Evaluation of mandibular lingula and foramen location using 3-dimensional mandible models reconstructed by cone-beam computed tomography.

BACKGROUND: The positions of the mandibular lingula and foramen have been set as indexes for inferior alveolar nerve (IAN) block and ramus osteotomies in orthognathic surgery. This study aimed to evaluate the anatomical structures of mandibular ramus, especially the mandibular lingula and foramen, by analyzing the cone-beam computed tomography (CBCT) data of young adults. METHODS: We evaluated 121 sides of hemi-mandibular CBCT model of 106 patients (51 male and 55 female patients; 18 to 36 years old). All the measurements were performed using the 2- and 3-dimensional rulers of OnDemand3D® software. RESULTS: Statistical analysis of the data revealed that there was no significant difference in the mandibular angle between the genders. The mandibular lingula was found to be located at the center of ramus in males, but a little posterior in relation to the center in females. The mandibular lingula was rarely located below the occlusal plane; however, the position of the mandibular foramen was more variable (84.3% below, 12.4% above, and 3.3% at the level of the occlusal plane). CONCLUSIONS: The results of this study provide a valuable guideline for IAN block anesthesia and orthognathic surgery. CBCT can be considered effective and accurate in evaluating the fine structures of the mandible.

Engineered mussel bioglue as a functional osteoinductive binder for grafting of bone substitute particles to accelerate in vivo bone regeneration.

Xenograft bone substitutes, such as deproteinized bovine bone mineral (DBBM), have been widely employed as osteoconductive structural materials for bone tissue engineering. However, the loss of xenograft bone substitute particles in defects has been a major limitation, along with a lack of osteoinductive function. Mussel adhesive protein (MAP), a remarkable and powerful adhesive biomaterial in nature, can attach to various substrates, even in wet environments. Its adhesive and water-resistant abilities are considered to be mainly derived from the reduced catechol form, 3,4-dihydroxyphenylalanine (DOPA), of its tyrosine residues. Here, we evaluated the use of DOPA-containing MAP as a functional binder biomaterial to effectively retain DBBM particles at the defect site during in vivo bone regeneration. We observed that DOPA-containing MAP was able to bind DBBM particles easily to make an aggregate, and grafted DBBM particles were not lost in a defect in the rat calvaria during the healing period. Importantly, grafting of a DOPA-containing MAP-bound DBBM aggregate resulted in remarkably accelerated in vivo bone regeneration and even bone remodeling. Interestingly, we found that the DOPA residues in the modified MAP had an osteoinductive ability based on clear observation of the in vivo maturation of new bones with a similar bone density to the normal bone and of the in vitro osteogenic differentiation of osteoblast cells. Collectively, DOPA-containing MAP is a promising functional binder biomaterial for xenograft bone substitute-assisted bone regeneration with enhanced osteoconductivity and acquired osteoinductivity. This mussel glue could also be successfully utilized as a potential biomaterial for general bone tissue engineering.

In vivo measurements of human gingival translucency parameters.

The aim of this study was to evaluate the relationship between gingival translucency and peri-implant mucosa. A total of 22 peri-implant sites in 16 patients who required tooth replacement in the esthetic zone were included. Color measurements were obtained using a spectrophotometer and customized colored abutments. Mucosal thickness measurements were taken incrementally 0.5 mm from the facial gingival margin on sectioned casts. A statistically significant difference in gingival translucency was observed beginning at 1.5 mm. A negative correlation was observed between the thickness and translucency parameter (TP) (r = -0.64), with TP values decreasing as the gingival thickness increased. The gingival translucency was correlated with the thickness of the peri-implant mucosa and distance from the facial gingival margin.

The clinical and histologic efficacy of xenograft granules for maxillary sinus floor augmentation.

The objective of this study was to investigate the potential of xenograft (cancellous bovine bone) granules to form vital bone in non-natural bone-forming areas of maxillary sinuses. Fourteen sinus augmentations were performed in 14 patients. Surgical outcomes were uneventful, and sufficient radiopaque volume was present radiographically to place dental implants in all sites. Clinical reentry at 6 months revealed bone formation at the osteotomy site. Histologic evaluation of the obtained bone cores revealed that xenograft granules were integrated and surrounded by woven bone and lamellar bone that were in close contact with the particles. The average percentage of newly formed bone at 6 months was 27.5% ± 8.9%. Vital bone formation using the xenograft granules was supported by both clinical and histologic evidence.

Comparison of initial stability parameters and histomorphometric analysis of implants inserted into extraction sockets: human fresh cadaver study.

PURPOSE: To evaluate the initial stability parameters (insertion torque value [ITV], implant stability quotient [ISQ], and Periotest value [PTV]) of implants inserted just after tooth extraction in human fresh cadavers and to examine the relationship between initial stability parameters and bone-to-implant contact ratio (BICR). MATERIALS AND METHODS: This study was undertaken in three fresh human cadavers, which were divided into six groups. A total of 48 sites (four maxillary sites and four mandibular sites in each of the six groups) were selected for the experiment. Extractions were performed under minimal surgical trauma and each manufacturer's recommended formal surgical procedure was followed to place implants. Initial stability parameters (ITV, ISQ via two different instruments, PTV) were measured. Specimens were prepared to analyze histologic findings and BICR. RESULTS: A total of 44 implants were included in this study. Statistically significant correlations were found between ITV and ISQ1 (r = 0.555, P < .001), ITV and ISQ2 (r = 0.398, P < .007), ITV and PTV (r = -0.452, P < .002), ISQ1 and ISQ2 (r = 0.603, P < .001), ISQ1 and PTV (r = -0.576, P < .001), and ISQ2 and PTV (r = -0.423, P < .004). No statically significant correlations were found between BICR and the initial stability parameters. CONCLUSION: The initial stability parameters have statistically significant correlations to each other. However, the initial stability parameters do not seem to present a reliable parameter to predict the area of bone-to-implant contact.

Clinical review of factors leading to perioperative dissatisfaction related to orthognathic surgery.

PURPOSE: The purpose of the study was to obtain information on factors leading to perioperative dissatisfaction of patients who undergo orthognathic surgery for dentofacial deformities. MATERIALS AND METHODS: A total of 44 patients who underwent orthognathic surgery between January 1, 2003, and September 30, 2005, were included in this study. All patients completed 21-item questionnaires, which were analyzed using the frequency distribution and the chi(2) test. RESULTS: The patients lost 6.4% of their body weight after 1-jaw surgery and 6.7% after 2-jaw surgery. The patients returned to their everyday life 4.8 weeks after 1-jaw surgery and 5.2 weeks after 2-jaw surgery. Restoration of sensory function after jaw surgery required almost 10 weeks. CONCLUSION: Written information about possible sequelae and the recovery period and patients' consent to the surgical procedure may be helpful in proper communication, which may reduce patients' perioperative dissatisfaction.

Correlation between bone quality evaluated by cone-beam computerized tomography and implant primary stability.

PURPOSE: To examine the relationship between bone quality, as evaluated by cone-beam computerized tomography (CBCT), and implant primary stability, as measured by resonance frequency analysis (RFA). MATERIALS AND METHODS: A preliminary clinical study was conducted in which implant placements were scheduled for 20 patients. The CT scan was obtained after initial drilling, and implant stability was measured with the Osstell Mentor instrument before flap closure. With CBCT, CT numbers of surrounding bone were calculated and the thickness of compact bone was measured at the buccal, lingual, mesial, and distal surfaces of each implant. The correlations between CT numbers and implant stability quotients (ISQs) and between compact bone thickness and ISQs were tested with the Pearson correlation coefficient. RESULTS: Overall, 61 implants were examined in 20 patients. The statistics showed that the CT numbers and the thickness of compact bone had strong correlations to ISQs (P < .025). CONCLUSION: CT scanning was suggested to be effective for evaluating bone quality and predicting initial implant stability.