Follow-up investigation of reconstruction of the alveolar process in the atrophic mandible.

In this article the results are presented of the reconstruction of the alveolar process with iliac crest bone grafts in 14 patients. In all cases in a second operation a vestibuloplasty and a floor-of-mouth plasty was done. After an average follow-up period of 39 months, almost complete resorption of the bone grafts was observed. The clinical results varied. To obtain better results and avoid complications like pain at the donor and graft sites, mental nerve disturbances and other major problems associated with bone grafting, we prefer to perform the visor osteotomy in the future.     

Transmembrane potentials of osteoblasts.

Transmembrane potentials were recorded in situ from osteoblasts on the parietal bones of albino rat pups, 3 to 24 days of age. Osteoblasts exhibit a uniquely low polarization of their cell membranes (3.93 mV, inside negative). Osteoblasts respond rapidly, but transiently, to parathyroid hormone by depolarization, and to thyrocalcitonin by hyperpolarization.     

Longitudinal analysis of growth of the soft palate and nasopharynx from six months to six years.

Between the ages of six months and six years, longitudinal lateral headfilms were taken on 54 patients with palatal clefts or with unilateral and bilateral clefts of the lip and palate. They were measured and were compared to data on both normals and subjects with clefts of the lip only. The objectives of the study were: 1. To sutdy the effects of palatal surgery on the growth of the soft palate. 2. To compare the growth of the soft palate and nasopharynx among the patients with various types of clefts and normals. 3. To study the growth acceleration or so-called catch-up growth after palatal surgery at various ages. (Anterior palatal surgery at 14 months +/- 2 months. Posterior palatal surgery at 16 months +/- 2 months.) 4. To evaluate the relationship between velopharyngeal growth in cleft groups and voice quality.     

Evaluation of the use of freeze-dried skin allografts in the treatment of human mucogingival problems.

The purpose of this investigation was to evaluate the clinical responses to freeze-dried skin allografts when used to correct mucogingival problems in humans. FDS was obtained by the NMRI Tissue Bank after processing by standard procedures. The recipient sites were prepared using the standard partial thickness dissection with apical periosteal separation. Rehydrated FDS was sutured into place to completely cover the recipient sites. Routine postoperative procedures were performed. Evaluations were made by means of calibrated periodontal probe measurements, Kodachromes, and radiographs preoperatively and up to 12 months postoperatively. Fourteen patients received 24 FDS allografts over a total of 56 tooth sites. All treated teeth showed a substantial increase (greater than 2 mm) in the width of the zone of keratinized gingiva at all postoperative time periods (2.88 +/- 1.57 mm at 12 months). Other findings included a mean gain of attachment of 0.40 +/- 1.08 mm, a mean decrease in recession of 0.12 +/- 0.91 mm, and mean decrease in pocket depth of 0.33 +/- 0.53 mm. Patient comfort was good, and there were no untoward sequelae, even in patients receiving multiple grafts. This study indicates that FDS allografts are an acceptable and beneficial material for treatment of mucogingival problems in humans.     

Oral health status of institutionalized elderly Cape Coloreds from the Cape Peninsula of South Africa

A study has been conducted to assess the oral health status and need for dental treatment among elderly Cape Coloreds resident in homes for the aged in the Cape Peninsula of South Africa. This paper describes the prevalence of diseases of the mouth with special reference to denture-induced lesions and white lesions of the oral mucosa. Dental caries was the most prevalent oral lesion (27.2%). The most common conditions of the soft tissues were leukoedema (24.4%) and leukoplakia (4.4% for the tongue; 20.4% for the remainder of the oral mucosa). Leukoedema and leukoplakia showed statistically highly significant correlations with tobacco habits. Men more commonly had a tobacco habit than women (P less than 0.002) and leukoplakia, leukoedema and depigmented lesions of the lips were significantly more common in men than in women. No significant difference could be proven statistically when the frequency of irritative fibrous hyperplasia in females was compared with that in males.     

Effects of cement bases on the stresses and deflections in composite restorations.

A model was used to investigate stresses and deflections in cement bases and in a composite restorative material induced in a posterior Class I restoration. Deflections in the composite were highest when it was supported by a base with a low modulus; however, the maximum tensile stress (12 MN/meter2) occurring in the composite restoration at the interface with the base was well below the maximum tensile strength of most composite materials (30 to 40 MN/ meter2). Tensile and shear stresses occurring in the cement bases were of sufficient magnitude to exceed the strength of the cement when a 1.5-mm layer of zinc phosphate cement (base consistency) was supported by a 0.5-mm layer of ZOE lining material. Lowest values of stress were observed when a 2-mm layer of a zinc polyacrylate base was used to support the composite restoration. An ideal situation would be to have a cement base with a modulus of elasticity equal to that of the composite material. Finally, the maximum stress and deflection values obtained here can be easily exceeded in a clinical situation when wider variations can be easily introduced, making the choice of a cement with the proper modulus even more critical.     

Facioskeletal remodelling resulting from rapid palatal expansion in the monkey (Macaca cynomolgus)

Previous studies have established that rapid palatal expansion does open the midpalatal suture. The purpose of this study was to demonstrate the gross architectural changes in the facio-skeletal structures of four cynomolgus monkeys produced by the palate-splitting appliance. Bone changes were demonstrated by the utilization of tetracycline vital staining and ultraviolet light-excited fluorescence of new bone formed during an episode of skeletal remodelling.Findings indicated extensive remodelling had occurred in the nasal cavity, lateral alveolar processes, inferior surface of the palate, and the floor and lateral and medial walls of the orbits. Lateral orbital changes terminated at the zygomatico-frontal suture anteriorly, and fronto-sphenoidal suture posteriorly. Medially, changes were limited to the structures below the fronto-ethmoidal and fronto-nasal sutures. Thus, the roof of the orbits formed by the frontal bone was unaffected by the procedure of maxillary expansion, indicating that all changes in the facial skeleton were restricted to the appendymal structures of the neurocranium. The cranial base remained unchanged.