Dehiscences and fenestrations: methodological care necessary to avoid errors in diagnosis and measurement.

The low prevalence of gingival recessions observed in orthodontic clinical practice may be assigned to the fact that in studies in which dehiscences and bone fenestrations are described as frequent, they were diagnosed based on: 1) dry skull studies; 2) areas with periosteal reflection together with flap; and 3) imaging techniques with low sensitivity to detect these defects, which have a delicate structure and function. In areas of pseudo-dehiscences and fenestrations, the periosteum and the alveolar cortical bone are very thin; also, they either have been removed during preparation of the dry specimens in the areas for analysis, or, alternatively, have not been investigated using an ideal imaging method.

Dehiscences and fenestrations: methodological care necessary to avoid errors in diagnosis and measurement

ABSTRACT The low prevalence of gingival recessions observed in orthodontic clinical practice may be assigned to the fact that in studies in which dehiscences and bone fenestrations are described as frequent, they were diagnosed based on: 1) dry skull studies; 2) areas with periosteal reflection together with flap; and 3) imaging techniques with low sensitivity to detect these defects, which have a delicate structure and function. In areas of pseudo-dehiscences and fenestrations, the periosteum and the alveolar cortical bone are very thin; also, they either have been removed during preparation of the dry specimens in the areas for analysis, or, alternatively, have not been investigated using an ideal imaging method.

RESUMO A ausência de prevalência elevada das recessões gengivais relacionadas à prática clínica ortodôntica se explica, provavelmente, porque, nos trabalhos em que as deiscências e fenestrações ósseas são descritas como frequentes, essas foram diagnosticadas a partir de: 1) estudos em crânios secos; 2) áreas com rebatimento periosteal junto com o retalho; e 3) uso de métodos imagiológicos que falham em sensibilidade para captá-las, pela sua delicadeza estrutural e funcional. Nessas áreas de pseudodeiscências e fenestrações, existe periósteo e cortical óssea alveolar muito fina, que foram eliminados nos procedimentos de preparação dos espécimes secos, nas áreas para a análise ou, então, não se aplicou um método imagiológico ideal.

Single photon emission computerized tomography and histological evaluation in the validation of a new technique for closure of oro-antral communication: an experimental study in pigs.

Various bone regeneration techniques have evolved recently but controversies regarding vascularization and integration of such bone grafting techniques have led occasionally to animal experiment to validate such techniques. The objective of this study was to evaluate the evidence of vascularization and osseo-integration of a new bone regeneration technique utilized for the closure of oro-antral communication (OAC) by an experimental model in which Single Photon Emission computerized Tomography and histological studies were conducted in pigs. We conclude that the sandwich technique used for the closure of OAC results in a vascularized new bone formation which eventually osseo-integrate with the surrounding bone. Also, this experimental study confirmed that autogeneous bone graft was superior to xenografts when used within the sandwich unit.

Biological assessment of porous-implant hydroxyapatite combined with periosteal grafting in maxillary defects.

PURPOSE: To investigate the use of porous hydroxyapatite (HA) combined with periosteal graft to repair an induced maxillary bone defect. MATERIALS AND METHODS: A defect was produced in the premaxillary bone of rats. Four groups were used: 1) those treated with the mucoperiosteal graft from the premaxilla; 2) those treated with HA combined with mucoperiosteal graft from the premaxilla; 3) those treated with HA combined with periosteal graft from the femur; and 4) those treated with periosteal graft from the femur. RESULTS: The radiographic aspects from all groups showed no signs of bone formation after 2 weeks. After 16 weeks, there was evidence of points of radiolucency inside the HA implants. Cell proliferation occurred from the periosteum covering the defect. Bone tissue grew from the defect margin to inside the defect in all cases. Mature bone was seen around the HA implants after 8 and 16 weeks. CONCLUSION: The periosteal graft provides satisfactory support to the HA implant, allowing the growth of new bone.

Aggressive lesion in osseous sarcoidosis.

We describe an unusual aggressive lytic bone lesion with "sunburst/hair-on-end" periosteal reaction in a patient with surgically proven osseous sarcoid and review the pertinent literature.

Haemoglobin SC disease in Jamaica

A skeletal survey was carried out on 84 cases of haemoglobin SC disease. The radiological features noted were increased translucency of bone, abnormal trabecular pattern, medullary expansion, wide vascular channels in phalanges, and radiological evidence of infarction, both medullary and cortical. The frequency of bone lesions thus demonstrated increased with age. The most characteristic lesions in this region were those of vascular necrosis; contributing factors such as the high haemoglobin level characteristic of the condition are discussed. An interesting feature was the lack of correlation betweeen clinical severity and degree of radiological change. (AU)

Sickle cell beta thalassaemia in Jamaica

An analysis of the radiological appearances in a skeletal survey of 48 patients in Jamaica with sickle cell beta thalassaemia is presented. The appearances are similar to those in homozygous sickle cell disease and SC disease and a confident distinction between the conditions on radiological grounds alone is likely. (AU)

Radiological changes associated with leg ulcers in the tropics

The radiological changes associated with four distinct types of leg ulceration common in the tropics are reviewed. Only mild changes occurred in the tropical phagedenic group, but more marked radiological abnormalities occurred in the three chronic groups. The frequency and pattern of the periosteal reaction is the most useful guide to radiological differentiation of these groups. (AU)