Review of Allogeneic Dentin Graft for Maxillofacial Bone Defects.

Although autogenous demineralized dentin matrix (auto-DDM) has shown promising clinical and histological results, it has certain limitations beyond its osteoinductivity and osteoconductivity. Therefore, the application of dentin graft material from other individuals-allogeneic DDM (allo-DDM)-has been considered an alternative to auto-DDM. However, few studies have investigated the osteoinductivity and antigenicity of allo-DDM. Herein, we reviewed all human studies related to allogeneic dentin application for the management of maxillofacial bone defects. Clinical studies have shown the osteoinductivity of allo-DDM in extraskeletal and skeletal sites, regardless of occasional antigenicity. Impact statement Although autogenous demineralized dentin matrix (auto-DDM) has shown promising clinical and histological results, it has certain limitations beyond its proven osteoinductivity and osteoconductivity. Therefore, the application of dentin graft material from other individuals-allogeneic DDM (allo-DDM)-has been considered as an alternative to auto-DDM. However, few studies have investigated the osteoinductivity and antigenicity of allo-DDM. This is the first review of all human studies related to allogeneic dentin grafts for the management of maxillofacial bone defects. Clinical studies have shown the osteoinductivity of allo-DDM in extraskeletal and skeletal sites, regardless of occasional antigenicity.

Influence of General and Local Anesthesia on Postoperative Pain after Impacted Third Molar Surgery.

This study examined the effects of general anesthesia on the postoperative pain level after third molar extractions compared to local anesthesia. This retrospective study included patients who underwent four simultaneous third molar extractions under general or local anesthesia and had records of their postoperative pain levels (visual analog scale, VAS). The pain level was determined in the early (Postoperative day; POD < #3) and late (POD #3-7) periods. The operation time and recently modified difficulty index were analyzed to validate the homogenous condition of the extraction. Of the 227 male inpatients (aged 20.9 ± 1.3 years), 172 and 55 patients underwent third molar extractions under local and general anesthesia, respectively. The age and difficulty index were distributed equally, but the operation time was longer in general anesthesia than in local anesthesia (p < 0.001). The early and late periods featured similar pain outcomes. The operation time correlated with the total periods with a correlation coefficient of 0.271 (p < 0.001). In conclusion, the postoperative pain following whole third molar extraction was related to the operation time rather than the anesthetic methods.

Allogeneic Dentin Graft: A Review on Its Osteoinductivity and Antigenicity.

Studies on allogeneic demineralized dentin matrix (Allo-DDM) implantation in the 1960s and 1970s provided the most reliable preclinical evidence of bone formation and antigenicity in an extraosseous site. Recently, applications of Allo-DDM at skeletal sites were studied, and have provided reliable evidence of bone-forming capacity and negligible antigenicity. However, the osteoinductivity and antigenicity properties of Allo-DDM in extraskeletal sites have not yet been investigated due to the lack of follow-up studies after the initial research. The clinical applications of autogenous DDM (Auto-DDM) have been standardized in some countries. Long-term clinical studies have reported the development of several shapes of Auto-DDM, such as powders, blocks, moldable forms, and composites, with recombinant human bone morphogenetic protein-2. For the development of Allo-DDM as a reliable bone graft substitute next to Auto-DDM, we reviewed preclinical studies on the bone induction capacity of allogeneic dentin at extraskeletal as well as skeletal sites. Electronic databases were screened for this review in January 2020 and searched from 1960 to 2019. This review aims to provide a foundation on the preclinical studies of Allo-DDM, which could enable future researches on its osteogenic capability and antigenicity. In conclusion, Allo-DDM showed great potential for osteoinductivity in extraskeletal sites with low antigenicity, which neither adversely affected osteogenic capability nor provoked immunologic reactions. However, the risk of viral disease transmission should be researched before the clinical application of Allo-DDM.

Classification of postoperative edema based on the anatomic division with mandibular third molar extraction.

PURPOSE: Several investigations have been performed for a postoperative edema after extraction, but the results have been controversial due to low objectivity or poorly reproducible assessments of the edema. The aim of this study was to suggest a classification and patterns of postoperative edema according to the anatomical division associated with extraction of mandibular third molar as a qualitative evaluation method. METHODS: This study was conducted forty-four mandibular third molars extracted and MRI was taken within 48 h after extraction. The postoperative edema space was classified by MRI (one anatomic component-buccinator muscle-and four fascial spaces-supra-periosteum space, buccal space, parapharyngeal space, and lingual space), and evaluated independently by two examiners. The inter-examiner reliability was calculated using Kappa statistics. RESULTS: The evaluation of buccinator muscle edema showed good agreement and the fascial spaces showed constant high agreement. The incidence of postoperative edema was high in the following order: supra-periosteum space (75.00%), buccinator muscle (68.18%), parapharyngeal space (54.55%), buccal space (40.91%), and lingual space (25.00%). CONCLUSION: Postoperative edema could be assessed clearly by each space, which showed a different tendency between the anatomic and fascial spaces.

Effectiveness of Bone Graft for an Alveolar Defect on Adjacent Second Molar After Impacted Mandibular Third Molar Extraction.

PURPOSE: This retrospective study examined distal bone healing on the adjacent second molar between the demineralized bone matrix incorporated with recombinant human bone morphogenetic protein-2 (DBM/rhBMP-2) and a collagen sponge in the mandibular third molar extraction socket. MATERIALS AND METHODS: From 2018 to 2020, 26 extraction patients (male, average 21.5 years), who received a graft (each of 13 using DBM/rhBMP-2 and collagen plug, respectively) on the extraction socket without primary closure, were enrolled in this study. The bony defect was measured by computed tomography before and 6 months after the extraction. The difference in the bone healing was analyzed between the DBM/rhBMP-2 and collagen plug groups using a Mann-Whitney U test. RESULTS: No complications, such as infection and food packing, were encountered. The DBM/rhBMP-2 and collagen plug groups showed a similar distribution of preoperative bony defect (median 5.8 and 5.0 mm, respectively). After 6 months, more bone healing was observed in the DBM/rhBMP-2 group than in the collagen plug group (median 3.85 and 2.37 mm, respectively, P = .029) CONCLUSIONS: A DBM/rhBMP-2 graft after a third molar extraction does significantly alter the bony defect on the distal aspect of the second molar compared with a collagen plug.

Development and validation of a difficulty index for mandibular third molars with extraction time.

OBJECTIVES: : This study aimed to validate the effectiveness of a recently proposed difficulty index for removal of impacted mandibular third molars based on extraction time and suggest a modified difficulty index including the presence of pathologic conditions associated with third molars. MATERIALS AND METHODS: This retrospective study enrolled 65 male patients younger than 25 years with third molars. Extraction time was calculated from start of the incision to the last suture. The difficulty scores for third molars were based on spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points) using cone-beam computed tomography. The difficulty index was defined as follows: I (3-4 points), II (5-7 points), III (8-10 points), and IV (11-12 points). The modified difficulty score was calculated by adding one point to the difficulty score if the third molar was associated with a pathologic condition. Two modified difficulty indices, based on the presence of pathologic conditions, were as follows: the half-level up difficulty index (HDI) and the one-level up difficulty index (ODI) from the recently proposed difficulty index. RESULTS: The correlations between extraction time and difficulty index and or modified difficulty indices were significant (P<0.001). The correlation coefficient between extraction time and difficulty index was 0.584. The correlation coefficients between extraction time and HDI and ODI were 0.728 and 0.764, respectively. CONCLUSION: Extraction time of impacted third molars exhibited a moderate correlation with difficulty index and was strongly correlated with the modified indices. Considering the clinical implications, the difficulty index of surgical extraction should take into consideration the pathologic conditions associated with third molars.

Protrusive maxillomandibular fixation for intracapsular condylar fracture: a report of two cases.

Clinical limitations following closed reduction of an intracapsular condylar fracture include a decrease in maximum mouth opening, reduced range of mandibular movements such as protrusion/lateral excursion, and reduced occlusal stability. Anteromedial and inferior displacement of the medial condyle fragment by traction of the lateral pterygoid muscle can induce bone overgrowth due to distraction osteogenesis between the medial and lateral condylar fragments, causing structural changes in the condyle. In addition, when conventional maxillomandibular fixation (MMF) is performed, persistent interdental contact sustains masticatory muscle hyperactivity, leading to a decreased vertical dimension and premature contact of the posterior teeth. To resolve the functional problems of conventional closed reduction, we designed a novel method for closed reduction through protrusive MMF for two weeks. Two patients diagnosed with intracapsular condylar fracture had favorable occlusion after protrusive MMF without premature contact of the posterior teeth. This particular method has two main advantages. First, in the protrusive position, the lateral condylar fragment is moved in the anterior-inferior direction closer to the medial fragment, minimizing bone formation between the two fragments and preventing structural changes. Second, in the protrusive position, posterior disclusion occurs, preventing masticatory muscle hyperactivity and the subsequent gradual decrease in ramus height.

Recording natural head position using an accelerometer and reconstruction from computed tomographic images.

OBJECTIVES: The concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position "when a man is standing and his visual axis is horizontal." NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer. MATERIALS AND METHODS: A total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements. RESULTS: The average difference in the angles between the clinical photograph and the 3D model was 0.04° for roll and 0.29° for pitch. The paired ttests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05). CONCLUSION: By overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.