Incidence of dental anxiety in young adults in relation to dental treatment experience

OBJECTIVES: To document the incidence of dental anxiety among individuals aged 18 years at baseline and 26 years at follow-up, and to determine if dental treatment experience continues to play a significant etiological role with respect to the onset of dental anxiety in young adults. METHODS: Dental anxiety scale (DAS; Corah, 1969) scores at ages 15, 18 and 26 were obtained for Study members in the Dunedin Multidisciplinary Health and Development Study. Dental examinations were conducted, and sociodemographic and dental service-use data were collected using a self-report questionnaire. Using a case definition of a DAS score of 13 or more, age 18-26 incident cases were identified and their dental treatment experience and service-use characteristics compared with the remainder. RESULTS: DAS scores at 18 and 26 were available for 792 (80.8%) of the 980 26-year-old Study members. An increase in dental anxiety prevalence was observed over the eight-year period, with an annualized incidence of 2.1%. Fewer incident cases had visited a dentist in the previous eight years, and there were no differences between incident cases and others in their eight-year DFS, FS or tooth-loss increments. A subgroup of "recurrent" cases was identified who were dentally anxious at 15 and 26 but not at 18, and their eight-year incidence of tooth loss due to caries was substantially higher than non-cases. CONCLUSIONS: Aversive conditioning experiences appear to be unrelated to the adult onset of dental anxiety, and it may be that particular temperamental or psychological traits are associated with the condition.     

Diversity of oral asaccharolytic Eubacterium species in periodontitis--identification of novel phylotypes representing uncultivated taxa

Oral asaccharolytic Eubacterium species are associated with periodontal disease and other oral infections. The aim of this study was to use a culture-independent molecular technique to determine the diversity of asaccharolytic Eubacterium species in subgingival plaque in periodontitis. An oligonucleotide PCR primer designed to amplify 16S rRNA genes of the oral asaccharolytic Eubacterium branch of the phylogenetic tree was constructed. This primer was used together with a universal primer in PCRs to amplify gene sequences directly from a single subgingival plaque sample. Fifty PCR products were purified by cloning, fully sequenced and subjected to molecular phylogenetic analysis. The sequences were assigned to four groups within a single lineage of the low G + C gram-positive bacteria. Group I (58% of the cloned sequences) was assigned to a branch that included Eubacterium nodatum, and Group II (22%) to a branch including Eubacterium infirmum. Group III (8%) was distinct from but related to E. infirmum at the species level, and Group IV (12%) was another novel taxon more distantly related to E. infirmum and E. nodatum.     

Mechanical response to functional loading around the threads of retromolar endosseous implants utilized for orthodontic anchorage: coordinated histomorphometric and finite element analysis

A 3-dimensional bone-implant finite element model was created. The objective was to further investigate the mechanical environment of cortical bone adjacent to the threads of a retromolar endosseous implant used for orthodontic anchorage to mesially translate mandibular molars in response to normal functional loading. This study emphasizes the stress invariants around and between the threads of the implant for future comparison to histomorphometric data from an ongoing clinical study. A strong stress pattern change was found immediately around the implant, which was reflected by a moderate change of stresses between the threads and a significant increase in stress at the tips of the threads.     

Adhesive solutions: report of a case using multiple adhesive techniques in the management of enamel hypoplasia

Enamel hypoplasia is a common condition that may present a severe aesthetic problem. Although the teeth affected may not be particularly susceptible to caries, patients may request cosmetic improvement. Adhesive techniques may be useful in such situations. This paper discusses the management of a patient with enamel hypoplasia using a combination of adhesive systems including enamel- and dentine-bonded veneers, dentine-bonded crowns, a cantilever resin-retained bridge, bonded amalgam restorations and chairside tin plating. Where adhesion was contraindicated, conventionally retained crowns were used.     

Delayed root canal therapy: an analysis of treatment over time.

A retrospective study of 898 teeth receiving root canal therapy was performed to document the sequelae of delayed completion of root canal treatment. Teeth were categorized into a prompt treatment group and a delayed treatment group. Comparisons of prompt and delayed treatment groups were made with regard to preoperative pain, interappointment emergencies, postobturation pain, and final treatment. Findings from this study show that a palliative endodontic procedure is an extremely effective treatment. However, 56% of teeth with incomplete root canal therapy eventually were extracted compared with 2 to 3% for the root canal filling treatment groups. By emphasizing the potential loss of the tooth rather than the potential of interappointment emergencies, the clinician may be more effective in achieving compliance among patients receiving delayed treatment.     

Immunohistological localization of cell adhesion proteins and integrins in the periodontium.

The distribution of the cell adhesion proteins vitronectin, fibronectin, tenascin, and laminin as well as several integrin subunits, alpha 2, alpha 5, and alpha v, was studied in primate periodontal tissues. Full baboon mandibular sections were analyzed by immunohistochemical methods in order to localize the molecules studied in both soft and hard tissues. Vitronectin was associated with the connective tissue of the marginal gingiva, the periodontal ligament, as well as the endosteum and periosteum. A notable finding was the particularly high staining intensity of vitronectin in the periodontal ligament. Fibronectin was widely distributed in the periodontal connective tissue and was also localized to the pericellular matrix of osteocytes and blood vascular elements. Epithelial basement membranes stained positively for both fibronectin and tenascin. These proteins were also expressed in the periosteal and endosteal connective tissues and the periodontal ligament. The staining intensity for tenascin was higher in zones along the cementum and bone surfaces. Laminin was, characteristically, limited to basement membranes of epithelium and endothelium. The distribution of fibronectin, tenascin, and laminin is related to previous findings in other species. The localization of the several integrin alpha-subunits is also described in full baboon mandibular sections. The vitronectin receptor (alpha v) had a uniquely strong expression in osteoclasts of the alveolar bone and was found, at lesser intensity, on periodontal ligament fibroblasts. The fibronectin receptor alpha subunit, alpha 5, was also observed on osteoclasts, and, in addition, was widely distributed on fibroblasts, cementoblasts, and osteoblasts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Polyvinyl siloxane impression materials: a review of properties and techniques.

Polyvinyl siloxane impression materials have been shown to have excellent properties as impression materials; however, they are sensitive to manipulative variables. Several methods of using very high viscosity (putty) materials to form "trays" to obtain uniform bulk of the wash impression are described, and the disadvantages of each of these techniques is pointed out. It is recommended that for best results acrylic resin custom trays should be used routinely. The interaction of polyvinyl siloxane materials with latex products is also discussed and problems that this inhibition can cause are stated. Suggestions to avoid this interaction are outlined. One of the disadvantages of the impression materials is that it has a relatively short working time. Refrigerating the material will increase working time without affecting accuracy.     

The effect of chewing gum use on in situ enamel lesion remineralization.

Two independent cross-over studies investigated the possibility of enhanced early enamel lesion remineralization with the use of chewing gum. The first study involved a sorbitol-containing chewing gum, and the second, which had an identical protocol, tested a sucrose-containing chewing gum. In each study, 12 volunteers wore in situ appliances on which were mounted enamel sections containing artificial caries lesions. Subjects brushed twice daily for two min with a 1100-ppm-F (NaF) dentifrice (control and test) and in the test phase chewed five sticks of gum per day for 20 min after meals and snacks. Microradiographs of the enamel lesions were made at baseline and at the end of the seven-week experimental period. In the sugar-free gum study, the weighted mean total mineral loss (delta z) difference [(wk7-wk0) x (-1)] was 788 vol.% min. x micron for the gum, corresponding to remineralization of 18.2%, vs. the control value of 526 vol.% min. x micron, 12.1% remineralization (p = 0.07). There were no significant differences for the surface-zone (p = 0.20) and lesion-body (p = 0.28) values. In the sucrose-containing gum study, the delta z difference was 743 vol.% min. x micron for the gum, corresponding to a remineralization of 18.3%, vs. the control value of 438 vol.% min. x micron, 10.8% remineralization (p = 0.08). The surface-zone values were not significantly different (p = 0.55). For the lesion body, however, the sucrose-containing gum value of 6.11 vol.% min. was significantly different (p = 0.01) from that of the control (2.81 vol.% min.).     

Maxillary ameloblastoma. Case report and review of the literature

A case of maxillary ameloblastoma is presented. A non-healing, asymptomatic ulcerative lesion in the maxillary tuberosity region did not respond following relief of physical irritation. The clinical appearance of the lesion was compatible with that of a malignant tumour, but the histopathology was consistent with a diagnosis of ameloblastoma of the maxilla.     

Physical examination of caffeine's effects on the enamel surface of first molar in new-born rats.

Samples of the first molars of offspring whose dams were fed a diet supplemented with caffeine were examined by scanning electron microscopy, X-ray diffractometry and electron microprobe analysis. Scanning microscopy of the enamel surface of the caffeine group revealed a consistently rougher surface than in the non-caffeine controls, both before and after acid exposure. X-ray diffraction analysis of the pulverized whole tooth in the caffeine group showed broader diffraction peaks for the lattice plane reflections (202) and (300), indicating smaller crystallites. Pure enamel samples of the caffeine group examined with a Gandolfi X-ray camera also revealed more diffuse diffraction lines than in the non-caffeine controls, further indicating smaller crystallites in the enamel. The calcium and phosphorus contents of the acid-exposed samples in both control and caffeine groups were lower than the non-acid exposed control and caffeine groups by electron microprobe analysis. After exposure to acid, the calcium and phosphorus contents of the outer surface of the enamel in the caffeine group were greatly reduced as compared to that of the non-caffeine controls. Thus various methods consistently indicate that caffeine ingestion during early growth affects the enamel surface of the first molars, resulting in impaired mineralization. Caffeine intake may therefore have a negative effect on amelogenesis and possibly increases susceptibility to dental caries.