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Selective reduction of bone without collateral damage (nerves, teeth) is essential in apicectomy. To test whether skills acquired on a virtual apicectomy simulator (VOXEL-MAN system with integrated force-feedback) are transferable from virtual to physical reality, two groups of trainees were compared. Group 1 received computer-based virtual surgical training before performing an apicectomy in a pig cadaver model. The probability of preserving vital neighboring structures was improved significantly, i.e. six-fold, after virtual surgical training (P < 0.001). The average volume of the bony defects created by the trainees of Group 2 (mean: 0.47 ml) was significantly (P < 0.001) larger than by the trainees of Group 1 (mean: 0.25 ml). Most importantly, the ability to objectively self-assess performance was significantly improved after virtual training. Training with a virtual apicectomy simulator appears to be effective, and the skills acquired are transferable to physical reality.

This study was designed to compare bone regeneration of tissue-engineered bone from adipose-derived stem cell and autogenous bone graft in a canine maxillary alveolar cleft model. In this prospective clinical trial, mesenchymal stem cells (MSCs) were isolated from subcutaneous canine adipose tissue. Undifferentiated cells were incubated with a 3 mm 3 mm 3 mm hydroxyapatite/beta-tricalcium phosphate scaffold, in specific osteogenic medium for 21 days. Four mongrel dogs were prepared by removal of two of the three incisors bilaterally and a 15 mm defect in bone was created from crest to nasal floor. After healing, repair was followed by a tissue engineered bone graft from adipose- derived stem cells on one side and corticocancellous tibial auto graft on the other side. Bone regeneration was evaluated by histomorphometry on days 15 and 60 after implantation. The data were analysed with descriptive and t test methods (a = 0.05). Bone formation on the autograft sides was higher than on the stem cell sides at 15 and 60 days, 45% and 96% versus 5% and 70%, respectively. Differences between the two groups at 15 and 60 days were significant (p = 0.004 and 0.001, respectively). Although autograft is still the gold standard for bone regeneration, tissue engineered bone may provide an acceptable alternative.

The aim of this investigation was to determine the influence of additional surgical procedures on the root development of transplanted teeth. The study sample consisted of 90 immature third molars transplanted in 88 patients. All transplanted teeth were at root development stages 3 to 4. Free bone autografts were used in 23 cases (bone autograft group), mainly because of vertical atrophy of the alveolar process. A splitting osteotomy of the alveolar process was performed in 25 cases with marked horizontal atrophy (osteotomy group). Forty-two teeth transplanted into a fresh extraction site immediately after extraction of the non-retainable tooth served as controls. At root development stage 3, significant differences were determined between the osteotomy and the control groups in final root length (P0.001) and root length increment (P=0.004). Transplants in the osteotomy group revealed a significantly lower root length increment than transplants in the bone autograft group (P=0.008). No significant intergroup differences were observed at root development stage 4. These results indicate that a splitting osteotomy of the alveolar process has a negative effect on root development of transplanted teeth at earlier developmental stages.

The purpose of this study was to compare the periodontal healing of mandibular second molars after the removal of impacted mandibular third molars using distolingual alveolectomy and tooth division techniques. A total of 120 consecutive healthy patients who presented with bilaterally impacted mandibular third molars were included in this study. The same operator removed the impacted third molars on both sides in all patients. The third molar on one side was removed by distolingual alveolectomy using a chisel, whereas the contralateral tooth was removed by the tooth division technique using burs. Attachment level, periodontal pocket depth and bone healing distal to the mandibular second molars were assessed at 7 days, 3 months and 6 months after surgery. The results showed better periodontal healing and bone healing when distolingual alveolectomy was employed, especially in the removal of deeply impacted mandibular third molars.

Standard techniques of mandibular reconstruction aim at the restoration of function. However, the height and shape of the alveolar ridge are often neglected and reconstruction often results in difficulty in subsequent denture wear. Immediate reconstruction of the alveolar process with particulate autologous iliac bone is described, a technique used in 10 patients since 1978.

Two examples are presented of osteotomies performed simultaneously with surgical recontouring in cases of fibrous dysplasia of the jaws. Osteotomies are necessary when a coexistent discrepancy in jaw relationship is present. This provides a functional as well as aesthetic result. Rigid miniplate fixation was utilised, and dysplastic bone healing was uneventful, and found clinically not to differ from that of normal bone. Osteotomy is thus feasible in dysplastic bone, and may complement recontouring in achieving a better result.

Following bilateral alveolectomy, the ridge form was restored in 10 dogs with blocks of porous HA matrix and bicortical iliac autografts. The specimens were retrieved after 11 to 17 months and undecalcified sections were prepared for microscopy and histometry. Within the HA implants, bone ingrowth extended throughout the pores. This bone appeared mature and well vascularized. The autografts united to the mandible. However bone ingrowth into the cancellous spaces of the grafts was minimal or absent. Measurement of implant and graft cross-sectional areas showed the maintenance of alveolar ridge form to be equally permanent for the 2 materials over the 1.5 year duration of the study. The implant specimens were composed of 43.1% HA matrix, 45.2% bone and 11.7% soft tissue. The HA matrix had a surface area averaging 9.3 mm2/mm3 that was 91.1% covered with bone ingrowth. Although this study supported the thesis that a porous HA matrix can function as a bone graft substitute, it is noted that the unyielding nature of the implant blocks, compared to granules, requires a solution to the challenge of long-term denture support without ulceration before it can be used with clinical confidence.

The apical root resection of mandibular molars is an operation seldom performed and then one limited primarily to the lower first molars. Although the first paper on this topic was published at the beginning of the 20th century, little progress has been observed since then. This is due to the thickness of the buccal bony plate in the lower molar region which makes surgery very difficult and leads to a substantial loss of bone. The resultant limitation of the operating field prevents good vision. The aim of our approach is to minimize or to eliminate these problems by opening a bony lid above the roots which are to be resected. This can be made large enough for the surgeon to have easy access and good vision during apical surgery. At the end of the operation the same lid is replaced in order to avoid a bony defect and to facilitate the healing process. Of the 75 patients treated using this technique during a 3-year period, only one post-operative complication has been observed. A complete healing of the bone was observed in the majority of cases within 6 months.