Bundle bone

Abstract: Objective: To study dimensional alterations of the alveolar ridge that occurred following implant placement in fresh extraction sockets. Material and Methods: Five beagle dogs were included in the study. In both quadrants of the mandible, incisions were made in the crevice region of the third and fourth pre-molars. Buccal and minute lingual full-thickness flaps were elevated. The mesial root of the four pre-molars root was filled and the teeth were hemi-sected. Following flap elevation in 3P3 and 4P4 regions, the distal roots were removed. In the right jaw quadrants, implants with a sand blasted and acid etched (SLA) surface were placed in the fresh extraction sockets, while in the left jaws the corresponding sockets were left for spontaneous healing. The mesial roots were retained as surgical control teeth. After 3 months, the animals were examined clinically, sacrificed and tissue blocks containing the implant sites, the adjacent tooth sites (mesial root) and the edentulous socket sites were dissected, prepared for ground sectioning and examined in the microscope. Results: At implant sites, the level of bone-to-implant contact (BC) was located 2.6 0.4mm (buccal aspect) and 0.2 0.5mm (lingual aspect) apical of the SLA level. At the edentulous sites, the mean vertical distance (V) between the marginal termination of the buccal and lingual bone walls was 2.2 0.9mm. At the surgically treated tooth sites, the mean amount of attachment loss was 0.5 0.5mm (buccal) and 0.2 0.3mm (lingual). Conclusions: Marked dimensional alterations had occurred in the edentulous ridge after 3 months of healing following the extraction of the distal root of mandibular premolars. The placement of an implant in the fresh extraction site obviously failed to prevent the re-modelling that occurred in the walls of the socket. The resulting height of the buccal and lingual walls at 3 months was similar at implants and edentulous sites and vertical bone loss was more pronounced at the buccal than at the lingual aspect of the ridge. It is suggested that the resorption of the socket walls that occurs following tooth removal must be considered in conjunction with implant placement in fresh extraction sockets.

Abstract: Alveolar bone is a specialized part of the mandibular and maxillary bones that forms the primary support structure for teeth. Although fundamentally comparable to other bone tissues in the body, alveolar bone is subjected to continual and rapid remodeling associated with tooth eruption and subsequently the functional demands of mastication. The ability of alveolar bone to undergo rapid remodeling is also important for positional adaptation of the teeth but may be detrimental to the progression of periodontal disease. The anatomical structure of alveolar bone, which is quite complex, has recently been described in detail (200). Alveolar bone is composed of bundle bone (209), which is formed in layers in a parallel orientation to the coronal-apical direction of the tooth. Sharpey’s fibers extend obliquely from the thin lamella of bone that lines the socket wall and are continuous with fibers of the periodontal ligament. A thicker outer layer of bone formed of cortical plates extends from the jaw bone and forms the lingual and labial surfaces of the alveolar process and is largely made up of spongy cancellous bone. Within the cancellous bone are numerous marrow spaces, with smaller endosteal spaces present in the cortical bone. Some of the small endosteal spaces extend into, and are contiguous with, the periodontal ligament. Because of the small size and anatomical complexity of alveolar bone, relatively few studies on the cellular, and particularly the molecular, aspects of alveolar bone structure and metabolism have been performed using alveolar bone itself. However, the ability of bone cells derived from adult rabbit alveolar bone to form mineralized tissue nodules with the characteristics of bone has been described (142, 224). A procedure has also recently been developed for the isolation of adult human alveolar bone cells, from 2-week-old osteogenic tissue recovered from dental implant surgery, that form bone tissue in culture (174). While these systems provide a means of investigating specialized aspects of the molecular

Abstract: Objective: To investigate the biologic effects of Corticision on alveolar remodeling in orthodontic tooth movement Materials and Methods: In this study, 16 cats were divided into 3 groups: group A, only orthodontic force (control); group B, orthodontic force plus Corticision; and group C, orthodontic force plus Corticision and periodic mobilization Histologic and histomorphometric studies were performed on tissue specimens on days 7, 14, 21, and 28 Results: Extensive direct resorption of bundle bone with less hyalinization and more rapid removal of hyalinized tissue were observed in group B The accumulated mean apposition area of new bone on day 28 was observed to be 35-fold higher in group B than in the control group A Conclusions: Corticision might be an efficient procedure for accelerating orthodontic tooth movement accompanied with alveolar bone remodeling

Abstract: Introduction As a consequence of extraction, the height of the buccal wall tends to decrease and results in the disappearance of bundle bone. To modify bone remodelling after extraction, various ridge preservation techniques have been proposed. The present research was drawn up with the following considerations in mind: to evaluate and to compare changes of hard and soft tissues in post-extraction sockets which received a ridge preservation procedure, with post-extraction sockets which had healed naturally. Materials and methods Each patient was randomly allocated to a test or control group using a specific software package. After extraction, the sockets were carefully inspected and any granulation tissue was removed. The control sites received silk sutures to stabilize the clot without any grafting material. The test sites were grafted with corticocancellous porcine bone and a collagen membrane. All experimental sites had the membranes left exposed to the oral cavity with a secondary wound healing. The thickness of the buccal alveolar bone, if present, was carefully measured at the time of tooth extraction using a calliper at 1 mm from the edge of the wall. The following clinical parameters were evaluated at baseline and after 4 months at implant placement: vertical bone changes, horizontal bone changes and width of keratinized gingiva. The length, diameter and need for additional bone augmentation were assessed for both groups at the time of implant insertion. Results The control group showed vertical bone resorption of 1 ± 0.7 mm, 2.1 ± 0.6 mm, 1 ± 0.8 mm and 2 ± 0.73 mm at the mesial, vestibular, distal and lingual sites respectively. Moreover, changes in horizontal dimension showed an average resorption of 3.6 ± 0.72 mm. The test sites showed a horizontal bone remodelling of 0.3 ± 0.76 mm, 1.1 ± 0.96 mm, 0.3 ± 0.85 mm, 0.9 ± 0.98 mm at the mesial, vestibular, distal and lingual sites respectively. The horizontal bone resorption at the test sites was 1.6 ± 0.55 mm. The keratinized gingiva showed a coronal shift of 0.7 mm in the control group when compared to 1.1 mm in the test group. In addition, 42% of sites in the control group required an additional bone augmentation at implant placement, when compared to 7% in the test sites. Conclusions This study clearly points out that an alveolar ridge preservation technique performed with collagenated porcine bone and a resorbable membrane – according to the procedure reported in this study – was able to limit the contour changes after tooth extraction. Finally, the test sites showed a better preservation of facial keratinized tissue when compared to control sites; grafted sites allowed the placement of longer and wider implants when compared to implants inserted in non-grafted sites.