Quintessence International, 06/1993

This double-blind, randomized, controlled clinical trial was designed to evaluate the efficacy and soft tissue effects of nightguard (mouthguard) vital bleaching. Subjects were assigned to one of two treatment groups, overnight (insertion of mouthguard at bedtime) or 3-hour (replenishment of test solution at hourly intervals for a total of 3 hours exposure daily). The experimental solutions included two products that are specifically designed for tooth bleaching, one product that is markedted as an oral antiseptic, and a control solution (glycerin). Each subject particpated for a 3-week period. Tooth color analysis (shade determination) was done at baseline and the end of the treatment. Gingival and Plaque Indices were recorded at baseline and at the end of each week of study. Results indicated that the bleaching treatment was effective in most cases and caused no tissue inflammation or significant tooth sensitivity. The mean Gingival and Plaque Indices were generally lower (denoting improvement) at the end of treatment. Patient satisfaction with the procedures was high.

Bonded composite resin can be used for restoration of certain teeth with posterior proximal carious lesions. Successful restoration depends on careful tooth isolation, proper dentin and enamel bonding methods, selection of an appropriate composite resin, and ideal handling of all the restorative materials. This paper details a procedure for placing a mesio-occlusodistal bonded composite resin restoration in a maxillary premolar.

The intensity of light within the wavelengths of 400 to 500 nm on a dental photocurable resin restorative material is a vital factor affecting many of the physical and chemical properties of the resulting restoration. This paper compares the precision of two recently introduced hand-held radiometers. The results indicate that the response of both hand-held meters was linear. For a given amount of decrease in light source intensity, both hand-held units responded with a corresponding decrement in measured intensity value. Both hand-held meters were found to limit their pass band of intensity readings between 400 and 515 nm, making them very useful clinical instruments. However, the absolute intensity readings between the two units were significantly different.

An alternative tooth replacement system, based on pin retention, was clinically evaluated for up to 4 years in a prospective study. Thirty-two Universal Dental Anchorage anchors, supporting 28 fixed partial prostheses in 25 patients, were placed. Most of these prostheses had a cast complete crown on one abutment; on the other abutment, the UDA anchor functioned as a support for the extension pontic. After a mean observation period of 2 years, nine anchors failed. Around five of the failed anchors, caries was present; this occurred after 2 years or more of function of the prostheses. Early failures (4/9) were registered in the first year of function and were caused by loss of retention (three) or anchor fracture (one). The peridoontal condition of the UDS anchor abutment teeth was not significantly different from that of the contralateral side. The number of failures, espcially the number caused by recurrent caries, is cause for concern.

This study evaluated the effect of selected luting media on the compressive strengths of two types of all-ceramic crown. Tooth preparation was standardized; each preparation had a shoulder width of approximately 1.2 mm, and all internal preparation angles were rounded. Hi-Ceram and Dicor all-ceramic crowns were fabricated and cemented into the preparations with zinc phosphate, glass-ionomer, or composite resin cement. Coronal compressive fracture strengths were determined, using a set of unrestored teeth as a control. There were no statistically significant differences among the mean compressive strengths of the three luting media, and there was no statistically significant difference between the mean compressive strength of Dicor and that of the natural tooth control.

Occupation-related health complaints were investigated among 101 women and 100 men employed in dental technology in Norway. In technicians older than 30 years, there were no age-related differences in frequency of self-reported health complaints. Gender-related differences in responses were limited to specific musculoskeletal symptoms. About half of the employees had experiences some kind of job-related health problem, among which musculoskeletal and dermal reactions were common (39% and 28%). Other health problems were respiratory (16%), systemic (16%), sensory (10%), or neurologic (7%). Ergonomics and work-specific stress factors were important etiologic factors for the musculoskeletal reactions, whereas chemical factors of dental material origin were realted to the other ractions. Comparison of the present results with corresponding data from other occupations indicated that the duties of a dental technician combine the risk of ergonomically induced musculoskeletal reactions characteristic of manual labor with the risk of chemically induced reactions.

With few exceptions, most cases of external apical root resorption have no evident etiology, particularly when root blunting from orthodontic treatment has been ruled out. This study determined the frequency of apical root resorption in the permanent dentition of patients who had not been treated orthodontically. Associations between the occurrence of external apical root resorption and three measures of oral health-number of missing teeth, periodontal probing depths, and alveolar crestal bone heights-were also examined. Between 7% and 10% of the 306 patients exhibited obvious apical resorption. Strong statistical associations were found between the occurrence of external apical root resorption and loss of teeth, increased periodontal probing depths, and reduced crestal bone heights; ie, root resorption was significantly more common in teeth with compromised support. Loss of stability from adjacent teeth, increased use of fewer remaining teeth, and loss of the root's anchorage in the bone are significant predictors of external apical root resorption.

Ten mesio-occlusodistal composite resin inlays were fabricat by the indirect method and cemented in extracted posterior teeth. The restorations were subjected to thermocycling and subsequently placed in a 50% silver nitrate solution. Specimens were prepared and inspected under a stereoscopic mic roscope and a scanning electron microscope. The results showed a total absence of microleakage at the margins terminating in enamel and a slight degree of microleakage in only two margins terminating in cementum. This corresponded with the general absence of defects and gaps that was observed in the scanning electron microscope. The exception was in the two specimens that exhibited dye penetration; these were found to have material in the marginal areas.

The baisc 35-mm camera equipped with a 90-, 100-, or 105-mm macro lens, which is already used in many dental offices, has the potential to create good title slide transparencies for use in study club presentations, table clinics, and academic lectures. Several photographic film products are now available that place this well regarded medium of dental education within the capability of the average motivated practitioner. In this overview, Kodalith, Vericolor SO-279, PolaBlue, Polachrome HCP, and Polagraph systems are analyzed and compared for time efficiency, cost effectiveness, and quality of slides produced.