Effect of topical fluoride application and diode laser-irradiation on white spot lesions of human enamel.

OBJECTIVES: This study aims to evaluate the effectiveness of topical fluoride application and diode laser-irradiation on the hardness of demineralized enamel and to evaluate the esthetic improvement of the white spot lesions (WSLs) using a visual analog scale (VAS). MATERIALS AND METHODS: Artificial WSLs (3x3 mm) were created on the enamel surface of 45 human third molars. The teeth were randomly assigned into three groups (n = 15): group A, fluoride only; group B, combined therapy of fluoride and diode laser; and group C, control. Vicker's hardness number (VHN) was measured at baseline, after demineralization and after treatment. To evaluate the esthetic improvement after treatment, 14 raters evaluated each group's photographs using a 100-millimeter VAS. A one-way ANOVA or Brown-Forsythe and Games-Howell post hoc procedure were performed for statistical analysis. The level of significance was set at α = 0.05 for all tests. RESULTS: Group A mean VHN was significantly higher than groups B and C, and group B was significantly higher than group C (P < 0.05). However, the mean VAS rating for the combined therapy group (B) was significantly higher than that for groups A and C (P < 0.05). CONCLUSION: Combination therapy significantly improved the esthetic appearance of WSLs compared to the fluoride only group. However, there was less enamel hardness versus treatment with fluoride only.

Effect of diode laser and topical fluoride applications on white-spot lesions in bovine enamel.

This study evaluated the effectiveness of diode laser irradiation combined with topical fluoride application for increasing the hardness of demineralized bovine enamel and esthetically improving white-spot lesions (WSLs). In addition, the study evaluated intrapulpal temperature changes during laser irradiation. One hundred twenty bovine incisors with 4 × 4-mm artificial WSLs were randomly assigned to 8 groups (n = 15): untreated control; fluoride only; LF1, LF2, and LF3, fluoride plus 2-W laser for 15, 30, and 60 seconds, respectively; and LF4, LF5, and LF6, fluoride plus 5-W laser for 15, 30, and 60 seconds, respectively. The Vickers hardness number, CIE L*a*b color space values, and visual analog scale ratings for color improvement were recorded at baseline, after demineralization to create the WSLs, and after treatment. The intrapulpal temperature changes were recorded at completion of irradiation for 30 bovine teeth that were assigned to 6 groups (n = 5) to receive doses of irradiation equivalent to the treatment of the corresponding laser groups described previously. Statistical analysis included 1-way analysis of variance and Tukey multiple comparison tests (α = 0.05) The mean Vickers hardness numbers were significantly greater for the laser groups, and mean visual analog scale scores were significantly greater for all the treatment groups (P < 0.05). The fluoride group had a significantly lower mean color change (ΔE*) value (P < 0.05). The mean intrapulpal temperature changes in the 5-W laser groups were significantly greater than those in the 2-W groups (P < 0.05). Diode laser irradiation combined with topical fluoride application significantly increased the hardness and improved the esthetic appearance of WSLs compared to no treatment (control) and fluoride treatment alone. Intrapulpal temperature changes indicated that diode laser irradiation is safer at a 2-W setting than a 5-W setting.

Molecular Analysis of Congenital Hypothyroidism in Saudi Arabia: SLC26A7 Mutation Is a Novel Defect in Thyroid Dyshormonogenesis.

Context: Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder, affecting one in 3000 to 4000 newborns. Since the introduction of a newborn screening program in 1988, more than 300 cases have been identified. The underlying genetic defects have not been systematically studied. Objective: To identify the mutation spectrum of CH-causing genes. Methods: Fifty-five patients from 47 families were studied by next-generation exome sequencing. Results: Mutations were identified in 52.7% of patients (29 of 55) in the following 11 genes: TG, TPO, DUOX2, SLC26A4, SLC26A7, TSHB, TSHR, NKX2-1, PAX8, CDCA8, and HOXB3. Among 30 patients with thyroid dyshormonogenesis, biallelic TG mutations were found in 12 patients (40%), followed by biallelic mutations in TPO (6.7%), SLC26A7 (6.7%), and DUOX2 (3.3%). Monoallelic SLC26A4 mutations were found in two patients, one of them coexisting with two tandem biallelic deletions in SLC26A7. In 25 patients with thyroid dysgenesis, biallelic mutations in TSHR were found in six patients (24%). Biallelic mutations in TSHB, PAX 8, NKX2-1, or HOXB3 were found once in four different patients. A monoallelic CDCA8 mutation was found in one patient. Most mutations were novel, including three TG, two TSHR, and one each in DUOX2, TPO, SLC26A7, TSHB, NKX2-1, PAX8, CDCA8, and HOXB3. SLC26A7 and HOXB3 were novel genes associated with thyroid dyshormonogenesis and dysgenesis, respectively. Conclusions: TG and TSHR mutations are the most common genetic defects in Saudi patients with CH. The prevalence of other disease-causing mutations is low, reflecting the consanguineous nature of the population. SLC26A7 mutations appear to be associated with thyroid dyshormonogenesis.

A Novel Mutation in the CYP11B1 Gene Causes Steroid 11ß-Hydroxylase Deficient Congenital Adrenal Hyperplasia with Reversible Cardiomyopathy.

Congenital adrenal hyperplasia (CAH) due to steroid 11ß-hydroxylase deficiency is the second most common form of CAH, resulting from a mutation in the CYP11B1 gene. Steroid 11ß-hydroxylase deficiency results in excessive mineralcorticoids and androgen production leading to hypertension, precocious puberty with acne, enlarged penis, and hyperpigmentation of scrotum of genetically male infants. In the present study, we reported 3 male cases from a Saudi family who presented with penile enlargement, progressive darkness of skin, hypertension, and cardiomyopathy. The elder patient died due to heart failure and his younger brothers were treated with hydrocortisone and antihypertensive medications. Six months following treatment, cardiomyopathy disappeared with normal blood pressure and improvement in the skin pigmentation. The underlying molecular defect was investigated by PCR-sequencing analysis of all coding exons and intron-exon boundary of the CYP11B1 gene. A novel biallelic mutation c.780 G>A in exon 4 of the CYP11B1 gene was found in the patients. The mutation created a premature stop codon at amino acid 260 (p.W260 (∗) ), resulting in a truncated protein devoid of 11ß-hydroxylase activity. Interestingly, a somatic mutation at the same codon (c.779 G>A, p.W260 (∗) ) was reported in a patient with papillary thyroid cancer (COSMIC database). In conclusion, we have identified a novel nonsense mutation in the CYP11B1 gene that causes classic steroid 11ß-hydroxylase deficient CAH. Cardiomyopathy and cardiac failure can be reversed by early diagnosis and treatment.

Is arch form influenced by sagittal molar relationship or Bolton tooth-size discrepancy?

BACKGROUND: Orthodontic patients show high prevalence of tooth-size discrepancy. This study investigates the possible association between arch form, clinically significant tooth-size discrepancy, and sagittal molar relationship. METHODS: Pretreatment orthodontic casts of 230 Saudi patients were classified into one of three arch form types (tapered, ovoid, and square) using digitally scanned images of the mandibular arches. Bolton ratio was calculated, sagittal molar relationship was defined according to Angle classification, and correlations were analyzed using ANOVA, chi-square, and t-tests. RESULTS: No single arch form was significantly more common than the others. Furthermore, no association was observed between the presence of significant Bolton discrepancy and the sagittal molar relationship or arch form. Overall Bolton discrepancy is significantly more prevalent in males. CONCLUSIONS: Arch form in a Saudi patient group is independent of gender, sagittal molar relationship, and Bolton discrepancy.