Mehmet Akin

Can white spot lesions be treated effectively

OBJECTIVE To compare the effects of sodium fluoride mouth rinse, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and the microabrasion technique in treating white spot lesions. MATERIALS AND METHODS The study population consisted of 80 patients (46 females, 34 males; 966 affected teeth) who had developed multiple decalcified enamel lesions after fixed orthodontic therapy. The study population was divided into four groups of 20 patients each. The control group (group I) participants were to just brush their teeth, the fluoride group (group II) participants were instructed to use 20 ml of neutral 0.025% sodium fluoride rinse, the participants in the CPP-ACP group (group III) were instructed to use tooth mousse twice a day in addition to fluoride toothpaste for 6 months, and the participants in the microabrasion group (group IV) were to undergo treatment by the microabrasion technique, which is a commonly used mixture of 18% hydrochloric acid. Data were analyzed with the generalized linear mixed model and Tukey HSD at the P < .05 level. RESULTS The area of the white spot lesions decreased significantly in all groups. Inter group differences in the treatment success rates were significant. The highest success rate was observed for group IV (97%). The success rate of group III (58%) was significantly higher than that of groups II (48%) and I (45%). CONCLUSIONS The use of CPP-ACP can be more beneficial than fluoride rinse for postorthodontic remineralization. Microabrasion is an effective treatment for cosmetic improvement of long-standing white spot lesions.

Effect of Nd:YAG laser bleaching and antioxidizing agents on the shear bond strength of brackets.

OBJECTIVE The aims of this study were to evaluate the effect of hydrogen peroxide bleaching agents, both nonactivated and activated by a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, and of antioxidant treatment on the shear bond strength (SBS) of orthodontic brackets. BACKGROUND DATA Nd:YAG laser activation is expected to accelerate the bleaching therapy without decrease shear bond strength. MATERIALS AND METHODS Ninety extracted maxillary central incisors were divided into two experimental groups and a control group. Group I was the control group, Group II was bleached with 35% hydrogen peroxide and had no photoactivation, and Group III was bleached with 35% hydrogen peroxide with activation by a Nd:YAG laser (4.0 W, 60 Hz frequency, 1 mm distance, 20 sec). Each group was divided into two subgroups: Subgroup A was immersed in artificial saliva for 2 weeks, and then bonded using the total etch system, whereas subgroup B was treated with an antioxidant agent (10% sodium ascorbate) and then bonded using the same system. The samples were stored in water for 24 h at 37°C, and thermocycled. The SBS in megapascals (MPa) was determined by a shear test with 1 mm/min crosshead speed, and failure types were classified with modified adhesive remnant index scores. The data were analyzed with two way analyses of variance, Tukey, and χ(2) tests at the α = 0.05 level. RESULTS In both Groups II and III, the SBSs of brackets bonded after bleaching (Group II 15.16, Group III 17.50 MPa) were significantly lower than those of brackets in the bonded unbleached group (Group I 22.13 MPa); however, sodium ascorbate treatment significantly increased the SBSs of brackets in the bleached groups (Group II 21.52, Group III 22.43 MPa), but had an insignificant effect on the SBS of the control group (Group I 23.66MPa). CONCLUSIONS Hydrogen peroxide bleaching agents reduce the SBSs both with and without Nd:YAG laser activation; however, treatment of the bleached enamel surface with 10% sodium ascorbate prior to bonding negates the effect.

Long-term stability of dentoalveolar, skeletal, and soft tissue changes after non-extraction treatment with a self-ligating system

Objective To evaluate the long-term effects of self-ligating brackets (SLBs) on transverse dimensions of arches and skeletal and soft tissues and to quantitatively evaluate the treatment outcome after non-extraction treatment with SLBs. Methods The sample consisted of 24 (18 female and six male) subjects, with a mean age of 14.23 ± 2.19 years, who received treatment with the Damon®3 appliances. Complete records including cephalometric radiographs and plaster models were obtained before treatment (T1), immediately after treatment (T2), six months after treatment (T3), and two years (T4) after treatment. Digital study models were generated. Twenty lateral cephalometric, six frontal cephalometric, and eight dental cast measurements were examined. The Peer Assessment Rating index was used to measure the treatment outcome. The Wilcoxon test was applied for statistical analysis of the changes. Results There were significant increases in all transverse dental cast measurements with active treatment. There was some significant relapse in the long term, particularly in maxillary width (p < 0.05). Statistically significant increases were found in nasal (p < 0.001), maxillary base, upper molar, lower intercanine, and antigonial (p < 0.05) widths in T1-T2. Lower incisors were proclined and protruded in T1-T2. Conclusions SLBs correct crowding by mechanisms involving incisor proclination and protrusion and expansion of the dental arches, without induction of clinically significant changes in hard and soft tissues of the face.

Cone-beam computed tomography evaluation of dentoskeletal changes after asymmetric rapid maxillary expansion

INTRODUCTION The aims of this study were to quantitatively evaluate the changes in arch widths and buccolingual inclinations of the posterior teeth after asymmetric rapid maxillary expansion (ARME) and to compare the measurements between the crossbite and the noncrossbite sides with cone-beam computed tomography (CBCT). METHODS From our clinic archives, we selected the CBCT records of 30 patients with unilateral skeletal crossbite (13 boys, 14.2 ± 1.3 years old; 17 girls, 13.8 ± 1.3 years old) who underwent ARME treatment. A modified acrylic bonded rapid maxillary expansion appliance including an occlusal locking mechanism was used in all patients. CBCT records had been taken before ARME treatment and after a 3-month retention period. Fourteen angular and 80 linear measurements were taken for the maxilla and the mandible. Frontally clipped CBCT images were used for the evaluation. Paired sample and independent sample t tests were used for statistical comparisons. RESULTS Comparisons of the before-treatment and after-retention measurements showed that the arch widths and buccolingual inclinations of the posterior teeth increased significantly on the crossbite side of the maxilla and on the noncrossbite side of the mandible (P <0.05). Comparison of the 2 sides showed statistically significant differences in both the maxilla and the mandible (P <0.05). CONCLUSIONS After ARME treatment, the crossbite side of the maxilla and the noncrossbite side of the mandible were more affected than were the opposite sides.

Three-dimensional evaluation of hybrid expander appliances: A pilot study

OBJECTIVE To evaluate transverse dimensional changes in dentoalveolar and skeletal structures caused by hybrid expander, using cone-beam computed tomography (CBCT). MATERIALS AND METHODS The CBCT records of nine patients (five boys and four girls) (mean age 13.61 ± 0.72 years) treated with hybrid expander were examined. CBCT images were taken at pretreatment and after the expansion. ELSA (point equidistant to both foramina spinosa) was determined as a reference point to compare the distances in all three dimensions. Nineteen transversal dimensions and four angles were measured for both right and left sides. Wilcoxon signed rank test was used for statistical comparison at P < .05 levels. RESULTS A V-shaped expansion of suture was successfully achieved in all patients without teeth support. The amount of opening was greater in anterior than posterior and in inferior than superior. An 8.75-mm screw expansion was achieved for all patients. Expansion effects reverberated to maxillary central incisor, canine, first premolar, and first molar at 70%, 75%, 92%, and 89%, respectively. The molar teeth tipped buccally (right 3.06° and left 3.24°) as did premolars (right 2.88° and left 3.02°). CONCLUSION The hybrid expander, minimally invasive expansion appliance that protects teeth by including bone support, can be used easily for rapid maxillary expansion treatment.

Shear-bond-strength of orthodontic brackets to aged nano-hybrid compositeresin surfaces using different surface preparation

The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (p<0.001) between the groups. Sandblasted group had the highest SBS value (12.85 MPa) in experimental groups. The sandblasting surface treatment is recommended as an effective method of bonding orthodontic metal brackets to nano-hybrid composite resin surfaces.

Can demineralized enamel surfaces be bonded safely

Abstract Objective. To evaluate and compare the effects of enamel demineralization, microabrasion therapy and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application on the shear bond strength (SBS) of orthodontic brackets bonded to enamel surfaces and enamel color. Materials and methods. Eighty freshly extracted human maxillary premolar teeth were allocated to one of the four groups. Brackets were bonded directly to non-demineralized enamel surfaces in Group I (control group), directly to the demineralized enamel surfaces in Group II, to demineralized enamel surfaces after CPP-ACP application in Group III and to demineralized enamel surfaces after microabrasion therapy in Group IV. The samples were stored in water for 24 h at 37°C and then underwent thermocycling. The SBS in megapascals (MPa) was determined by a shear test with 0.5 mm/min crosshead speed and failure types were classified with modified adhesive remnant index scores. The data were analyzed with one-way analyses of variance (ANOVA), Tukey and chi-square tests at the α = 0.05 level. Results. Significant differences were found among the four groups (F = 21.57, p < 0.01). No significant difference was found between Group I and III (17.12 ± 2.84 and 15.08 ± 3.42 MPa, respectively) or between Group III and IV (12.82 ± 2.64 MPa). The lowest SBS value was determined in Group II (5.88 ± 2.12 MPa). Enamel demineralization, microabrasion therapy and CPP-ACP application affected enamel color significantly. Conclusion. CPP-ACP application and microabrasion therapy are able to increase the decreased SBS of orthodontic brackets because of enamel demineralization.

Evaluation of Enamel Surface Roughness after Various Finishing Techniques for Debonding of Orthodontic Brackets

Objective The aim of this study was to evaluate the surface roughness of enamel after debonding with various types of burs. Methods The buccal surfaces of 20 mandibular incisors for each group of bur were subjected to profilometer analysis, and three parameters of surface irregularity were recorded. After bracket debonding, adhesive remnants were removed by tungsten carbide burs in low-speed, high-speed, and stainbuster settings. The samples were evaluated at pre-treatment (on sound enamel) (T1) and post-treatment (T2) by a profilometer. The specimens were measured twice, and the mean values were recorded. Results The results were analyzed in intra-group comparisons with paired t-tests and in inter-group comparisons with one-way ANOVA and Tukeys HSD test. All resin removal techniques significantly increased enamel surface roughness (p<0.05). According to one-way ANOVA, there were significant differences in the effect of enamel surface roughness between all methods (p<0.05). The high-speed bur caused the maximum roughness values and the stainbuster bur caused the minimum roughness values in all the parameters (Ra, Rz, and Rq). Conclusion The three types of burs used for finishing methods revealed significant differences in the enamel surface after debonding. However, the stainbuster bur created smoother surfaces than the other applied methods.

Effects of Different Demineralization-Inhibiting Methods on the Shear Bond Strength of Glass-Ceramics

PURPOSE This in vitro study was undertaken to evaluate the effects of different demineralization-inhibiting methods on the shear bond strength (SBS) of glass-ceramics. MATERIALS AND METHODS Ninety extracted intact human mandibular lateral insicors were randomly divided into six equal groups. Group C was left untreated, while enamel subsurface demineralization was induced in the other groups. In group D, porcelain discs (3 mm in diameter) were cemented to demineralized enamel by using total-etch photopolymerizing luting composite resin without pretreatment. Demineralized specimens in groups F, CA, M, and I were pretreated with fluoride gel, CPP-ACP paste, microabrasion, and resin infiltration, respectively, and then porcelain discs were cemented. SBS (MPa) was calculated from the failure load (N) per bonded area (mm(2)). Fracture types were examined by optical microscopy (40× magnification). Data were analyzed with ANOVA, Tukeys test, and G-test. RESULTS ANOVA revealed significant intergroup differences (p < 0.01). No significant differences in SBS (MPa) were found between groups C (19.48 ± 2.0) and I (20.02 ± 1.6). Lower SBS values were recorded in groups D (7.93 ± 0.8), F (12.51 ± 1.5), CA (17.08 ± 1.3), and M (14.84 ± 1.4). Mixed and cohesive failures were the most prevalent in groups M and I, respectively. CONCLUSION Resin infiltration enhanced the SBS of porcelain discs bonded to demineralized enamel when compared with the other demineralization-inhibiting methods. CLINICAL RELEVANCE Resin infiltration could be useful to enhance adhesion of glass-ceramics to teeth with white spot lesions.

Adhesion of metal brackets to glassy matrix and hybrid CAD/CAM materials after different physico-chemical surface conditioning

Abstract This study compared the adhesion of metal brackets bonded to different CAD/CAM materials after various surface conditioning methods. CAD/CAM blocks (N = 204, n = 17 per group) of (a) VITA Mark II (VM), (b) IPS e.max CAD (IP), (c) Lava Ultimate (LU), and (d) VITA ENAMIC (VE) were conditioned with one of the following methods: C-Control: (fine diamond bur); CJ: (fine diamond bur + air-abrasion with 30 μm SiO2 + silane), and HF: (fine diamond bur +9.5% hydrofluoric acid + silane). Metal brackets were bonded to the conditioned surfaces of the specimens, stored in artificial saliva for 24 h at 37 °C and thermocycled (×1000). Subsequently, the brackets were debonded under shear in a Universal Testing Machine (1 mm/min). Failure types were analyzed under scanning electron microscope. Data were analyzed using two-way ANOVA and Tukey’s tests (α = 0.05). Two-parameter Weibull distribution values, including the Weibull modulus, scale, and shape, were calculated. Mean bond strength (MPa) values were significantly affected by the surface conditioning method (p < 0.001) but not the CAD/CAM material type (p = 0.052). Bond strengths for all CJ and HF-conditioned specimens were twofold higher (11.83 ± 1.95 − 9.44 ± 1.63) than those for control specimens with all materials (4.73 ± 0.93 − 6.02 ± 0.69). Lower mean values were obtained in LU-CJ (9.78 ± 1.61) and LU-HF (9.44 ± 1.63) than those for other groups (11.83 ± 1.95 − 10.93 ± 1.33) groups (p < 0.05). Weibull distribution showed higher shape values for VM-CJ (11.26) and VM-HF (8.87) than those for other groups (0.82–1.83). In control groups, exclusively adhesive and after conditioning mainly mixed failures were observed. Chairside silica coating or HF conditioning significantly improved metal bracket adhesion to both glassy matrix and hybrid CAD/CAM materials tested, with the most reliable adhesion being observed for feldspathic ceramic.