Dissecting dentine-pulp injury and wound healing responses: consequences for regenerative endodontics.

A thorough understanding of the biology of the dentine-pulp complex is essential to underpin new treatment approaches and maximize clinical impact for regenerative endodontics and minimally invasive vital pulp treatment (VPT) strategies. Following traumatic and carious injury to dentine-pulp, a complex interplay between infection, inflammation and the host defence responses will occur, which is critical to tissue outcomes. Diagnostic procedures aim to inform treatment planning; however, these remain clinically subjective and have considerable limitations. As a consequence, significant effort has focussed on identification of diagnostic biomarkers, although these are also problematic due to difficulties in identifying appropriate diagnostic fluid sources and selecting reproducible biomarkers. This is further compounded by the link between inflammation and repair as many of the molecules involved exhibit significant multifunctionality. The tertiary dentine formed in response to dental injury has been purposefully termed reactionary and reparative dentine to enable focus on associated biological processes. Whilst reactionary dentine produced in response to milder injury is generated from surviving primary odontoblasts, reparative dentine, in response to more intense injury, requires the differentiation of new odontoblast-like cells derived from progenitor/stem cells recruited to the injury site. These two diverse processes result in very different outcomes in terms of the tertiary dentine produced and reflect the intensity rather than specific nature (nonexposure versus exposure) of the injury. The subsequent identification of the odontoblast-like cell phenotype remains challenging due to lack of unique molecular or morphological markers. Furthermore, the cells ultimately lining the newly deposited dentine provide only a snapshot of events. The specific source and plasticity of the progenitor cells giving rise to the odontoblast-like cell phenotype are also of significant debate. It is likely that improved characterization of tertiary dentine may better clarify the influence of cell derivation for odontoblast-like cells and their diversity. The field of regenerative endodontics offers exciting new treatment opportunities, and to maximize outcomes, we propose that the term regenerative endodontics should embrace the repair, replacement and regeneration of dentine-pulp.

Activation of αSMA expressing perivascular cells during reactionary dentinogenesis.

AIM: To examine the contribution of perivascular cells expressing αSMA to reactionary dentinogenesis. METHODOLOGY: An inducible, Cre-loxP in vivo fate-mapping approach was used to examine the contribution of the descendants of cells expressing the αSMA-CreERT2 transgene to reactionary dentinogenesis in mice molars. Reactionary dentinogenesis was induced by experimental mild injury to dentine without pulp exposure. The Student's t test was used to determine statistical significance at *P ≤ 0.05. RESULTS: The lineage tracing experiments revealed that mild injury to dentine first led to activation of αSMA-tdTomato+ cells in the entire pulp chamber. The percentage of areas occupied by αSMA-tdTomato+ in injured (7.5 ± 0.7%) teeth were significantly higher than in teeth without injury (2 ± 0.5%). After their activation, αSMA-tdTomato+ cells migrated towards the site of injury, gave rise to pulp cells and a few odontoblasts that became integrated into the existing odontoblast layer expressing Col2.3-GFP and Dspp. CONCLUSION: Mild insult to dentine activated perivascular αSMA-tdTomato+ cells giving rise to pulp cells as well as a few odontoblasts that were integrated into the pre-existing odontoblast layer.

Effects of ultrasonic removal of fractured files from the middle third of root canals on dentinal cracks: a micro-computed tomography study.

AIM: To evaluate the frequency of dentinal microcracks after ultrasonic removal of fractured files from the middle third of root canals using micro-computed tomography (micro-CT). METHODOLOGY: Eighteen bilaterally matched pairs of human mandibular incisors extracted for periodontal reasons were included. The matched pairs of teeth were then divided into a control group and an experimental group, with one member of each pair assigned to each group. In the control group, the canals were instrumented using the ProTaper Next (PTN) system. In the experimental group, size 20 K-files were fractured in the middle third of the root canals, followed by their ultrasonic removal. Subsequently, the canals were instrumented with the PTN system. All teeth were scanned using high-resolution micro-CT before (preoperative) and after (intraoperative) file removal and after (postoperative) root canal preparation. Pre-, intra-, and postoperative cross-sectional images of the roots were screened to identify the presence of dentinal defects. Two experienced observers evaluated the images twice in a blinded manner. The incidence of dentinal microcracks was noted and statistically analysed using Fisher's exact and McNemar's tests (P = 0.05), with the root cross-section and the tooth root as the units of analysis, respectively. RESULTS: All fractured files in the experimental group were removed successfully. New microcracks were detected in 0.56% (93/16 472) cross-sections (8/18 specimens) generated after file removal in the experimental group. These microcracks were detected 4-6 mm below the root canal orifice and exhibited a width and length of 12-36 µm and 48-72 µm, respectively. They did not disappear or propagate after canal preparation. No new dentinal microcracks were observed in the control group. There was a significant difference in the incidence of new microcracks between the two groups (P < 0.05). CONCLUSIONS: Ultrasonic removal of fractured files from root canals resulted in the formation of short microcracks in a small number of cross-sections in approximately half the specimens. Further studies are necessary to determine the cause and consequences of this finding.

Micro-CT assessment of dentinal micro-cracks after root canal filling procedures.

AIM: To evaluate the frequency of dentinal micro-cracks after root canal filling procedures with GuttaCore (GC), cold lateral compaction (CLC) and warm vertical compaction (WVC) techniques in mandibular molars using micro-computed tomographic analysis. METHODOLOGY: Thirty mesial roots of mandibular molars, with a type II Vertucci's canal configuration, were prepared to working length with a Reciproc R40 instrument and randomly assigned to one of the three experimental groups (n = 10), according to the technique used for root filling: GC, CLC or WVC. The GC group was filled with a size 40 GC obturator, whilst CLC and WVC groups used conventional gutta-percha cones. AH Plus sealer was used in all groups. The specimens were scanned at an isotropic resolution of 14.25 µm before and after root canal preparation and after root filling. Then, all pre- and postoperative cross-sectional images of the roots (n = 41 660) were screened to identify the presence of dentinal defects. RESULTS: Overall, 30.75% (n = 12 810) of the pre- + post-filling images displayed dentinal defects. In the GC, CLC and WVC groups, dentinal micro-cracks were observed in 18.68% (n = 2510), 15.99% (n = 2389) and 11.34% (n = 1506) of the cross-sectional images, respectively. All micro-cracks identified in the post-filling scans were also observed in the corresponding post-preparation images. CONCLUSION: Root fillings in all techniques did not induce the development of new dentinal micro-cracks.

Occurence of dentinal defects after root canal preparation with R-phase, M-Wire and Gold Wire instruments: a micro-CT analysis.

BACKGROUND: This study aims to evaluate the frequency of dentinal defects after root canal preparation with the ProTaper NEXT, K3XF and WaveOne GOLD systems using microcomputed tomography. METHODS: Sixty permanent mandibular incisors with a single canal were selected. Inspection of the teeth was performed under a stereomicroscope (15x) to observe the presence of pre-existing cracks and fractures lines. Samples were divided into three experimental groups (n = 20): ProTaper NEXT (PTN), K3XF (K3XF) and WaveOne GOLD (WOG). Specimens were scanned through high-resolution microcomputed tomography before and after the preparation of the root canal. Subsequently, all the axial images were examined by two different methods to find possible dentinal defects. Furthermore, an analysis of each millimeter of ten apical millimeters was also performed. The absence or presence of dentinal defects was screened by 3 pre-calibrated blinded examiners. RESULTS: After analysing all 45,720 slices, dentinal defects were observed in 48,33% (22096 slices). PTN, K3XF and WOG groups represented 11,11% (5079 slices), 17,22% (7873 slices) and 20% (n = 9144) of the cross-sectional images, respectively. At 10 apical millimeters (600 slices), 33,33% (200 slices) presented some dentinal defects, representing 7,22% (43 slices), 13,33% (80 slices) and 12,77% (77 slices) of the cross-sectional images in the PTN, K3XF and WOG groups, respectively. All the dentinal defects presented in the postoperative images existed in the images prior to instrumentation. CONCLUSIONS: There was no correlation between the preparation of a root canal using the PTN, K3XF and WOG systems and the formation of new dentinal defects.

The compression dome concept: the restorative implications.

Evidence now supports the concept that the enamel on a tooth acts like a compression dome, much like the dome of a cathedral. With an overlying enamel compression dome, the underlying dentin is protected from damaging tensile forces. Disruption of a compression system leads to significant shifts in load pathways. The clinical restorative implications are significant and far-reaching. Cutting the wrong areas of a tooth exposes the underlying dentin to tensile forces that exceed natural design parameters. These forces lead to crack propagation, causing flexural pain and eventual fracture and loss of tooth structure. Improved understanding of the microanatomy of tooth structure and where it is safe to cut teeth has led to a revolution in dentistry that is known by several names, including microdentistry, minimally invasive dentistry, biomimetic dentistry, and bioemulation dentistry. These treatment concepts have developed due to a coalescence of principles of tooth microanatomy, material science, adhesive dentistry, and reinforcing techniques that, when applied together, will allow dentists to repair a compromised compression dome so that it more closely replicates the structure of the healthy tooth.

Effect of Sodium Hypochlorite on Push-out Bond Strength of Four Calcium Silicate-based Endodontic Materials when used for repairing Perforations on Human Dentin: An in vitro Evaluation.

AIM: This study aimed to evaluate the push-out bond strength of NeoMTA Plus (NMTA), EndoSequence root repair material fast set putty (ERRMF), biodentine (BD), and ProRoot white mineral trioxide aggregate (PMTA) when used as perforation repair materials after exposure to 2.5% sodium hypochlorite (NaOCl) during the early setting phase. MATERIALS AND METHODS: Horizontal midroot sections were prepared from single-rooted human teeth. Sections (n = 144) were randomly divided into four groups: PMTA, BD, NMTA, and ERRMF. Materials were condensed and allowed to set for 10 minutes. The groups were further divided into two subgroups. The NaOCl group included specimens that were immersed in 2.5% NaOCl for 30 minutes, and the control group included specimens on which a wet cotton pellet was placed over the test material. After 48 hours, the highest force applied to the materials at the time of dislodgement was recorded. Slices were then examined under a digital microscope to evaluate the nature of the bond failure. The surfaces of two specimens from each subgroup were observed by scanning electron microscopy. Data were statistically analyzed with two-way and one-way analysis of variances, independent t-tests, and chi-square tests. The statistical significance was set at 0.05. RESULTS: In NaOCl-treated groups, PMTA showed a significantly higher push-out bond strength than the other three materials (p = 0.00). In the control groups, the bond strength of BD was significantly higher than that of PMTA, ERRMF, and NMTA (p < 0.05). Compared with the control group, NaOCl treatment significantly increased the push-out bond strength of PMTA (p = 0.00) and ERRMF (p = 0.00) and significantly reduced the bond strength of BD (p = 0.00) and NMTA (p = 0.03). None of the specimens showed an adhesive type of failure. The majority of the samples exhibited a cohesive failure type. Morphological observations revealed that the surfaces exhibited cubic crystals. In ERRMF, the crystals were few in number. Sodium hypochlorite enhanced the crystallization of NMTA. CONCLUSION: The push-out bond strengths of PMTA and ERRMF were significantly increased after exposure to 2.5% NaOCl in the early setting phase, and those of BD and NMTA were significantly decreased. CLINICAL SIGNIFICANCE: The results of the present study suggest that early exposure of NaOCl increase the push-out bond strength of PMTA and ERRMF. PMTA had the highest push-out values. Therefore, it would be a potentially useful perforation repair material for single visit endodontic treatment.

[Effect of low intensity pulsed ultrasound on expression of TGF-ß1 and Smads during dentin injury and repair].

OBJECTIVE: To explore the effect of low intensity pulsed ultrasound (LIPUS) on TGF-ß1/Smad 2, 3 signal pathway during the dentin injury and repair.
 Methods: Among 25 Sprague-Dawley rats, 5 rats served as a blank control group without treatment. The remaining 20 rats received modified caries preparation inbilateral maxillary first molars to establish a model of dentin-pulp injury and repair. The right maxillary first molars served as a LIPUS group, which received LIPUS irradiation (frequency: 1.5 MHz, pulse width: 200 µs, pulse repetition frequency: 1 kHz, spatial averaged temporal averaged intensity: 30 mW/cm2, 20 min/d), and the left maxillary first molars served as a cavity-prepared group, which received fake LIPUS irradiation. The rats were sacrificed at 1, 3, 5, 7 and 14 days after LIPUS irradiation. Immunohistochemical staining and Image-pro plus 6.0 were applied to detect the expression and distribution of transforming growth factor-beta1 (TGF-ß1) and small mothers against decapentaplegic 2/3(Smad 2 and Smad 3).
 Results: Immunohistochemical staining showed that the expression of TGF-ß1 and Smad 2, 3 were low innormal pulp, but they were increased in different degree after dentin injury. The result of image analysis showed that the expression of TGF-ß1 in the cavity-prepared group gradually increased at the first day and peaked at day 5, and then it returned to normal level at day 14. However, the expression of TGF-ß1 in the LIPUS group were significantly higher than that in the cavity-prepared group at day 3 and 5 (both P<0.05). The expressions of Smad 2,3 in both the LIPUS group and the cavity-prepared group were consistently increased all the way, but the expressions in the LIPUS group were higher compared with that in the cavity-prepared group (P<0.05).
 Conclusion: The TGF-ß1/Smad 2, 3 signal pathway can be activated during the dentin injury and repair. LIPUS can up-regulate the expression of TGF-ß1 and Smad 2, 3 in the early period, which may take part in the dentin-pulp complex injury and repair process.

Incidence of dentinal defects after preparation of severely curved root canals using the Reciproc single-file system with and without prior creation of a glide path.

AIM: To investigate the incidence of dentinal defects after preparation of severely curved root canals using the Reciproc single-file system with and without prior creation of a glide path. METHODOLOGY: Mesial roots from extracted mandibular first molars were collected and scanned with CBCT to assess the morphology of the root canal systems. Three groups of 20 anatomically comparable specimens were generated. The control group was left unprepared, whilst the experimental groups were prepared with Reciproc R25 with and without a glide path (groups RG and R, respectively). Roots were then sectioned perpendicular to the long axis at 2, 4, 6, 8 and 10 mm from the apex, and coloured photographs of the sections at 40× were obtained. Two blinded examiners registered the presence of dentinal defects twice at 2-week interval. Data were statistically analysed using the Fisher exact and Cochran's Q tests. RESULTS: No defects were observed in the control group. The overall incidence of dentinal defects was 26% in group R and 24% in group RG, with no significant differences between them (P > 0.05). Dentinal defects occurred significantly more often in the middle and coronal thirds compared to the apical third of the canals (P < 0.05). CONCLUSIONS: Prior preparation of a glide path had no impact on the incidence of dentinal defects when using Reciproc files.

Comparison of ProTaper, RaCe and Safesider instruments in the induction of dentinal microcracks: a micro-CT study.

AIM: To evaluate ex vivo the incidence of microcracks in root dentine after canal preparation with ProTaper Universal (PTU), RaCe or Safesider instrumentation systems using microcomputed tomography (micro-CT). METHODOLOGY: Thirty freshly extracted mandibular molars with two separate mesial canals and foramina were used. The roots were allocated into three similar groups according to curvature angles and radii of the canals and lengths of the roots. Distal roots were removed and mesial roots were embedded in acrylic resin and instrumented with the PTU, RaCe or Safesider systems up to size 30 (F3 for PTU, size 30, 0.04 taper for RaCe and Safesider) for all instrumentation groups. Dentinal microcracks were evaluated on micro-CT images of the apical 10 mm of the roots with 1-mm intervals. Two experienced observers evaluated the images twice in a blinded fashion. The presence of dentinal microcracks (complete/incomplete cracks and craze lines) was noted and analysed statistically using McNemar and chi-square tests (P = 0.05). RESULTS: There were microcracks on uninstrumented root sections. All instrumentation systems significantly increased the number of dentinal microcracks when compared to preoperative specimens (P < 0.05). There were new microcracks on the postoperative samples. The PTU system (42%) led to greater number of post-instrumentation microcracks than Safesider (35%) and RaCe (25%) systems, respectively. The difference between PTU and RaCe system was significant (P < 0.05). CONCLUSIONS: All instrumentation systems significantly increased the number of microcracks compared with preoperative specimens. The PTU system generated more post-instrumentation dentinal microcracks than the RaCe system.

Cross-sectional Study of Dental Trauma and Associated Factors Among 9- to 14-year-old Schoolchildren in Isfahan, Iran.

PURPOSE: To assess the prevalence of dental trauma (DT) and its associated factors in 9- to 14-year-olds. SUBJECTS AND METHODS: A cross-sectional survey was carried out through clinical examination of the permanent incisors and canines of 907 schoolchildren (9 to 14 years old, average age = 11 ± 0.5 [SD] years, 55% female and 45% male) enrolled in 20 public schools in Isfahan, Iran. The demographic data, history and cause of trauma were recorded during patient interviews and with a structured questionnaire filled in by their parents. The overjet, lip coverage, and visible signs of DT (permanent incisors only, similar to the classification used by the US National Health and Nutrition Examination Survey 1988-1994, NHANES III) were recorded. DT in permanent canines were also recorded. RESULTS: Approximately 36% (n = 325) recalled the occurrence of dental trauma, but only 23.8% (n = 216) of children had visible signs of dental trauma to the permanent incisors (girls [18.8%], boys [29.9%], OR = 0.54; 95% CI 0.40- 0.74; p = 0.000). The maxillary central incisors were commonly injured (69.5%). The most frequent types of injuries were the enamel fracture (59.0%), craze lines (16.3%), and enamel and dentin fracture (13.4%). Tooth avulsion was seen in 0.7%. No significant association was found between dental trauma and increased overjet of > 3 mm (p = 0.328), but a tendency was identified for overjet > 5 mm (OR = 1.51; 95% CI 0.89-2.58; p = 0.060). The relationship between DT and lip coverage was statistically significant (OR = 1.63; 95% CI 1.18-2.25; p = 0.003). Violence (30%) and fall (22.7%) were the main causes of DT. CONCLUSION: The prevalence of DT in permanent incisors was high (23.8%) and significantly lower in girls. The association between DT and lip coverage was significant. There was no association between DT and increased overjet of > 3 mm.

[Risk factors for vertical root fractures after endodontic treatment]. / Faktory riska vozniknoveniia vertikal'nykh treshchin kornia v zubakh posle éndodonticheskogo lecheniia.

The review sought to describe the main risk factors for vertical root fracture predisposition in teeth after root canal treatment: altered mechanical characteristics of dentine due to loss of moisture and use of aggressive irrigation agents, insufficient amount of remaining dentine tissue after mechanical preparation of root canals, damage to the remaining tooth structure due to the effects of posts of different materials. According to the reviewed studies it is difficult to reveal the main factor predisposing to vertical root fractures. It is likely that in each case there is an interaction of several factors.

The effect of reciprocation versus rotational movement on the incidence of root defects during retreatment procedures.

AIM: To compare the incidence of dentinal defects caused by reciprocating and rotary techniques during retreatment procedures. METHODOLOGY: One hundred and twenty extracted mandibular premolars with single canals were selected. Twenty teeth were left unprepared. The root canals in the remaining 100 teeth were prepared with K-files up to size 35 and filled with Gutta-percha and AH Plus sealer using a passive cold lateral compaction technique. Twenty canals were filled and received no further treatment. Eighty teeth were divided into four groups (n = 20 in each) to undergo the removal of the root filling. In groups 1 and 2, the root filling was removed using ProTaper Retreatment files and Reciproc files, respectively, and the canals were not refilled. In groups 3 and 4, the root filling was removed using ProTaper Retreatment files and Reciproc files, respectively, and the canals were then refilled using a conventional cold lateral compaction technique. The roots were sectioned horizontally at 3, 6 and 9 mm from the root apex and observed under a stereomicroscope at 20× magnification. Defects were categorized as no defect, incomplete defect and fracture. The differences between the groups were analysed using the chi-square exact test (P = 0.05). RESULTS: No defects were observed in the unprepared and filled groups, in contrast to the experimental groups. In the coronal thirds, groups 2 and 4 had more dentinal defects than groups 1 and 3 (P < 0.05). In the middle thirds, group 4 had more defects than group 1 (P < 0.05). In the apical thirds, group 2 had fewer defects than did group 3 and group 4. Also, group 3 had more defects than group 1 (P < 0.05). When comparing the experimental groups, there were no significant differences with regard to fracture (P > 0.05). CONCLUSIONS: Both nickel-titanium systems were associated with dentinal defects during retreatment procedures in extracted premolar teeth.

Synchrotron light-based µCT to analyse the presence of dentinal microcracks post-rotary and reciprocating NiTi instrumentation.

OBJECTIVES: The purpose of this study was to determine in vitro using a synchrotron radiation-based µCT (SRCT) whether rotary and reciprocating nickel titanium (NiTi) instrumentations lead to the formation of dentine microcracks. MATERIAL AND METHODS: Fourteen extracted human molars were obtained with ethical approval. Seven distobuccal roots of the maxillary molars and seven mesial roots of the mandibular molars were assigned to two experimental groups: (A) prepared with rotary Pro Taper instrumentation (n = 6) and (B) reciprocating WaveOne (n = 6). Irrigation with 1 % NaOCl and 17 % EDTA solutions was carried out. The remaining roots served as positive control with induced fractures (group C). SRCT was used to scan all samples pre and post-operatively. An imaging software was used to determine the number and length of microcracks. Statistical analyses weighed differences between pre and post-instrumentation and between shaping methods. RESULTS: A significant increase in the number and length of microcracks was detected post-shaping. No significant difference between rotary and reciprocating instrumentation was observed. CONCLUSIONS: Within the limitations of this in vitro study, an increased number and length of microcracks was induced by mechanical instrumentation. Reciprocating and rotary instrumentation are similar in terms of effect. CLINICAL SIGNIFICANCE: Dentinal damage may occur following rotary and reciprocating instrumentation.

Are behaviour risk factors for traumatic dental injuries in childhood different between males and females?

AIM: Examination of the risk factors for childhood traumatic dental injuries for male and female patients have been elusive. The present study aimed to examine whether males and females are differentially vulnerable to Traumatic Dental Injuries in relation to emotion regulation, attention deficiency hyperactive disorder symptomatology and behaviour problems. MATERIALS AND METHODS: An institutional ethical review board approved the case-control study carried out at the Gazi University, Faculty of Dentistry, Turkey. A total of 80 patients with traumatic dental injuries and 80 patients with other dental problems participated in the study. Patients' parents filled in two scales: Conners' Rating Scales-Revised Attention Deficiency Hyperactive Disorder-Index, Oppositional Behavior, Hyperactivity, Anxious-Shy, Social Problems, Inattentive and Hyperactive-Impulsive subscales; and Emotion Regulation Checklist, with two subscales of Emotional Lability and Emotion Regulation. Multiple logistic regression analyses were performed separately for male and female patients. RESULTS: Oppositional behaviour, hyperactivity and social problems were found to be risk factors for male patients. Being anxious/shy was the protective factor for both males and females. Classification accuracy for males and females were calculated to be 79.2% and 85.2% respectively. CONCLUSION: Several risk factors for childhood traumatic dental injuries were found to differ for male and female patients.

Sealing Ability of Four Calcium Containing Cements used for Repairing Furcal Perforations in Primary Molars: An in vitro study.

AIM: The aim of this study was to compare the sealing ability of mineral trioxide aggregate (MTA), Portland cement (PC), Biodentine(TM) and Tech biosealer in repairing furcal perforations in primary molars using the fluid-filtration technique. MATERIALS AND METHODS: Fifty freshly extracted maxillary second primary molars were sectioned horizontally at the furcation region to create dentin disks of 1.5 mm (+ 0.1 mm) thickness. Five disks were not perforated and served as negative controls. In the remaining 45 disks, furcation perforations were prepared. Five disks did not receive furcation repair and served as positive controls. The remaining 40 disks were then randomly divided into four equal groups (10 disks in each group). Perforations were repaired with: MTA, PC, Biodentine(TM) or Tech Biosealer. The sealing ability of the tested materials was evaluated by measuring microleakage for each disk after four different storage periods: 24-hour, 1-month, 6-month and 1-year storage using fluid-filtration. Comparisons between the four materials and the four time periods were done using the two-way analysis of variance and the Scheffe multiple comparisons test. RESULTS: There was no significant difference between the mean microleakage values obtained in the four tested materials after 24 hours, 1, 6 month and 1 year. However, microleakage values for each individual material were significantly higher at 24 hours than at the other time intervals. CONCLUSION: Mineral trioxide aggregate, PC, Biodentine(TM) and Tech biosealer showed similar capabilities in sealing the furcal perforations of the primary molars, where the sealing ability improved over time for each individual material.

Classification and Epidemiology of Traumatic Dentoalveolar Injuries in Dogs and Cats: 959 Injuries in 660 Patient Visits (2004-2012).

The objective of this study was to determine the epidemiology of traumatic dentoalveolar injuries (TDI) in dogs and cats and to evaluate the applicability of a human classification system for TDI in dogs and cats. All patients diagnosed with a TDI were identified from the University of Wisconsin-Madison School of Veterinary Medicine Dentistry and Oral Surgery Service case log and the hospital patient processing software. The study population consisted of 621 dogs and cats, in a total of 660 patient visits from 2004 to 2012, admitted for oral treatment and subsequently diagnosed with at least one TDI Medical records including diagnostic imaging studies were reviewed to group the injury according to a classification system used in humans for TDI. Patient signalment, tooth injured, and number of injuries per patient were recorded and tabulated. The overall prevalence of TDI was 26.2%. The mean +/- SD number of TDI per patient was 1.45 +/- 0.85. All 14 classes of TDI recognized by the classification system utilized in humans were identified, and all (100%) TDI identified in this study were classifiable using this system. Enamel-dentin-pulp fracture was the most common TDI (49.6%). The most commonly injured teeth were the mandibular or maxillary canine teeth (35.5%). The most common age for dogs and cats with TDI were 3-6 years (33.0%) and 7-10 years (31.3%). With a frequency of 1 in 4 animals, TDI are common and represent a significant pet health concern. Most TDI are considered severe and require timely, and sometimes immediate, treatment. The adoption and utilization of a complete classification system, such as the one used in this study, is recommended in order to improve future epidemiological study of TDI in animals.

Prevalence and unmet treatment need of traumatized incisor among Cameroonian schoolchildren in North West Province.

OBJECTIVE: To determine the prevalence and unmet treatment need of traumatized incisor in 12-13 years old among Cameroonian Schoolchildren in the North West Province. MATERIALS AND METHODS: This cross-sectional survey among 12-13 years old children of selected rural and urban secondary schools in North West province of Cameroon was conducted between March and November, 2010. RESULTS: The majority of the 2287 studied children were females (50.2%) and urban dwellers (51.8%). Of the 2287 studied children, 45 of them exhibited evidence of incisor trauma giving a prevalence of 2.0%. This prevalence was higher in males than females (2.3% versus 1.7%) and also higher in urban than rural schools (2.2% versus 1.7%). Upper central incisor was the predominantly traumatized tooth and enamel fracture constituted 62.2% of incisor trauma. Fall and sports were the leading cause of incisor trauma in this study. Some minor variations in the causes of incisor trauma were found among gender and location. The prevalence of unmet treatment need was 91.1% which were mainly acid etch restoration. Males and rural dwellers had more unmet treatment need. CONCLUSION: Data revealed a low prevalence of traumatized incisor with high prevalence of unmet treatment needs among Cameroonian Schoolchildren in North West Province. Findings of this survey provide baseline information on prevalence and unmet treatment need for traumatized incisor among Cameroonian Schoolchildren in the North West Province.

Effects of the bisphosphonate alendronate on molars of young rats after lateral luxation.

BACKGROUND AND AIM: The bisphosphonate alendronate (ALN) was employed with the aim of investigating its effects on dental and periodontal tissues after lateral luxation of developing molars. MATERIAL AND METHODS: Twenty-one-day-old Wistar rats had their second upper molars laterally luxated. Daily 2.5 mg kg(-1) ALN injections started at the day of the luxation; controls received sterile saline solution. The teeth were analyzed 7, 14, and 21 days after the procedure. On the days cited, the maxillae were fixed, decalcified, and embedded in paraffin or Spurr resin. The paraffin sections were stained with H&E, incubated for TRAP histochemistry or immunolabeled for osteopontin (OPN). Spurr ultrathin sections were examined in a transmission electron microscope. RESULTS: After 21 days, the root apex of luxated molars without ALN was wide open and disorganized and also covered by an irregular layer of cellular cementum, which was not observed in ALN-treated animals. Ankylosis sites were observed in ALN rats in both luxated and non-luxated teeth. The TRAP-positive osteoclasts were more numerous in ALN group, despite their latent ultrastructural appearance without the presence of resorption apparatus compared to controls. OPN immunolabeling revealed a thick immunopositive line in the dentin that must be resultant from the moment of the luxation, while ALN-treated specimens did not present alterations in dentin. CONCLUSION: The present findings indicate that alendronate inhibits some alterations in dentin and cementum formation induced by dental trauma.

Traumatic dental injuries among 12-year-old Jordanian schoolchildren: an investigation on obesity and other risk factors.

BACKGROUND: Traumatic dental injury (TDI) is an important public dental health problem among schoolchildren. The aim of the study was to investigate the relationship between TDIs, obesity, and other possible associated factors like gender, overjet, lip coverage, parents' education level and family income among 12-year old Jordanian schoolchildren. METHODS: A cross-sectional population-based study examined a total of 1015 schoolchildren attending 34 schools randomly selected from urban and rural areas of Amman-the capital city of Jordan. The epidemiological classification adopted by WHO and modified by Andreasen et al. was used to classify TDIs. Obesity was defined according to the international cut-off points of body mass index for boys and girls between 2 and 20 years old. RESULTS: The prevalence of TDIs was 16.3%. Enamel fracture was the most common type of TDIs (65%). Neither parents' education level nor family income had a significant effect on TDI occurrence (P > 0.05). Results of multiple logistic regression showed that TDIs were significantly more prevalent among males (OR = 1.42, CI; 1.01-2.01, P < 0.05), and children with inadequate lip coverage (OR = 1.95, CI; 1.35-2.81, P < 0.05). The relationship between TDIs and obesity was not statistically significant (P > 0.05). CONCLUSIONS: Being a male with inadequate lip coverage was associated with higher probability of having a TDI. Obesity had no significant effect on the occurrence of TDIs.