, and suicidal ideation; and intensive physical exercise. The major risk factor related to tooth fractures was depression. To prevent tooth fractures among adolescents, schools should strengthen mental health education, encourage mouthguard use during intensive physical exercise, and develop school environments to prevent orofacial injuries. Further studies on various risk factors related to tooth fractures are warranted.

The Incidence of Radiographic Lesions of Endodontic Origin Associated With Uncomplicated Crown Fractures of the Maxillary Fourth Premolar in Canine Patients

Fractured maxillary fourth premolar teeth are commonly diagnosed in canine patients. These fractures are subdivided into uncomplicated and complicated, depending on absence or presence of pulp exposure, respectively. Pulp injury associated with fractures can lead to pulpitis, pulp necrosis, and "lesions of endodontic origin" (LEO) on intraoral radiographs. The incidence of LEO associated with uncomplicated crown fractures (UCFs) of the maxillary fourth premolar in canine patients is currently unknown. We hypothesized that a significant number of UCFs of the maxillary fourth premolar would have LEO evident on intraoral radiographs. The purpose of this article was to identify this incidence and to illustrate the importance of radiographing these teeth. This was a retrospective study of 111 UCFs and 500 nonfractured (control) maxillary fourth premolars in domestic canine patients. The frequency of LEO was 24.3% (27/111) in the UCF population and 0% (0/500) in the control population (P < .0001). These findings are important because UCFs are sometimes ignored or considered insignificant, when in fact a large proportion of them have LEO, indicating periapical pathology. These results suggest that all UCFs be radiographed, even if there are no other abnormalities noted on clinical oral examination.

The International Association of Dental Traumatology ToothSOS mobile app: A 2-year report

BACKGROUND/AIM

The shift in health care and technology calls for innovation through mobile applications as free educational resources for the masses. The International Association of Dental Traumatology (IADT) created ToothSOS, an app (software application for mobile devices) to provide dental trauma information for patients and professionals. The app contains information on the emergency management and prevention of dental injuries, as well as treatment guidelines for dental practitioners. The aim of this study was to assess public utilization of the ToothSOS app in the first 2 years since its launch.

METHODS

The ToothSOS app was launched by the IADT in the first week of April 2018. Data regarding the number of downloads and usage of the app in the first 2 years (from April 2018 to May 2020) were collected and analyzed.

RESULTS

The total number of ToothSOS downloads over the 2 years was 47 725. The number of downloads peaked in the first month when the app was initially released. Thereafter, the number of downloads decreased to an average of 1423 ± 363 downloads every month. Europe was the territory with the greatest number of downloads followed by the United States and Canada, Asia, Latin America and the Caribbean, and Africa, the Middle East, and India.

CONCLUSIONS

Within as short a period as 2 years, the ToothSOS app continues to gain public interest. Further attempts and public campaigns should be made in order to increase the visibility of the app. Dental professionals should encourage patients and communities to use the app in order to increase awareness for the prevention and proper emergency management of traumatic dental injuries.

Management of an Unsuccessful Regenerative Endodontic Procedure after Tooth Fracture: A Case Report

Dental trauma is a very frequent occurrence in children and adolescents, which creates a great impact on the esthetics, functions, and phonetics. Traumatic dental injuries can range from simple enamel fractures to permanent tooth loss. This case report presents an eight-year-old patient with an uncomplicated crown fracture of tooth 21, and 30 days after trauma, it was diagnosed as necrotic pulp. The first treatment choice was a regenerative endodontic procedure (REP), however, the failure led to apexification with Mineral Trioxide Aggregate (MTA). The chosen rehabilitation was a composite veneer. Concerning the available literature and fracture enamel dentin, the treatment approach proposed for the case provided good functional and esthetic outcomes.

Dental injuries at the Xi'an, China Stomatological Hospital: A Retrospective Study

BACKGROUND/AIM

In order to enrich epidemiological knowledge regarding traumatic dental injuries (TDI) in China, and to further improve the treatment, prevention and education of TDI, the aim of this study was to retrospectively analyze the TDI that presented to the emergency dental department at the Stomatological Hospital in Xi'an, China.

METHODS

This retrospective study included all first-visit patients who presented with TDI at the Stomatological Hospital affiliated with the Fourth Military Medical University in Xi'an, China, between January 2013 and June 2019. Data were extracted using the terms of diagnosis of TDI from the hospital database.

RESULTS

Overall, 965 (606 males and 359 females) files were reviewed. The average age was 22.8 ± 13.4 years. Among the 2059 teeth injured (average of 2.1 teeth per patient), the maxillary incisors (1751; 85.0%) were the most prevalent teeth to present with injuries, while the main types of injuries were concussions (14.8%) enamel-dentin-fractures (14.50%) and enamel-dentin-pulp fractures (14.0%). After initial examination and diagnosis, 4.2% patients refused treatment.

CONCLUSIONS

The epidemiological statistics of TDI in Xi'an, China show consistency with other studies from around the world, but they also vary in diagnosis proportion and the choice of treatments. This information may further instruct treatment, prevention and emergency resources distribution to target the high-risk groups.

[Sterilization in dentistry. Limitations of elastic materials: a case presentation]

In everyday dental practice, sterility is essential. Sterilizing different materials can require different methods. In the case of heat sensitive and elastic materials, most common techniques are not suitable because they need to be treated on lower temperature, not to lose their physical properties. For instance, if rubber dam is divested of elasticity, it is useless in restorative dentistry thereafter. Sterilizing rubber dam sheets is not a frequent process, but in certain cases it can be necessary. In such a situation, dentists have to choose between rare and hard-to-reach options. In our referral, we summarize the possibilities of sterilization, focusing on plasma sterilization and hydrogen-peroxide vapor sterilization. During the treatment of our presented case with a deep subgingival fracture line, affecting the crown and the root surface as well, we applied a rubber dam sheet, sterilized with hydrogen-peroxide vapor in order to use adhesive technique. Orv Hetil. 2020; 161(3): 110-115.

Tooth fracture frequency in gray wolves reflects prey availability

Exceptionally high rates of tooth fracture in large Pleistocene carnivorans imply intensified interspecific competition, given that tooth fracture rises with increased bone consumption, a behavior that likely occurs when prey are difficult to acquire. To assess the link between prey availability and dental attrition, we documented dental fracture rates over decades among three well-studied populations of extant gray wolves that differed in prey:predator ratio and levels of carcass utilization. When prey:predator ratios declined, kills were more fully consumed, and rates of tooth fracture more than doubled. This supports tooth fracture frequency as a relative measure of the difficulty of acquiring prey, and reveals a rapid response to diminished food levels in large carnivores despite risks of infection and reduced fitness due to dental injuries. More broadly, large carnivore tooth fracture frequency likely reflects energetic stress, an aspect of predator success that is challenging to quantify in wild populations.

Gray wolves roam many European and American landscapes, where they prey on large animals such as elk and moose. A healthy dentition is essential for these predators to kill, eat and defend themselves. As a result, they tend to avoid biting down on tough body parts, such as bones, so that their teeth do not break. If food becomes scarce however, the wolves may resort to consuming these hard elements, eating more of the carcasses and leading to more damaged teeth. It could therefore be possible to assess the food levels available to existing (or even extinct) wolf populations based on how many broken teeth the animals have. However, older individuals are also more likely to have more damaged teeth, so age would need to be taken into consideration.

Van Valkenburgh et al. decided to evaluate whether it was indeed possible to deduce how much food was available to groups of wolves based on teeth damage. Tooth wear and fracture were quantified in three current populations of gray wolves whose skulls had been collected and preserved in natural history collections. For each group, there were data available about the variations of number of moose per wolf over time, and how much of the carcasses the wolves were consuming. The analyses showed that indeed, when prey became less abundant, the wolves ate more of the remains – including the bones – and therefore broke more teeth.

These conclusions can be applied to other large predators and even to extinct species such as dire wolves or sabertooth cats. Tapping into the potential of museum specimens could help to retrace environmental conditions and the history of animals now long gone.

Endodontically treated posterior teeth restored with or without crown restorations: A 5-year retrospective study of survival rates from fracture

AIM

The aim of the present study was to investigate survival rates from fracture of endodontically treated posterior teeth (ETT) restored with or without crowns with recall periods of up to 5 years.

METHODS

ETT with single-unit crown or resin composite restorations were studied based on the inclusion criteria. Restoration, tooth structure loss, adjacent teeth, fracture, and restorability were recorded. Survival rates from fracture were calculated, and risk factors were identified.

RESULTS

Overall, survival rate of ETT with crowns (92.2%) was significantly higher than resin composites (77.4%) (P < 0.05). ETT with one or two surface loss/es and two adjacent teeth had a high survival rate of 86.9%, which was not significantly different to ETT with crowns (P ≥ 0.05). Restoration and adjacent teeth were identified as significant factors. The majority of fractured ETT with resin composites were restorable, whereas those with crowns were unrestorable. Survival rates from unrestorable fracture were not significantly different between the crown (93.1%) and resin composite (96%) (P ≥ 0.05).

CONCLUSIONS

The survival rate from the fracture of ETT restored with crowns was significantly higher than ETT restored with resin composites, but was not significantly different to ETT with one or two ETT with one or two surface loss/es and two adjacent teeth. ETT restored with resin composites had mostly restorable fracture, whereas ETT with unrestorable fracture were similar between the two restorations.

Evaluation of the influence of various restoration techniques on fracture resistance of endodontically treated teeth with different cavity wall thicknesses

AIMS

The aim of this study was to compare the effect of different restoration techniques on fracture resistance of endodontically treated teeth with different wall thicknesses.

MATERIALS AND METHODS

Extracted and endodontically treated 210 premolars were randomly divided into three thickness groups [2 mm (A), 1.5 mm (B), and 1 mm (C)] and, each group was further divided into seven restoration subgroups (n = 10): direct composite (control) (K), composite with fiber on cavity floor (KT), composite with fiber on occlusal level (KO), fiber post and composite (FP), inlay (L), fiber on cavity floor and inlay (LT), and inlay and fiber on occlusal level (LO). Fracture test was performed, and data were compared with Kruskal-Wallis and Mann-Whitney U tests (P < 0.05).

RESULTS

There were no differences between the subgroups in A and C statistically (P > 0.05). However, in B, KO subgroup showed statistically higher values (P = 0.039).

CONCLUSION

Wall support of 2 mm was adequate, and support of 1 mm was completely insufficient. When the wall thickness was 1.5 mm, direct restoration with fiber at the occlusal level significantly improved resistance.

Fracture Limits of Maxillary Fourth Premolar Teeth in Domestic Dogs Under Applied Forces

A cadaveric study was performed to investigate the external mechanical forces required to fracture maxillary fourth premolar teeth in domestic dogs and describe a clinically relevant model of chewing forces placed on functionally important teeth in which fracture patterns are consistent with those defined by the American Veterinary Dental College (AVDC). Twenty-four maxillary fourth premolar teeth were harvested from dog cadavers. Samples consisted of teeth with surrounding alveolar bone potted in polycarbonate cylinders filled with acrylic. The cylinders were held by an aluminum device at an angle of 60° with respect to the ground. An axial compression test was performed, creating a force upon the occluso-palatal aspects of the main cusps of the crowns of the teeth. The highest compressive force prior to failure was considered the maximum force sustained by the teeth. Results showed the mean maximum force (± SD) sustained by the tested teeth at the point of fracture was 1,281 N (± 403 N) at a mean impact angle (± SD) of 59.7° (± 5.2°). The most common fracture type that occurred among all samples was a complicated crown fracture (n = 12), followed by an uncomplicated crown fracture (n = 6), complicated crown-root fracture (n = 5), and uncomplicated crown-root fracture (n = 1). There was no statistically significant correlation between dog breed, age, weight, impact angle, crown height or crown diameter, and the maximum force applied at the point of fracture. The only independent variable that remained significantly associated with maximum force was the crown height to diameter ratio (p = 0.005), suggesting that a decreased ratio increases tooth fracture resistance. The methodology described herein has been successful in creating a pattern of fracture of maxillary fourth premolar teeth consistent with that defined by the AVDC under angled compression at forces within the maximum chewing capability of the average domestic dog.

Impact of crown fracture treatment on oral health-related quality of life of children, adolescents, and their families: A prospective clinical study

BACKGROUND

Enamel-dentin fracture causes impact on the oral health-related quality of life (OHRQoL) of children.

AIM

To evaluate the impact of treatment of crown fracture involving enamel and dentin (CFED) in the permanent dentition on the OHRQoL of children and adolescents (C/As) and their families.

DESIGN

This prospective clinical study included C/As between 8 and 14 years who presented anterior CFED treated thought direct composite resin restoration. Their parents/caregivers (P/Cs) were also invited to take part of the study. The quality of life was evaluated thought the Child Perceptions Questionnaires (CPQ_8-10  and CPQ_11-14 ), Parental-Caregiver Perceptions Questionnaire (P-CPQ), and Familiar Impact Scale (FIS), applied before and 3 months after the restorative procedure. T test for dependent samples and Wilcoxon test were applied(P < 0.05).

RESULTS

Of 32 C/As included, 30 completed the study. The treatment of CFED reduced the negative impact in OHRQoL of C/As (CPQ_8-10 P = 0.0065; CPQ_11-14 P = 0.0486; P-CPQ, P = 0.0259), specially for "oral symptoms" (CPQ_8-10 , P = 0.0003; P-CPQ, P = 0.0455) and "emotional well-being" (CPQ_11-14 , P = 0.0431). Concerning the families' perceptions, the treatment did not influence OHRQoL both in terms of the domains and total FIS score (P > 0.05).

CONCLUSION

Restorative treatment of CFED increases the OHRQoL of C/As but not influence the OHRQoL of their families.