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Biomedical subjects

J H Koumjian

Publications and source records attributed to J H Koumjian.

13 recordsLinked to original sources
PubMed1999

Classification system for complete edentulism. The American College of Prosthodontics.

The American College of Prosthodontists has developed a classification system for complete edentulism based on diagnostic findings. These guidelines may help practitioners determine appropriate treatments for their patients. Four categories are defined, ranging from Class I to Class IV, with Class I representing an uncomplicated clinical situation and a Class IV patient representing the most complex and higher-risk situation. Each class is differentiated by specific diagnostic criteria. This system is designed for use by dental professionals who are involved in the diagnosis of patients requiring treatment for complete edentulism. Potential benefits of the system include: 1) better patient care, 2) improved professional communication, 3) more appropriate insurance reimbursement, 4) a better screening tool to assist dental school admission clinics, and 5) standardized criteria for outcomes assessment.

Alveolar Bone Loss↗
PubMed1992

Mandibular complete denture impressions with fluid wax or polysulfide rubber: a comparative study.

Some authors have stated that wax cannot be used to make impressions for complete dentures, while others have found that wax has some advantages over elastomeric impression materials. The purpose of this study was to compare mandibular impressions made with a fluid wax to those made with light-body polysulfide rubber. Fifteen maxillary and mandibular complete dentures were made using fluid wax as a final impression material. For comparison, 15 maxillary and mandibular complete dentures were made using light-body polysulfide rubber. The number of adjustments required over 1 year was recorded. No statistical difference in adjustments was noted between the two groups.

Aged↗
PubMed1992

An appliance to correct mandibular deviation in a dentulous patient with a discontinuity defect.

The mandibular discontinuity defect is one of the most difficult problems in prosthetic dentistry. This article describes an appliance that has been used successfully in reducing or correcting the deviation in dentate patients who have experienced mandibular resection. It consists of a prefabricated integrated tube and plunger that are hinged to clear acrylic resin maxillary and mandibular appliances.

Acrylic Resins↗
PubMed1991

Color stability of provisional materials in vivo.

Color stability of provisional restorations is an important quality of the resin used, particularly for extensive reconstruction over a long period of time. This study evaluated the in vivo discoloration of seven resins over a 9-week period. Resin specimens were prepared and placed in the facial flange of maxillary complete dentures and the lingual flange of mandibular complete dentures. Patients were given toothbrushes and toothpaste and told not to use any chemical agents for cleansing the dentures. Observations were made at 1, 5, and 9 weeks. No change was detected at the first two evaluations. At the 9-week evaluation, four materials, True Kit, Duralay, Trim, and Protemp, showed significantly less staining than did the other three resins tested. All materials tested were acceptable from the standpoint of color stability for short term (5 weeks or less) provisional restorations. Therefore, the dentist using provisional restorations for a short period of time may consider other properties of the materials, such as resistance of fracture, marginal accuracy, ease of fabrication, and cost.

Acrylic Resins↗
PubMed1991

Tissue-integrated prostheses on malaligned implants in a partially edentulous patient: a clinical report.

Whether the result of technical errors or anatomic aberrations, malalignment of osseointegrated implants can create significant difficulty for the restorative dentist who fabricates the final tissue-integrated prosthesis. As a result, the planned prosthesis may defy completion or the implants may have to be left buried. This clinical report illustrates a solution to fabricating a fixed/detachable tissue-integrated prosthesis on malaligned posterior mandibular implants.

Aged↗
PubMed1990

Evaluation of fracture resistance of resins used for provisional restorations.

Fracture resistance of provisional restorations is an important concern for the restorative dentist. Fracture resistance of a material is directly related to the transverse strength. This study evaluated the transverse strengths of provisional resins under varied conditions. Uniform samples were made from seven resins and tested immediately after the set of the material, after 7 days of dry storage, and after 7 days of wet storage. The fractured samples from the 7-day wet storage group were repaired with the same provisional material the sample was made from and fractured again to determine transverse strength for repaired samples. Five of the resins tested demonstrated statistically similar strength in the 7-day wet group. Two were found to be significantly weaker. Absorption of water resulted in a slight, but insignificant decrease in strength. Transverse strengths varied widely in the repaired group, and all materials showed a statistically significant reduction compared with the 7-day wet storage group.

Absorption↗
PubMed1990

Marginal accuracy of provisional restorative materials.

Marginal integrity is an important quality in the provisional restoration. Previous studies on marginal integrity have presented conflicting results. In addition, newly available resins are making the selection of an accurate resin for provisional restorations difficult. The objective of this study was to evaluate the marginal accuracy of seven commercially available resins by using an established indirect technique, and to evaluate the effect of water absorption on polymerization shrinkage. Eight specimens of each material were tested under three conditions: immediately after polymerization, after 1 week of dry storage, and after 1 week of storage in room temperature water. Three materials, Duralay, Cold Pac, and Snap resins, produced statistically significantly superior marginal adaptation. Water absorption appeared to compensate for continued polymerization shrinkage.

Acrylic Resins↗