Homer C. Jamison

The apical seal via the retrosurgical approach: II. An evaluation of retrofilling materials☆

In this investigation heat-sealed gutta-percha (A) reinforced with Adaptic (B), ASPA (C), Cupralloy without (D) and with (E) varnish, Spheraloy without (F) and with (G) varnish were used as retrofilling materials. Seventy maxillary central incisors with Class I canal anatomy were selected. Marginal leakage at the apical filling/root canal interface was evaluated quantitatively by means of a fluorescent dye technique. All statistical tests were computed at the 5 percent level of significance. Analysis of variance revealed that differences in microleakage among retrofillings were significant. Tukeys test of multiple contrasts was used to isolate statistically significant differences between all pairs of means. The following results were obtained: D F A G E C B Retrofillings are ranked in descending order of microleakage. Means that are linked were not significantly different.

A study of the relationship of the dental midline to the facial median line

This report presents the results of an original investigation designed to determine (1) the prevalence in the natural dentition of a maxillary midline located in the exact middle of the mouth using the philtrum as the most reliable guide and (2) the percentage of people in whom the maxillary and mandibular midlines precisely coincide with each other. Results indicate that the midline is situated in the exact middle of the mouth in approximately 70% of people and that the maxillary and mandibular midlines fail to coincide in almost three fourths of the population.

Effect of cavosurface treatment ,on marginal leakage in Class V composite resin restorations

Under the experimental conditions used in this in vitro study, the following conclusions may be drawn: 1. Etching of the enamel walls in butt and beveled preparations significantly reduces incisal marginal leakage. 2. The application of a low-viscosity bonding resin to the etched enamel walls of preparations prior to the insertion of the composite resin is not necessary to obtain minimal incisal leakage at the composite resin/etched enamel interface. 3. Cavosurface configuration has no significant effect on incisal marginal leakage. 4. Cavosurface configuration and the restorative techniques used in this study affect the degree of gingival microleakage to some extent but do not eliminate it.

An optimal concentration of phosphoric acid as an etching agent. Part I: Tensile bond strength studies

E tching enamel surfaces with phosphoric acid (H,PO,) is an accepted and widely applied technique to improve bonding of dental resins to enamel in restorative dentistry,’ in preventive dentistry,’ and for the direct bonding of orthodontic attachments.3 The concentrations recommended for clinical use range from 30% to 60%. Numerous investigations have been carried out to define the optimal concentration of H,PO, for use as an enamel etching agent. Tensile bond strength studies of dental restorative resins to enamel surfaces etched with different concentrations of H,PO, have been used for this purpose.4-‘5 The optimal concentrations of H,PO, recommended by these investigators have ranged from 8% to 65%. This study was designed to determine an optimal concentration of H,PO, as an enamel etching agent by means of tensile bond strength tests.

Effect of concentrations of phosphoric acid on enamel dissolution

E tching enamel surfaces with orthophosphoric acid (H,PO,) is an accepted and widely applied technique to improve the bonding of dental resins to enamel. It is effective in restorative and preventive dentistry, in orthodontics for the direct bonding of orthodontic attachments, and in periodontics for the stabilization of loose teeth. The optimal concentration of phosphoric acid as an etching agent for intraoral use is controversial,’ demonstrated by the fact that the concentration of H,PO, supplied with commercial dental products ranges from 30% to 60%. Various laboratory techniques have been used to estimate the optimal concentration of H,PO,. These include tensile bond strength tests, scanning electron microscopy, and the determination of the depth of etch or the amount of superficial enamel removed .by the etching procedure.2-5 Table I. H,PO, concentrations in etching solutions

A comparison of combinations of clinical and radiographic examinations in evaluation of a dental clinic population

Panoramic periapical anterior and posterior bitewing radiographic, mirror-explorer, and transillumination clinical examinations were performed on 300 patients. Various combinations of the radiographic and clinical examination techniques were compared in terms of their ability to diagnose caries, alveolar bone loss, calculus, periapical bone lesions, impacted teeth, root tips, and miscellaneous conditions. A mirror-explorer clinical examination with panoramic and posterior bitewing radiographs and either anterior bitewing radiographs or transillumination proved to be as efficient in the initial examination of patients as the mirror-explorer clinical examination with periapical and posterior bitewing radiographs.

Dental Caries Prevalence in Secondary School Students in Iraq

Caries data from 952 secondary school students in Iraq representing three geographic regions were obtained and analyzed on the basis of sex, geographic, and urban-rural differences. A DMFT of 5.47 and a DFS of 6.17 were recorded for the total sample. Greater caries experience was noted in urban residents, females, and those from the Central region.

Microleakage of selected composite restorative resins

Abstract Five selected composite restorative resins were used to restore Class V preparations in extracted human maxillary canine teeth. In addition, a low-viscosity bonding resin was used in conjunction with one of the restorative resins. Microleakage, at both the incisal and cervical margins of the restorations, was assessed by means of a radioisotope after the restored teeth had been subjected to 2500 cyclic temperature changes at 5° and 55°, respectively. Incisal microleakage was not significantly different but severe microleakage was recorded at the cervical margins of the restorations.

Surface topography of the enamel margins of butt and beveled Class V preparations

A major shortcoming of the composite restorative resins is that they do not adhere to enamel and dentin.’ The alteration of tooth surfaces by acid conditioning with phosphoric acid increased the bonding of acrylic restorative resins to enamel,:: and the effects of phosphoric acid etching on enamel surfaces have been studied extensively with the scanning electron microscope @EM). ‘-? The classic cavity preparation for silicate cement, acrylic resin, and composite resin restorations is box-shaped with internal retention and a cavosurface angle of 90 degrees resulting in a butt joint. The concept of beveling the enamel margins of conventional butt preparations to produce a cavosurface angle of 135 degrees was proposed for the following reasons: 1. A beveled margin results in improved esthetics because it provides for the gradual transition from tooth structure to composite resin.” 2. A beveled marqin provides more enamel for c acid etchinK for retentive purposes.: 3. Acid etching of a beveled enamel margin provides improved marginal seal.‘ The poor leakage results obtained in butt restorations when compared to beveled restorations were explained on the basis that bonding of composite resins to surfaces of longitudinally cut enamel prisms was not as strong as to cross-cut enamel prisms.” Microleakage studies have been used extensively to evaluate the effect of restorative techniques on the integrity of the seal at the restoration/tooth inter-

X-radiation in dental offices in Jefferson county, Alabama: II. Darkroom facilities and processing techniques

Abstract The first portion of this article reviewed the results of a survey of dental offices in Jefferson County, Alabama, in so far as darkroom facilities and processing techniques were concerned. The discussion phase of the presentation reviewed in a detailed fashion well-established fundamentals which apply to such facilities and techniques. X-radiation must be used when needed. The onus is on the practitioner not to use radiation in a useless or wasteful fashion. When inadequate darkroom facilities or techniques result in a film of less than optimum quality, the radiation used to produce that film has been used in a partially or wholly useless and wasteful manner.