BMC Oral Health最新文献

Background: Computer-Aided Design (CAD) combined with 3-dimensional (3D) printing technology has been extensively applied in the treatment of endodontic diseases. The goal of this novel report is to highlight a fully guided autotransplantation with CAD and 3D printing technology for treatment of tooth fracture.

Case presentation: The maxillary left first molar #26 had a vertical fracture that severely affected occlusion and life quality of the patient. Clinical examination showed an oblique crack across the mesiobuccal cusp and the distopalatal cusp of #26, cone-beam computed tomography (CBCT) showed a vertical fracture line reaching the floor of pulp chamber, a subtle increase in the palatal periodontal ligament space, and hypodensity in the distobuccal apex area. Due to the strong desire to preserve natural tooth and financial considerations, the patient declined conventional prosthetic restoration and chose autotransplantation of mandibular left third molar #38 to the site of #26. A 3D printed guide was used to precisely prepare the extraction socket, facilitating the immediate and accurate autotransplantation of #38 into the site of #26. Root canal therapy was performed 3 weeks after surgery.

Results: During the 3-year follow-up, the patient could chew normally without any discomfortable feelings, X-ray radiographs showed a significant increase in bone density around the root and a superior periodontal ligament healing without root resorption.

Conclusions: For patients who do not choose prosthetic restoration due to socio-economic conditions, we propose tooth autotransplantation as an alternative treatment for tooth fractures under the help of modern CAD and 3D printing technology.

Background Diagnosing pulp status in primary molars is often challenging when clinical and radiographic findings fall into an equivocal range between reversible and irreversible pulpitis. This uncertainty complicates treatment decisions between pulpotomy and pulpectomy. This study aimed to compare long-term survival outcomes of pulpotomy and pulpectomy in primary molars with diagnostically equivocal pulp status and to identify potential predictors of treatment success.MethodsA retrospective cohort study was conducted on 312 primary molars from children aged 3-8 years treated at Hefei Stomatological Hospital. All teeth exhibited borderline pulp status, such as prolonged bleeding (5-10 min) or inconclusive radiographic signs. Teeth were treated with pulpotomy using iRoot(Innovative BioCeramix Inc.,Vancouver, Canada) BP Plus or pulpectomy with ZOE-iodoform paste, followed by stainless steel crown restoration. Propensity score matching (1:1) was applied to balance baseline variables. Kaplan-Meier analysis and Cox proportional hazards models were used to evaluate survival outcomes and predictors of failure.ResultsAfter matching, 156 pairs were analyzed. The 24-month survival rate was significantly higher in the pulpotomy group (86.4%, 95% CI: 81.2-91.6%) compared to the pulpectomy group (67.1%, 95% CI: 60.3-73.9%) (P < 0.001). In asymptomatic teeth, pulpotomy was associated with a significantly lower risk of failure (HR = 0.42, P = 0.002), while no significant difference was found in symptomatic cases (HR = 0.88, P = 0.41). Internal resorption was more common in the pulpotomy group, whereas external resorption and periapical pathology were more frequent after pulpectomy.ConclusionsIn primary molars with equivocal pulp status, pulpotomy demonstrates superior long-term survival, particularly in asymptomatic cases. These findings support a more conservative approach and suggest revisiting current guidelines for managing diagnostically borderline pulp conditions.

Objectives: This study was to investigate the enamel thickness in different anatomical landmarks of occlusal surfaces of first molars and to evaluate probability of dentin exposure (DE) and percentage of remaining occlusal enamel areas following occlusal veneer preparation at different depths.

Materials and methods: Cone beam computed tomography (CBCT) images of maxillary and mandibular first permanent molars (N = 90, each 45) were used to measure occlusal enamel thickness at specific landmarks. The probability of DE after different preparation depths was calculated. Two freshly-extracted first molars were scanned using a Micro-CT to obtain STLm files. 72 resin models were 3D-printed and randomly assigned to 12 groups (n = 6) before they were prepared for occlusal veneer at 0.6-2.0 mm of depths. The prepared models were scanned to obtain STLp files that were aligned and superimposed to STLm. Prepared occlusal enamel surface areas and dentin exposure areas were analyzed.

Results: Enamel thickness ranged from 0.93 to 1.93 mm in maxillary first molars and 0.98-1.91 mm in mandibular first molars. The central fossa (CF) showed the thinnest enamel in both maxillary and mandibular first molars. After tooth preparation of occlusal veneer of first molar, probability of DE was zero at 0.6 mm, < 20% at 0.8 mm, < 60% at 1.0 mm, around 80% at 1.2 mm, in which the highest probability of DE was CF. Even at 1.2 mm, percentage of occlusal enamel area of first molar was 82.10 ± 1.45% (maxillary) and 94.83 ± 1.66% (mandibular).

Conclusions: For bonding to high percentage (≥ 80%) of occlusal enamel areas of unworn tooth, tooth preparation of occlusal veneers should be not deeper than 1.2 mm, and for bonding to total occlusal enamel area, tooth reduction should be around 0.6 mm.

Clinical relevance: Dentists should carefully consider occlusal enamel thickness distribution for tooth preparation of occlusal veneer because middle-aged and senior people often have tooth wear to some degree.