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.     

Follow-up evaluation of 105 patients with myofascial pain-dysfunction syndrome.

A follow-up study of 118 patients was performed to determine the effect of various conservative treatments for MPD after six months to 12 years. Of the patients, 82% were females; 62 were females younger than 40 years old. During treatment, patients were made aware of muscle spasm, and consciousness of the role of muscles in MPD was raised. Of 105 patients who were contacted, 65 had no further problems, 26 thought the problem was improved and under control, and 14 had not improved or had sought treatment elsewhere. Musculature and psychological factors play major roles in the MPD syndrome.     

The prevalence of consolidated salivary deposits in the small ducts of human submandibular glands.

Deposits of apparently solid material were observed in the small salivary ducts in a series of non-diseased submandibular glands obtained from necropsies evenly divided by sex and adult age. The deposits were of granular or laminated structure. They were of mixed staining, the majority being predominantly eosinophilic. A small number of deposits were essentially wholly hematoxylinophilic and some of these were probably calcified. The prevalence of deposits, expressed as the number per unit sectional area, increased steadily with increasing age but was unrelated to sex. An apparently close correlation between intraductal salivary deposits and foci of obstructive adenitis in the same series of glands was shown to be mainly due to the common influence of age. The deposits probably form by precipitation of salivary glycoprotein, possibly because of parenchymal age changes. They may be related to early salivary lithogenesis but the statistical evidence of this study suggests that they are unlikely to be a major factor in the etiology of focal obstructive adenitis.     

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.     

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.     

Caries experience as predictor for caries incidence

The caries increment (filled surfaces) from the ages 7 to 15 years were compared in children with three or fewer (low prevalence group) or eight or more filled surfaces (high prevalence group) at the age of 8. The children participated in a fortnightly fluoride mouthrinsing program (10 ml of 0.2% NaF). Following 8 years of dental treatment and caries prophylaxis, the caries increments were 11.4 (s.d. = 7.7, n = 23 subjects) and 17.1 (s.d. = 9.6, n = 39 subjects) surfaces, i.e. significantly different (t = 2.376). Significantly (t = 4.034) more fillings had been required in the high than in the low prevalence group (31.1 +/- 17.1 vs. 15.5 +/- 9.6). The "risk group" could be identified at the ages of 7 to 8 by high caries prevalence and high ratio fillings/caries increment. Social class and number of teeth accounted more for the initial caries prevalence than for the caries increment. Correlation analyses revealed a significant, but not strong (r = 0.50), association between caries prevalence at the age of 7 and increment of fillings.