Fibroblast subpopulations in intra-oral wound healing

The objective of this study was to characterize fibroblasts at sequential time points during intra-oral wound healing in the rat. Experimental wounds were made at several time points in the mucoperiosteum of the palate of 35-day-old Wistar rats. Fibroblasts were cultured from the biopsies under standard conditions for the same number of passages. The expression of the integrin subunits alpha 1, alpha 6, and beta 1; and the intermediate filaments alpha-smooth muscle actin and vimentin were analyzed by flow cytometry. Western blot analysis was performed at 0, 8, and 60 days postwounding to confirm the expression of both intermediate filaments. The phenotypic profiles of fibroblasts cultured from subsequent stages in the wound healing process differed considerably. We conclude that distinct fibroblast phenotypes can be isolated from different stages in wound healing. These phenotypes remained stable during in vitro culturing. In addition, cryosections of the wound areas were made at identical time points and were immunohistochemically stained for the same antigens. The immunohistochemical staining correlated well to the flow-cytometric data. These results suggest the occurrence of multiple subpopulations of fibroblasts with a specialized function during wound healing. We hypothesize that undesirable consequences of wound healing might be prevented through the modulation of specific fibroblast subpopulations.     

Unusual root formation in a premolar with dens evaginatus

An unusual case of dens evaginatus is reported in which root formation was anomalous and incomplete. The possible aetiology of the anomaly is discussed and the treatment of teeth with dens evaginatus is reviewed.     

The stability of double jaw surgery: A comparison of rigid versus wire fixation

The subjects of this study were 35 patients who underwent simultaneous surgery for superior repositioning of the maxilla and advancement of the mandible. They were studied cephalometrically for a comparison of the postsurgical stability of two commonly used fixation techniques: (1) rigid fixation with bone plates and (2) skeletal-wire fixation. One surgeon performed the operations on all 35 patients, and both groups were studied for an average of 15 months after surgery. Results showed that, although the maxilla remained relatively stable after surgery with both fixation techniques, rigid fixation tended to improve stability, primarily by eliminating relapse in excess of 2 mm. Mandibular stability was much greater with rigid fixation: the amount of relapse of the horizontal projection of B point with this method was 6%, while in the skeletal-wire sample it was 26%. Increased rotational stability between the proximal and distal segments of the mandible appeared to be a major factor in the improved overall stability of the rigid-fixation sample. The amount of mandibular relapse was found to be correlated to the amount of advancement in the wire-fixation sample, but not in the rigid-fixation sample.     

Factors Affecting the Strength of Denture Repairs

Fracture of dentures is a common clinical finding in daily prosthodontic practice, resulting in great inconvenience to both patient and dentist. A satisfactory repair should be cost-effective, simple to perform, and quick; it should also match the original color and not cause distortion to the existing denture. Different repair materials, surface designs, and mechanical and chemical surface treatments have been recommended in order to obtain stronger repairs. This article reviews some of the available literature with regard to the most important factors that may influence the strength of denture repairs.     

The Enforcement of Regulations Restricting Expanded Duties by Dental Auxiliaries: an Analysis of the Recent Disciplinary Actions of the Texas State Board of Dental Examiners

The issue of delegation of dental procedures (expanded duties) to auxiliaries continues to be controversial. Although it has been shown that these practices are usually beneficial to the public, many states continue to maintain laws prohibiting expanded duties. In Texas, auxiliaries are not allowed to perform many simple functions, and dentists who supervise these acts are tried and sentenced by the Texas State Board of Dental Examiners. Although one might expect that more serious categories of offenses would be treated in a harsher manner, this study indicates that this is not the case in Texas. The disciplinary actions of the Texas State Board of Dental Examiners were analyzed, and the rate of conviction and severity of penalty for three types of offenses: supervising auxiliaries in the performance of unauthorized expanded duties, malpractice/negligence, and drug offenses were compared. The results revealed that dentists who were convicted for unauthorized auxiliary expanded duty use were assigned harsher penalties than those given to dentists convicted for other classes of offenses (P = .02, Fisher's exact test). This study indicates that, at least for the dentists of Texas, the punishment may not always fit the crime.     

Substance P-induced histamine release from rat peritoneal mast cells and its inhibition by antiallergic agents and calmodulin inhibitors.

Substance P-induced histamine release and Ca2+ release from the intracellular Ca store of rat peritoneal mast cells were inhibited by both antiallergic drugs and microtubule inhibiting agents. It was found that in the case of antiallergic compounds, histamine release inhibition may be intimately related to the inhibition of Ca2+ release from the intracellular store in which the microtubules play an important role. When mast cells were pretreated with either theophylline or dibutyryl cAMP, the inhibition of histamine release was closely related to the inhibition of Ca2+ release from the intracellular Ca store. Calmodulin inhibitors were also effective in inhibiting histamine release from mast cells induced by substance P. The inhibitory potencies of calmodulin inhibitors on histamine release from mast cells were closely correlated with those exerted on calmodulin activity.