A quality assessment system: the search for validity

Quality assessment and assurance should involve all of dentistry, not just third party payment plans. One evaluation system is described and a draft outline of guidelines for criteria and standards is presented. An important, and usually neglected, aspect of the use of the system is illustrated by the presentation of some quantitative data from the review of a dental care program. Concerns about the validity of various elements are discussed, together with the difficulty of establishing such validity. Nevertheless, there are indications that the system is able to distinguish among different levels of quality using a dichotomous scale. More research in the field is urged.     

Periapical status and prevalence of endodontic treatment in an adult Dutch population

This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and determined the periapical status of all teeth using panoramic radiographs. The results indicate that in this group, 2.3% of the teeth were root-filled, and that 5.2% of all non-endodonticallv treated teeth showed signs of periapical pathology. Around the apices of 39.2% of the endodontically treated teeth in this survey, radiographic signs of periapical pathology were observed. Using the level of the root canal filling as a criterion for evaluating the quality of the root canal treatment, 50.6% of the endodontic treatments were qualified as inadequate. There was a significant correlation between the presence of periapical pathology and underfilling of the root canal(s). 44.6% of the patient sample had at least one tooth with radiographic signs of periapical pathology, indicating a substantial future need for endodontic treatment.     

Polyoma virus-induced murine odontogenic tumors.

Neonatal mouse pups were injected subcutaneously with polyoma virus to induce odontogenic tumors. This treatment resulted in a spectrum of tumors that arose in organs dependent upon epithelial-mesenchymal interactions for their organogenesis, which included the teeth, salivary glands, thymus, and lacrimal glands. In addition, several odontogenic tumors with a histologic resemblance to ameloblastoma were identified and analyzed with respect to the presence of markers specific for various stages of ameloblast differentiation. Immunodetection analyses of the odontogenic tumors identified fibronectin and laminin, typical of basement membrane organization during early tooth organogenesis. These same tumors failed to express amelogenin, a gene whose expression is limited to differentiated ameloblasts. In contrast, a 47 kDa enamelin-like polypeptide was identified with the use of an antienamelin antibody. These data were interpreted to suggest that the polyoma virus truncated the differentiation pathway for these odontogenic tissues at an early stage of their development and retained the expression of basement membrane components and the enamelin-like polypeptides, yet excluded expression of amelogenin gene products. This observation suggests that polyoma viral transformation may dysregulate odontogenic tissue interactions and produce tumors composed of cells arrested at a specific stage in their development.     

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.     

Radiopacity and physical properties of titanium-polymethacrylate composite.

Titanium-polymethacrylate composite was prepared as an x-ray-opaque filler for composite core materials. The base monomers of the composite were 2,2-bis [4-(3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Pure titanium powder was used as a radiopaque element. Two functional methacrylates--isopropyl dimethacryloyl isostearoyl titanate (KR-7) and 4-methacryloyloxyethyl trimellitate anhydride (4-META)--were adopted as couplers of titanium powder. The radiopacity of composites was determined in terms of their equivalent thickness of aluminum per unit thickness of material. Compressive and transverse strengths of the composites were measured by use of coupled and untreated titanium fillers. The composites that contained 70% and 80% titanium by weight showed more radiopacity than enamel and less than amalgam. Radiopacity was controlled by the content of titanium filler in the composite. The decrease in compressive and transverse strengths of the composites was 0.7 to 15.9% and 43.7 to 52.9%, respectively, after one year's immersion in water. The decrease in transverse strength was remarkable; however, this deterioration was diminished by use of both KR-7 and 4-META as couplers for titanium. Thus, prepared titanium-polymethacrylate composite may be used as a radiopaque composite filler for self-curing composite core materials.     

Stimulation by carrageenan of arachidonate 12-lipoxygenase activity in dog gingival tissue

At 4 h after injection of carrageenan into the gingiva, the 12-lipoxygenase activity of the gingival homogenate was markedly increased. Activity in the cytosol and microsomal fractions was markedly increased when assessed as the specific activity based on nmol/min/mg of protein, and in the cytosol fraction as the percentage distribution of total activity. The 12-lipoxygenase activity in the homogenate from carrageenan-treated gingiva was not affected by either EDTA or calcium ion, or a combination of the two. 12-lipoxygenase activity in both carrageenan-treated and untreated gingiva was inhibited dose-dependently by AA861, a striking difference from its effect on platelet 12-lipoxygenase. There was a marked increase of 12-lipoxygenase activity in experimentally inflamed gingiva compared to the non-inflamed gingiva.     

DNA analysis of oral leukoplakia by flow cytometry.

DNA ploidy of 19 oral leukoplakias with and without epithelial dysplasia was investigated and the results were compared with 11 normal gingival biopsies, 14 oral benign tumours and 50 oral squamous cell carcinomas. The results suggest a possible relationship between DNA aneuploidy and oral leukoplakias or squamous cell carcinomas, as 32% of the oral leukoplakias and 48% of the oral squamous cell carcinomas were aneuploid although all the normal gingival biopsies and the benign oral tumours examined were diploid. No significant relationship was observed, however, between DNA ploidy and epithelial dysplasia in the leukoplakias.     

Mongoloid features of the permanent mandibular second molar in Singaporean Chinese

The permanent mandibular second molar is usually described as four-cusped, two placed buccally and two lingually. It has been reported that five-cusp forms were more commonly present in dentitions of mongoloid origin. The prevalence and features of this tooth form were examined in a Singaporean sample of 380 subjects with bilateral presence of the mandibular second molars. One-hundred and sixty four cases (43.1 per cent) were found to have bilateral occurrence of five-cusp forms and thirty-four cases (8.9 per cent) with unilateral occurrence. Six-cusp forms were detected in three cases. There was almost equal prevalence in both sexes and both sides were equally involved in unilateral cases. The extra cusp was smallest, placed disto-buccally and sometimes midway at the distal border. The occlusal outline of five-cusp second molars was rectangular with a somewhat similar groove pattern to the first molar. There was an increase in the mesio-distal width of the crown. The high incidence was comparable with other studies of mongoloid dentitions and it could be considered as an important morphological and racial characteristic of the Singaporean Chinese.     

Relationship between sialographic findings of parotid glands and histopathologic finding of labial glands in Sj?gren's syndrome. Relation to clinical and immunologic findings.

We investigated a relationship between sialographic findings of parotid glands and histopathologic changes of labial glands, in relation to Sj?gren's syndrome. We examined 107 patients, suspected to have Sj?gren's syndrome because of dry mouth and dry eyes, in whom no other autoimmune diseases were diagnosed. Parotid sialography identified 37 patients with punctate, globular, cavitary, or destructive sialectasia (S-positive group). These sialographic findings were not seen in the other 70 patients (S-negative group). Among these patients, 54 demonstrated periductal lymphocytic infiltration in the labial glands (H-positive group), whereas the other 53 patients did not demonstrate this histologic finding (H-negative group). Significant differences in stimulated parotid salivary flow rate and incidence of keratoconjunctivitis sicca were observed between patients in the S-positive and the S-negative groups. Differences in the salivary flow rate and the incidence of keratoconjunctivitis sicca were also seen between patients in the H-positive and the H-negative groups, although the differences were not statistically significant. The rate of incidence of serum rheumatoid factor, anti-SS-A, and anti-SS-B antibodies were significantly higher in the S-positive and the H-positive groups than in their negative counterparts.     

Resin-bonded fixed partial dentures: A recall study

A clinical recall program was initiated at the University of Minnesota to evaluate the longevity and factors affecting longevity of resin-bonded fixed partial dentures (FPDs). Of the 49 resin-bonded FPDs evaluated in the clinic, 43 were acid-etched metal, resin-bonded FPDs, four were combinations of resin-bonded and conventional FPDs, and two were composite resin pontics. None of the combination FPDs and one of the two composite resin pontics were judged as failed at the examination. Of the 43 acid-etched metal resin-bonded FPDs, 15 were found to be debonded (failure rate = 34.9%). The average length of service for the 43 FPDs was 47.3 months. The average time of placement to debondment was 33 months for the 15 debonded FPDs. The failure rate for maxillary FPDs and FPDs with two retainers were significantly lower than the failure rate for mandibular FPDs and FPDs with more than two retainers (p greater than 0.05). The clinical significance of the present study was discussed.