Effects of sealant and self-etching primer on enamel decalcification. Part I: an in-vitro study.

INTRODUCTION: The objective of this study was to compare the resistance to enamel demineralization between self-etching primer (SEP) and conventional sealant in vitro. METHODS: A total of 120 molar sections were randomly assigned to 3 groups: SEP (Transbond Plus, 3M Unitek, Monrovia, Calif), sealant (Light Bond fluoride-releasing sealant, Reliance Orthodontic Products, Itasca, Ill), or control (no enamel treatment). SEP or sealant was applied following the manufacturer's recommendations. The tooth samples were exposed to rotary brushing for 2 minutes. A 2 x 2-mm window of sound enamel was created by using nail varnish. After 48 or 72 hours of acidic challenge with Ten Cate solution (pH 4.46), the samples were sectioned down to a thickness of 200 microm and stained with rhodomine B dye to evaluate lesions, lesion depths, area of lesions, and total fluorescence by using confocal microscopy. Statistical analyses were performed with 1-way analysis of variance (ANOVA) and Tukey-Kramer tests. RESULTS: The incidence of lesion was 50% in the sealant group and 100% in both the SEP and the control group. The lesion in the sealant group was present only when the sealant integrity was broken. Lesion depth (149.9 +/- 20.5 microm), area (636 +/- 90 x 10(2) microm(2)), and total fluorescence (252 +/- 83 x 10(4)) in the SEP group were similar to those in the controls. Lesion depth (107.6 +/- 45 microm), area (441 +/- 212 x 10(2) microm(2)), and fluorescence (160 +/- 103 x 10(4)) in the sealant group were significantly less than in the SEP and control groups (P <0.05). CONCLUSIONS: These results suggest that neither sealant completely protects the teeth against enamel decalcification. The application of sealant provided protection in 50% of the samples, whereas the SEP provided no resistance to enamel demineralization. Protection from acid demineralization depends on the integrity of the sealant.

Oral health disparities in Appalachia: orthodontic treatment need and demand.

BACKGROUND: Significant oral health disparities affect people in West Virginia and elsewhere in Appalachia. Although oral diseases such as caries are a major problem, little is known about the occlusal status of this under-served group. METHODS: Fifty-eight adolescents (ages 12-17 years) and 78 of their parents underwent an orthodontic examination as part of a larger study on oral health in two rural West Virginia counties. Two orthodontists used a standardized index to rate their need for orthodontic care. Participants were interviewed regarding their demand for and history of orthodontic care. RESULTS: The study results show that parents had a high rate of complete or partial edentulism, an infrequent history of orthodontic treatment, great unmet orthodontic need and less demand for orthodontic care than was suggested by their clinically determined need. The adolescents were similar to national norms with regard to orthodontic treatment history and need, but lower with regard to demand. CONCLUSIONS: The adolescents' similarity to general population norms with regard to previous orthodontic care and level of occlusal status is promising. Nevertheless, their lower recognition of a need for treatment suggests possible future oral health problems and a lower oral health quality of life. Their parents, however, were considerably worse off, in comparison with their adolescent children and adult comparison samples, with regard to orthodontic care and other oral health status measures. CLINICAL IMPLICATIONS: Culturally sensitive psychoeducational methods to promote recognition of oral health needs may be required among adolescents in Appalachia to have an impact on oral health values and to prevent oral health problems. Issues of orthodontic care utilization and, perhaps, access to care need to be addressed among adults in Appalachia.

Comparison of bond strength between orthodontic brackets bonded with halogen and plasma arc curing lights: an in-vitro and in-vivo study.

INTRODUCTION: This study assessed in-vitro shear bond strength and in-vivo survival rate of orthodontic brackets bonded with either a halogen or a plasma arc light. METHODS: Ninety extracted premolars were divided into 6 groups of 15. Stainless steel brackets were bonded to the teeth by using either a halogen light with a 20-second curing time or a plasma arc light with a 2-, 6-, or 10-second curing time. Brackets were debonded either within 30 minutes of bonding or after thermocycling for 24 hours. Bond strengths were tested on a testing machine at a crosshead speed of 1 mm/minute. The bracket failure interface was measured with a modified adhesive remnant index score. Data were analyzed by using ANOVA and Tukey-Kramer multiple comparison tests. For the in-vivo study, a split-arch design was used to determine the bracket-failure rate and distribution in 25 patients. The patients were followed for a mean period of 1.1 years (386 days). Survival analysis was carried out to compare the failure rates of the 2 techniques. RESULTS: No significant differences in bond strengths were found 30 minutes after bonding between the halogen light (13.6 +/- 3.8 MPa) and the plasma arc light with 2-, 6-, or 10-second curing times (9.6 +/- 2.9, 14.2 +/- 4.6, 16.0 +/- 3.0 MPa, respectively). Similar bond strengths were also found between the halogen light with a 20-second (16.1 +/- 3.6 MPa) curing time and plasma arc light with 6 seconds (18.2 +/- 4.6 MPa) of curing time after 24 hours of thermocycling. For the in-vivo study, no significant difference was found in bracket failure rates between the 2 light sources (4.9% in both groups). No significant differences were found between ARI scores for the halogen light and the plasma arc light at either 30 minutes or 24 hours after debonding. CONCLUSIONS: These results indicate that the plasma arc light with a 6-second curing time can produce similar bond strength and bracket-failure rates as the halogen light that requires a longer curing time.

Guidance of eruption for general practitioners.

The principle of early treatment through well-planned extraction of primary teeth followed by removal of permanent teeth has stood the test of time. The objective of this article is to develop some simple guidelines for general dental practitioners to perform 'guidance of eruption' in malocclusion with severe crowding.