Canal diameter enlargement was greater anteriorly to the ridge and posteriorly to the palatal bone, mainly because of tooth extraction. The atrophy of disuse may influence surrounding structures, similar to the maxillary sinus tendency to expand into surrounding bone mainly after tooth loss.

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The purpose of this article was to define the anatomic and radiographic courses of the incisive mandibular canal and discuss its clinical significance. The study group comprised of 46 hemimandibles fixed in formalin. After radiographic examination, the buccal cortical plate of the mandible was removed leaving the bony frame of the incisive bundle intact. The morphology of the bony walls of the canal was evaluated, as having complete, partial, or no cortical walls. The course of the intraosseous pathway of the canal and its diameter in four different locations were recorded. An incisive bundle was anatomically found in all hemimandibles, travelling within a canal with complete (n = 10), partial (n = 27), or no (n = 9) bony cortical borders. The diameter of the canal ranged from 0.48 mm to 2.9 mm. Radiographically, the canal was either well defined (n = 11, 24%), poorly defined (n = 15, 32%), or undetectable (n = 20, 44%). A statistically significant correlation was found between the anatomic structure of the incisive canal bony borders and its radiographic detectability (p = 0.043). No correlation was found between the anatomic and radiological width of the incisive canal diameter. An incisive canal with a large diameter could have an important role in successful osteointegration and prevention of postoperative sensory disturbances. According to the present study, the ability to interpret the incisive canal from conventional radiographs is limited. Therefore, it is recommended to use conventional tomographs or computerised tomographic dental scans for better imaging of the intermental foraminal area.

The present study was conducted to histologically and histomorphometrically evaluate the application of cancellous bone-block allografts for the augmentation of the posterior atrophic mandible. Twenty-four consecutive patients underwent augmentation with cancellous bone-block allografts in the posterior mandible. A bony deficiency of at least 3 mm horizontally and/or vertically according to CT para-axial reconstruction served as inclusion criteria. Following 6 months, 85 implants were placed and a cylindrical sample core was collected. All specimens were prepared for histological and histomorphometrical examination. Implant survival rate was 95.3%. Follow-up ranged 12-66 months (mean 43 ± 19 months). The mean newly formed bone was 44 ± 28%, that of the residual cancellous bone-block allograft 29 ± 24%, and of the marrow and connective tissue 27 ± 21%. Statistically significant histomorphometric differences regarding newly formed bone (69% vs. 31%, p = 0.05) were found between younger (< 45 years) and older (> 45 years) patients, respectively. Histomorphometric differences regarding residual cancellous bone-block allograft (17% vs. 35%) and of the marrow and connective tissue (14% vs. 34%) were not statistically significant. Cancellous bone-block allograft is biocompatible and osteoconductive, permitting new bone formation following augmentation of extremely atrophic posterior mandible with a two-stage implant placement procedure. New bone formation was age-dependent.

Failures caused by complications were rarely noted in association with cancellous block grafting. The incidence of complications in the mandible was significantly higher. Soft tissue complications do not necessarily result in total loss of cancellous block allograft.

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Peripheral giant cell granuloma can develop in association with dental implants. Clinically, the lesions are similar to the classical PGCG. In the present study, the precise incidence could not be concluded because of the small number of selected cases. Due to the aggressive nature of the lesion and the high recurrence rate, implants can fail unless the lesion is detected early and proper surgical removal is performed. Tissue removed from the peri-implant area should always be submitted for histologic examination for accurate diagnosis.