Frozen autogenous mandible as an immediate replacement graft.

A study in animals was designed to examine the feasibility of grafting autogenous frozen mandible. Two groups of animals were used. In the first group, periosteum was elevated from the bone before resection. In the second group, the periosteum was removed with the resected specimen. Osteogenesis was shown by clinical, radiographic, fluorescence, and histologic studies in both groups of animals. The same technique was performed in nine humans with carcinomas that involved the mandible. The results were encouraging. We believe that immediate or delayed reconstruction with autogenous frozen mandible in a patient undergoing ablative surgery of the head and neck with involvement of the bone may offer the patient, as well as the surgeon, another acceptable treatment modality.     

Improvements in bracket base design

Acid etch bonding of orthodontic attachments to the labial and lingual surfaces of teeth is generally adequate for clinical service. Failures do occur, and these are related to technique problems in acid etching or resin manipulation or to bracket base design. The widely used foil mesh base can present problems in retention because of design defects or corrosion. Improvement in mechanical retention of resin to the attachment base would result in significant improvements in bonding and fewer clinical failures. One of our approaches to improved retention is to fuse metallic or ceramic particles onto the bracket base so as to achieve a particulate or porous layer into which resin can penetrate. The results of bond-strength tests showed that a 100 percent increase in bond strength could be obtained with sintered porous metal-coated brackets. Further development is proceeding.     

Tritiated thymidine autoradiographic study of the effects of inferior alveolar nerve resection on the proliferative compartments of the mouse incisor formative tissues

At 15, 30 and 60 days after denervation, 10 mice were injected (5 controls, 5 denervated) at each time period with 0.5 μCi/gm of [³H]-thymidine. Denervated teeth, after 15 and 30 days, were thinner, shorter and narrower with a chalky-white appearance; by 60 days, the teeth returned to their normal predenervated appearance. The responses of the proliferative compartments of the mouse incisor varied with time after denervation, and depended on whether comparison was made to sham controls or the control side of a denervated mouse. The pre-odontoblasts were most stable in terms of [³H]-thymidine labelling index with a significant decrease only at 60 days after surgery. This decrease may be due to an alteration of the inductive influence of the inner enamel epithelium and the nerve resection. The effects of nerve, resection on the inner enamel epithelium were a reduction in the labelling index on both control and denervated sides in comparisons to sham controls and a decrease in labelling index of the denervated side when compared to contralateral control. Significant differences between the control and denervated sides of experimental mice were evident 15 days after denervation in the outer enamel epithelium, inner enamel epithelium, and pulp fibroblasts. Indirect effects (i.e. chipping of the teeth) may mask neurotrophic influences. There also appears to be a homeostatic or compensatory mechanism for attenuation of the effects of denervation in continuously erupting teeth. The effects at the early time periods emphasize the need for a study of neurotrophic effects on the cellular compartments of the tooth in the period immediately following denervation.     

Growth and acid tolerance of human dental plaque bacteria

Pure cultures of representative strains of cariogenic and non-cariogenic plaque bacteria were assessed for their ability to initiate and maintain growth in broths, adjusted to initial pH levels of 7.0, 5.5 or 5.0, and to produce lactic acid from sucrose or glucose in resting-cell suspensions at pH 6.5, 5.0, 4.5 and 4.0. Streptococcus mutans, Lactobacillus casei and Streptococcus faecalis showed greater acid tolerance than strains of Streptococcus sanguis, Streptococcus salivarius, Streptococcus mitis and Actinomyces viscosus. For all species, growth initiation in broth was more acid sensitive than lactic-acid production in resting-cell suspensions. These data confirm and extend previous observations that the species of plaque bacteria most closely associated with the initiation or progression of dental caries are more aciduric than non-cariogenic species.     

Temporomandibular degenerative joint disease. Part II. Diagnostic procedure and comprehensive management.

The diagnostic procedure is given in the detail necessary to arrive at an accurate diagnosis of temporomandibular degenerative joint disease (TDJD). The differentiating clinical findings of degenerative joint disease (DJD) and rheumatoid arthritis of the temporomandibular joint (TMJ) are described. Principles and modalities of comprehensive management of TDJD are presented in the manner and sequence needed to allow practical clinical application. Methods of treatment are applied to the management of patients with acute and chronic TDJD. The surgical procedure for TDJD, intracapsular high condylectomy with a preauricular incision, is described in the detail required for individual application. Case reports are presented to illustrate the comprehensive management of TDJD.     

Results with multi-band appliances in the treatment of class II]

Corrections of Angle's Class II malocclusions constitute nearly 1/4 of the treatments performed by the orthodontist. The author studied the results achieved with treatment methods applicable to these malocclusions and compared them with those obtained by means of multiband appliances. On the basis of 2,110 cases, he establishes the indications for the use of multiband appliances in the framework of social dental treatment.