It can be inferred that there is a wide anatomical variation in the prevalence, size, location, and morphology of maxillary sinus septa, irrespective of the degree of atrophy. Therefore, to prevent the likelihood of complications arising during sinus augmentation procedures, a thorough and extensive understanding of the anatomic structures inherent to the maxillary sinus is indispensable.

Objectives:To test whether or not alveolar ridge preservation reduces vertical changes in the posterior maxilla compared to spontaneous healing following tooth extraction. Materials and methods:Forty subjects requiring extraction of maxillary posterior teeth with root apices protruding into the maxillary sinus floor were consecutively enrolled. Patients were randomly assigned to either one of two surgical interventions: an alveolar ridge preservation procedure using collagenated bovine bone mineral and a resorbable collagen membrane (test) or no grafting (control). Cone-beam computed tomographies were taken immediately and at 6 months after surgery, prior to dental implant placement.Results: Based on radiographic data, the level of the sinus floor remained stable over time (baseline to 6 months) in the test group (−0.14 mm [−0.31, −0.02]). In the control group, the sinus floor level shifted more coronally (−1.16 mm [−1.73, −0.61]) than the test group (p < 0.05). The test group demonstrated a significantly larger residual bone height than the control group at 6 months (7.30 mm [6.36, 8.20] vs. 4.83 mm [3.94, 5.76], respectively, p < 0.05). Implant placement without any additional sinus augmentation procedure was performed in 42.9% of test group cases, whereas in all of the subjects in the control group an additional augmentation procedure was needed (100% of the cases).Conclusion: Alveolar ridge preservation in the posterior maxilla maintained the vertical bone height more efficiently and resulted in less need for sinus augmentation procedures at 6 months compared to spontaneous healing. K E Y W O R D Salveolar ridge preservation, cone-beam CT, maxillary sinus, pneumatization, sinus augmentation, superimposition, vertical dimension

The palatal masticatory mucosa thickness increased from the canine to premolar region but decreased at the first molar region and increased again in the second molar region, with the thinnest area at the first molar region and the thickest at the second premolar region. The canine to premolar region seems to be the most appropriate donor site that contains a uniformly thick mucosa. CT can be considered an alternative method for the measurement of palatal soft tissue thickness.

PurposeThis study evaluated the spontaneous healing capacity of surgically produced cranial defects in rabbits with different healing periods in order to determine the critical size defect (CSD) of the rabbit cranium.MethodsThirty-two New Zealand white rabbits were used in this study. Defects of three sizes (6, 8, and 11 mm) were created in each of 16 randomly selected rabbits, and 15-mm defects were created individually in another 16 rabbits. The defects were analyzed using radiography, histologic analysis, and histometric analysis after the animal was sacrificed at 2, 4, 8, or 12 weeks postoperatively. Four samples were analyzed for each size of defect and each healing period.ResultsThe radiographic findings indicated that defect filling gradually increased over time and that smaller defects were covered with a greater amount of radiopaque substance. Bony islands were observed at 8 weeks at the center of the defect in both histologic sections and radiographs. Histometrical values show that it was impossible to determine the precise CSD of the rabbit cranium. However, the innate healing capacity that originates from the defect margin was found to be constant regardless of the defect size.ConclusionsThe results obtained for the spontaneous healing capacity of rabbit cranial defects over time and the underlying factors may provide useful guidelines for the development of a rabbit cranial model for in vivo investigations of new bone materials.

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rhGDF-5/beta-TCP has a greater potential to support the regeneration of the periodontal attachment. Long-term studies are necessary to confirm the uneventful maturation of the regenerated tissues.

Various synthetic bone substitutes have been developed to reconstruct the bony defects that clinicians often encounter during surgical procedures. Among various synthetic bone substitutes, calcium phosphate (Ca-P) ceramics have been investigated because their composition and structure are similar to those of human bone. We evaluated the bone healing and biodegradation patterns of three types of Ca-P ceramic particle with various hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) weight ratio: pure β-TCP, biphasic Ca-P (BCP) with a HA/β-TCP weight ratio of 60/40 (BCP 60/40), and BCP with an HA/β-TCP weight ratio of 20/80 (BCP 20/80). Four 8-mm-diameter defects were created in ten rabbits. Three of the defects in each rabbit were separately and randomly filled with one of the three experimental Ca-P ceramic particles, and the fourth was filled with blood clots (control). The specimens were harvested at 2 and 8 weeks post-surgery. The histologic and histometric findings revealed that the augmented space and new bone formation were significantly better for all three Ca-P ceramics than for the control group at both 2 and 8 weeks (p < 0.05). Compared to the pure β-TCP, the two BCP groups were found to provide a larger amount of newly formed bone and bone density at the 2- and 8-week post-operative periods (p < 0.05). Throughout the observation period, BCP 60/40 and BCP 20/80 exhibited a similar bone healing and biodegradation patterns with regard to both individual particles and the total augmented area in vivo.

In conclusion, ErhBMP-2-loaded ACS showed enhanced osteoinductive potential, particularly with regard to bone closure of a sinus window and facilitated maturation of the newly formed bone within the rabbit sinus cavity. However, the structural durability of ACS was not sufficient to maintain the augmented volume in the sinus.