Restoration of Severely Damaged Tooth by Zirconia based Endocrown: Case Series.

Following endodontic (root canal) treatment, teeth loss their mechanical properties, and the teeth become fragile because of the removal of pulp and dentin. Hence, prosthetic restoration of root canal-treated teeth is a challenge. Endocrown is a single restoration, and it is considered an excellent alternative restoration for teeth with large coronal destruction and root canal treatment difficulties. Zirconia endocrowns are reliable materials for root canal-treated molars with extensive loss of crown structure. This case series presents four cases of restoration of severely damaged molars presenting various symptoms and prosthetic restorations were done by zirconia-based endocrown. The prognosis in all patients was good.

Validation of a new experimental model of extrusive luxation on maxillary molars of rats: a histological study.

BACKGROUND/AIM: The aim of this study was to test and validate a new model of extrusive luxation trauma on maxillary first molars of rats. MATERIAL AND METHODS: Forty adult male rats (Rattus norvegicus albinus, Wistar; weight = 230-250 g), 45 days old, were divided into eight groups (n = 5): control groups, in which animals were not subjected to any procedure and waited 1 day (GC1D) or 3 days (GC3D) for euthanasia, and experimental groups, in which animals were subjected to forces of 1100cN, 1300cN, or 1500cN and waited 1 or 3 days for euthanasia (GT1100/1D, GT1100/3D, GT1300/1D, GT1300/3D, GT1500/1D, GT1500/3D). In animals of the experimental groups, trauma was produced by an extrusive force in maxillary first right molars. Four-micrometer serial cuts stained with hematoxylin and eosin (HE) were made. Descriptive microscopic analysis of first upper right molar and semi-quantitative analysis (scores 1 to 4) of intensity of acute and chronic inflammation and vascular changes in the periodontal ligament and active and inactive external root resorption were conducted. The distribution of scores in the groups was compared using the Freeman-Halton extension of Fisher's exact test. The significance level was 5%. RESULTS: It was observed that vascular disorders (bleeding) on the periodontal ligament became more evident with increasing extrusive force. CONCLUSIONS: This new method was capable of generating histological changes, proving its secure application in this research area. The 1500cN force produced more damage on the periodontal ligament. CLINICAL RELEVANCE: The validation of a new experimental method can produce more reliable evidence in further research.

Duration from Initial Symptoms to Diagnosis of Vertical Root Fracture in Dental Offices.

Diagnosing vertical root fracture (VRF) is difficult. Here, we retrospectively investigated the duration from initial symptoms to a definite diagnosis of VRF in dental offices. Data were collected on patients with VRF between July 2013 and June 2015. Initial symptoms were ascertained from clinical records. The focus was on the maxillary second premolars and mesial roots of the mandibular first molars, where VRF is most frequent. All VRF in the bilateral dentition was analyzed. Only cases in which the buccal-lingual plane of the root was fractured were included. Data from 31 dental offices revealed a total of 39 VRFs in the maxillary second premolars and 43 in the mandibular mesial roots of the first molars. The patients comprised 42 males and 40 females, and the average age was 59.7±11.6 years at initial onset of symptoms. The mean duration from initial symptoms to a definite diagnosis in the maxillary second premolars was 18.3±22.5 months, while that in the mandibular first molars was 16.1±17.8 months. The cumulative diagnostic rate was 48.7% at 12 months and 79.5% at 24 months in the maxillary second premolars, and 38.1% at 12 months and 86.0% at 24 months in the mandibular first molars. No significant difference was observed between tooth type. If VRF is suspected, doctors should explain the risks of tooth extraction and begin considering treatment options. The present results revealed that 80% of VRFs were diagnosed within 2 years of initial onset of symptoms.

Replacing Heavily Damaged Teeth by Third Molar Autotransplantation With the Use of Cone-Beam Computed Tomography and Rapid Prototyping.

This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome.

Horizontal root fractures in posterior teeth without dental trauma: tooth/root distribution and clinical characteristics.

AIM: To describe the clinical characteristics and radiographic findings of horizontal root fractures (HRF) in posterior teeth without a history of dental trauma. METHODOLOGY: A total 24 patients and 31 HRF cases in 28 posterior teeth were collected from 2006 to 2015. Clinical examinations and radiographic imaging were evaluated. Value of confidence intervals of the proportions was calculated for data presentation. RESULTS: The number of males (54%) was similar to females (46%). The patients were predominantly between 50 and 70 years of age (75%). Most HRF cases were found in nonendodontically treated teeth (79%), without crown and bridge restorations (82%), and maxillary molars (54%). Many roots of maxillary molars had developed HRF, and the probability was nearly equal. Fractured teeth usually presented with periodontal and apical bone loss, and most patients (92%) were diagnosed with full mouth chronic periodontitis. Tooth wear was another common clinical feature amongst these patients. CONCLUSIONS: HRF in posterior teeth without dental trauma occurred mainly in patients aged between 50 and 70, in nonendodontically treated teeth, teeth with attrition but without crown and bridge restorations, maxillary molars and with periodontal and periapical bony destruction. Periodontal condition, occlusal wear and patients' age at diagnosis were the possible related factors. HRF in posterior teeth without dental trauma is a diagnostic challenge and even misdiagnosed. A thorough clinical examination, radiographic analysis and recognition of the clinical characteristics are helpful in the early diagnosis and treatment of HRF.

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.

Removal of Long-Term Broken Roots Displaced Into the Maxillary Sinus by Endoscopic Assistant.

PURPOSE: This report presented a patient with 2 long-term broken roots displaced in left maxillary sinus. The residual root fragments made the patient uncomfortable in both mind and body and interfered with prosthodontics work. The application of endoscope combined with piezoelectric device both helps in removing the broken roots successfully with minimally surgical injury and preserves the residual alveolar bone. METHODS: Computed tomography scans and 3-dimensional reconstructions located the broken roots. A 1.0 cm × 1.5  cm rectangle bone window on anterolateral sinus wall was opened by a piezoelectric device to place the endoscope and forcep into sinus. Two broken roots could be observed clearly via a endoscopic screen. They were removed by a mini goblet forcep completely and efficiently. A whole bone lid was replaced with a biological membrane to help repair bone defect after removing procedure. RESULTS: The operation is about 20 minutes with endoscope and piezoelectric device helped to save a lot of time and provided excellent visual surgical field. Main postoperative adverse effects were swelling, numbness, and temporal no-vitality for the first premolar (24). Three months later, computed tomography shows the Schneiderian membrane thinned to around 0.8  mm. The bone lid is on its position and starts to perform synostosis. The 24 tooth is still dysesthetic and needs time to recover. CONCLUSIONS: Endoscopic surgery combined with a piezoelectric device has obvious advantage of minimizing surgical injury and providing excellent visibility of surgical field when removing long-term foreign bodies in maxillary sinus. It is efficient and protects the residual alveolar bone.

Effects of cyclic loading and toothbrush abrasion on cervical lesion formation.

This study sought to determine the effect of cyclic loading and toothbrush abrasion (with and without abrasive slurries) on cervical lesion formation. The roots of extracted human third molars were embedded in acrylic resin, leaving 2 mm of root structure and crowns exposed. Teeth were divided into 6 groups (n = 10) with the following treatments: no treatment (control), cyclic load in distilled water, brushing with distilled water, cyclic load followed by brushing with distilled water, brushing with toothpaste slurry, and cyclic load followed by brushing with toothpaste slurry. Cyclic loading and toothbrushing machines subjected the teeth to 1.6 million cyclic loads and 30,000 brushing strokes, the equivalent of 4 years of function and brushing for an average patient. The teeth were scanned with a 3-dimensional optical profilometer to determine the volumetric loss of tooth structure. Load cycling had no significant effect on cervical tooth loss. Brushing with toothpaste resulted in significantly greater cervical tooth loss than brushing with water, which in turn was significantly greater than no treatment at all.

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.

Hemisection: A Treatment Option for an Endodontically treated Molar with Vertical Root Fracture.

Vertical root fractures (VRF) in endodontically treated teeth have long been reported and pose diagnostic difficulties. A hemisection/root resection procedures removes the fractured fragments completely, and retains a portion of the compromized tooth offers a predictable treatment option. The key to this rests in ideal case selection involving balancing all indications and contraindications. The success of the treatment depends on careful case selection based on a firm set of guidelines. This article presents a case with VRF in an endodontic treated molar. This article describes the case of a 65-year-old man with a VRF on the mesial root and a healthy periodontium supporting the distal root making it ideal for retention as well as restoration and support of the final prosthesis. Also, the patient was motivated to try and save as much of the tooth as possible. Postoperatively no untoward complication was reported making it an alternative treatment option in patients with VRF in a molar, willing to retain the remaining tooth portion. With all other factors balanced, it allows for retaining the remaining intact portion of the tooth structure.

The application of indirect composite onlays in the restoration of severely broken down posterior teeth.

Increasing interest has developed among dentists regarding alternatives to traditional full-coverage crowns for the restoration of extensively broken-down teeth that are both aesthetic and less destructive of remaining tooth structure. Indirectly fabricated resin composite onlays may offer a viable and cost-effective treatment option in such cases. This paper describes the clinical rationale for resin-based onlays, and includes a case report illustrating the author's experience with the technique to date.

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.

A qualitative investigation of RANKL, RANK and OPG in a rat model of transient ankylosis.

INTRODUCTION: Previous studies have found ankylosis occurs as a part of the inflammatory process of aseptic root resorption initiated in a rat model. The physiologic mechanisms behind the development of dentoalveolar ankylosis and healing response are still unclear. While receptor activator of nuclear factor-κß ligand (RANKL), receptor activator of nuclear factor-κß (RANK) and osteoprotegerin (OPG) have gained momentum in the understanding of resorption, no study to date has investigated their role in dentoalveolar ankylosis. AIMS: The aims of this study were to investigate if, and when, ankylosis occurred in the rat PDL, whether the resolution of ankylosis occurred with time and, finally, to observe the expression of RANKL, RANK and OPG during the ankylotic process. MATERIALS AND METHODS: Dry ice was applied for 20 minutes to the upper right first molar crown of 15 eight-week-old, male Sprague-Dawley rats. An additional three rats served as untreated external controls. Groups of three rats were sacrificed after the thermal insult on day 0, 4, 7, 14 and 28 respectively. Each maxilla was dissected out and processed for histological examination and RANKL, OPG and RANK immunohistochemistry. RESULTS: By the use of light microscopy and H&E staining, no ankylosis was detected in the external control group and the experimental groups at days 0 and 4. On day 7, disruption within the periodontal ligament was observed in the interradicular region and the initial signs of ankylosis were seen in the form of finger-like projections extending from the alveolar bone towards the cementum. Fourteen days after the thermal insult, all animals exhibited extensive ankylosis that spanned the entire interradicular periodontal space. At 28 days, the development of ankylosis appeared to have ceased and repair was observed, together with an intact periodontal ligament in all but one rat. Positive staining results were obtained with RANKL, RANK and OPG antibodies. The expressions of RANKL, RANK and OPG were similar in the external control group, 0-, 4-, and 28-day experimental groups. In the 7- and 14-day experimental groups, RANKL, RANK and OPG were expressed in the blood vessels within the ankylotic regions. CONCLUSIONS: During the development of ankylosis and its resolution, it was concluded from their simultaneous presence that there is a complex interaction between RANKL, RANK and OPG that requires further investigation.

Dental management of florid cemento-osseous dysplosia.

Cemento-osseous dysplasia encompasses several different clinical and radiographic presentations, including periapical, focal and florid cemento-osseous dysplasia (FCOD). FCOD is usually asymptomatic and discovered only fortuitously. No treatment is required unless the lesion is secondarily infected. Oral hygiene advice should be emphasized for patients with FCOD to prevent caries and periodontal diseases and to maintain natural teeth. Osseointegration of implants would likely not be successful in these patients because the bone is abnormal and not well-vascularized.

Isolated fracture of the coronoid process following a molar extraction: A rare case report.

Isolated coronoid process fractures are uncommon, and iatrogenic isolated fractures are extremely rare. This case describes a displaced fracture of an isolated coronoid process thought to be due to excessive force applied by a dentist that had been overlooked and left untreated for about a month. The patient was a woman in her late 50's and she had undergone a molar extraction. Her dentist had confused her symptoms of trismus, pain, and facial oedema with the complex tooth extraction procedure. Following a cone-beam computed tomography (CBCT) scan we showed that the mandibular coronoid process on her right side had suffered a longitudinal fracture, and the fractured fragment had rotated upwards and inwards. Following successful surgical elimination of the fragmented coronoid process, the patient received targeted physiotherapy sessions that yielded excellent results. At the five-month follow-up, the ability of the patient to open her mouth had improved enormously, and her facial appearance almost recovered to its original state.

Traumatic dental injuries and molar incisor hypomineralization: a cross-sectional study of schoolchildren from southern Brazil.

PURPOSE: To describe the prevalence and the variables associated with TDIs in schoolchildren aged 8 to 14 years in Estância Velha city in southern Brazil, placing emphasis on molar incisor hypomineralization. METHODS: Students enrolled in public schools of a medium-sized city in the southern Brazil were selected using cluster random sampling. Clinical examinations assessed molar incisor hypomineralization-MIH (European Academy of Pediatric Dentistry criteria), dental caries (DMFT index), and TDIs (O'Brien's criteria). Socioeconomic and demographic variables were assessed using a standardized questionnaire. Prevalence ratios were estimated using Poisson regression (p < 0.05). RESULTS: 513 students (54.8% female), with a mean age of 11.6 (± 1.9) years, participated in the study. The prevalence of TDIs was 11.3%, with enamel fracture representing 90.4%. The high prevalence of traumatic dental injuries was associated with MIH (PR: 2.22 CI: 1.27; 3.87; p < 0.01) and overjet > 3 mm (PR: 2.03 CI 1.19; 3.45; p < 0.01). CONCLUSION: The sample of schoolchildren from southern Brazil had a low prevalence of traumatic dental injuries. Molar incisor hypomineralization and increased overjet were associated with the higher prevalence of traumatic dental injuries.

Oral pathologies of the Neolithic Iceman, c.3,300 BC.

The famous Iceman 'Ötzi' (South Tyrol Museum of Archaeology, Bolzano, Italy), a Neolithic human ice mummy, offers a unique opportunity to study evolutionary aspects of oral disease. The aim of this study was to assess, for the very first time, his oral cavity, which surprisingly had never been examined systematically. Based on several computed tomography (CT) scans from 1991 onwards and on macroscopic investigation, only a few findings, such as a central maxillary diastema, heavy abrasions, and missing wisdom teeth, were known. We re-evaluated the latest CT scans from 2005 and found various oral pathologies. In line with the increase of tooth decay in the Neolithic - because of diet change in this historic transition phase - several carious lesions were found, one of which penetrated into the dental pulp. In accordance with the Iceman's troubled life, as several injuries on his body and his violent death attest, mechanical trauma of one of his upper front teeth is evident. Finally, the poor periodontal condition of the Iceman's dentition (e.g. loss of alveolar bone), indicative of periodontitis, was assessed. These oral pathological findings in the Iceman's dentition provide a unique glimpse into the evolutionary history of oral conditions.

Correlation between cuspal inclination and tooth cracked syndrome: a three-dimensional reconstruction measurement and finite element analysis.

BACKGROUND/AIM: This paper explored the correlation between cuspal inclination and tooth cracked syndrome by measuring and reconstructing the cuspal inclinations of cracked maxillary first molars through three-dimensional (3D) finite element analysis (FEA). MATERIAL AND METHODS: The cuspal inclinations of 11 maxillary left first molars with cracked tooth syndrome and 22 intact controls were measured by 3D reconstruction. The mean values of each group were used to construct two 3D finite element models of maxillary first molar for comparing stress distribution under the loads of 200N at 0°, 45°, and 90°, respectively, to the tooth axis. RESULTS: There was statistically significant difference in the cuspal inclination between the incompletely fractured group and the intact control group ( P  < 0.001), which was 5.5-6.7 degrees steeper. The model from the mean cuspal inclinations of the incompletely fractured molars showed the maximum tensile stress of 5.83, 10.87, and 25.32 MPa, respectively, in comparison with 5.40, 8.49, and 22.76 MPa for the model of the control group. Besides, the tensile stress was mainly at the center groove and cervical region of the molar model. CONCLUSIONS: Steeper cuspal inclinations resulted in an increment in tensile stress that was mainly at the center groove and cervical region of the molar model under equivalent loads. Higher unfavorable tensile stress was generated with the increasing horizontal component load on the cuspal incline. This indicates an effective reduction of cuspal inclination to the compromised teeth for dentists.

Bilateral complicated crown fractures secondary to chin injury: a case report.

Traumatic injuries to the chin are not uncommon in children. Nevertheless, crown fractures, which are common sequelae to this type of injury, might be overlooked, especially if dental care is not sought immediately after a visit to a non-dental facility. The present case report reviews the delayed diagnosis and treatment outcome of a bilateral posterior complicated crown fracture affecting mandibular second primary molars in a young child. Pharmacologic and orthodontic considerations are also discussed in the paper.

Sealing ability of mineral trioxide aggregate, calcium phosphate cement, and glass ionomer cement in the repair of furcation perforations.

OBJECTIVES: The purpose of this study was to evaluate the in vitro sealing ability of three repair materials. Mineral trioxide aggregate (MTA; Group A), calcium phosphate cement (CPC; Group B), and light cured glass ionomer cement (GIC; Group C) when used to repair the perforation created in the pulpal floor of fifty extracted human permanent molars. MATERIALS AND METHODS: Preparation of access openings and furcation perforations were done, and the teeth divided into five experimental groups (A, B, C) including two controls (D, E) with ten samples in each group randomly. Following the repair procedure, the pulp chambers and access openings were filled with composite resin and immersed in 2% methylene blue solution for 48 hours. The teeth were sectioned longitudinally and the linear dye penetration measured under a stereomicroscope. RESULTS: The comparison of the linear length of micro-leakage (mm) among the experimental groups revealed no significant difference (p = 0.332). On calculating the percentage of depth of leakage to the total length of the perforation, it was observed that the mean leakage was 35.5% in Group A, 53.6% in Group B and the highest, 87.5% in Group C. The mean of leakage percentage was statistically significant by Kruskal-Wallis test (p = 0.003). The results indicated that the dye penetration used as furcation perforation repair material was least with mineral trioxide aggregate. Comparing the depth of penetration of dye, 50% of the Group A samples showed less than 25% of depth penetration. While 40% of Group B cases had more than 50% dye penetration. In our study, all Group C teeth had > or = 50% dye penetration. CONCLUSIONS: The present study indicated that GIC had the greatest dye penetration followed by CPC and MTA. Mineral trioxide aggregate and calcium phosphate cement had comparatively better sealing ability than glass ionomer cement.