Comparison of the intrusive effects of miniscrews and utility arches.

INTRODUCTION: The aim of this prospective study was to compare the effects of incisor intrusion obtained with the aid of miniscrews and utility arches. METHODS: Twenty-four patients (10 male, 14 female) with a deepbite of at least 4 mm were divided to 2 groups. In group 1, 13 patients (3 male, 10 female; mean age, 20.90 ± 7.12 years) in the postpubertal growth period were treated by using miniscrews; in group 2, 11 patients (7 male, 4 female; mean age, 15.25 ± 3.93 years) were treated with utility arches. Lateral cephalometric headfilms were taken at the beginning of treatment and after intrusion for the evaluation of the treatment changes. Statistical analyses of the data were performed with a significance level of P <0.05. RESULTS: Intrusion lasted 6.61 ± 2.95 months for group 1 and 6.61 ± 2.46 months for group 2. The changes in the center of resistance of the incisors were 1.75 ± 0.4 mm (P <0.05) for group 1 and 0.86 ± 0.5 mm (P >0.05) for group 2; the difference between the groups was significant (P <0.05). In the miniscrew group, the incisors were protruded 0.79 ± 1.4 mm (P >0.05) relative to pterygoid vertical and 3.85° ± 2.4° (P >0.05) relative to the palatal plane. In group 2, the incisors showed 3.91 ± 0.7 mm (P <0.05) of protrusion relative to pterygoid vertical and 13.55° ± 2.4° (P <0.05) relative to the palatal plane. The maxillary first molars showed significant distal tipping in group 2 (P <0.05). CONCLUSIONS: Unlike with utility arches, true maxillary incisor intrusion can be achieved by application of intrusive forces close to the center of resistance by using miniscrews with no counteractive movements in the molars.

The effects of prophylactic ozone pretreatment of enamel on shear bond strength of orthodontic brackets bonded with total or self-etch adhesive systems.

OBJECTIVES: The aim of this in vitro study is to determine (1) shear bond strength (SBS) of brackets bonded with self-etch and total-etch adhesive after ozone treatment (2) bond failure interface using a modified Adhesive Remnant Index (ARI). METHODS: 52 premolars were randomly assigned into four groups (n=13) and received the following treatments: Group 1: 30 s Ozone (Biozonix, Ozonytron, Vehos Medikal, Ankara, Turkey) application + Transbond Plus Self-Etching Primer (SEP) (3M) + Transbond XT (3M), Group 2: Transbond Plus SEP + Transbond XT, Group 3: 30 s Ozone application + 37% orthophosphoric acid + Transbond XT Primer (3M) + Transbond XT, Group 4: 37% orthophosphoric acid + Transbond XT Primer + Transbond XT. All samples were stored in deionised water at 37°C for 24 hours. Shear debonding test was performed by applying a vertical force to the base of the bracket at a cross-head speed of 1 mm/min. RESULTS: The mean SBS results were Group 1: 10.48 MPa; Group 2: 8.89 MPa; Group 3: 9.41 MPa; Group 4: 9.82 MPa. One-Way Variance Test revealed that the difference between the groups was not statistically significant (P=0.267). Debonded brackets were examined by an optical microscope at X16 magnification to determine the bond failure interface using a modified ARI. The results were (mean) Group 1: 2.38; Group 2: 1.31; Group 3: 3.00; Group 4: 1.92. Multiple comparisons showed that Groups 1 and 2, 2 and 3, 3 and 4 were statistically different (P=0.014, P<.001 and P=0.025). CONCLUSIONS: Ozone treatment prior to bracket bonding does not affect the shear bond strength.

Maxillomandibular fixation screws for early removal of hardware and correction of lingual tilting in alveolar distraction osteogenesis.

Alveolar distraction osteogenesis is a well-known technique used for the management of deficient alveolar ridges. Vector control of the transport segment is the main problem during distraction. This article describes a new technique for early removal of distractor and correction of tilted transport segment in partially edentulous patients.

Effects of the zygoma anchorage system on canine retraction.

The aim of this study was to compare the effects of the Gjessing (PG) retraction spring used with and without the zygoma anchorage system (ZAS) on canine retraction. Thirty patients, with an Angle Class I or Class II malocclusion, whose upper first premolars were scheduled for extraction, were divided into two equal groups. Group 1 comprised maximum anchorage cases (nine females and six males with a mean age of 16 years 8 months) in which the ZAS was used to improve posterior anchorage and the PG retraction springs for canine retraction. Moderate anchorage cases (10 females and 5 males with a mean age of 15 years 5 month) were included in group 2 and canine retraction was achieved using only PG retraction springs. Study models and lateral cephalometric radiographs obtained at the initial and final stages of canine retraction were used for comparison of the groups to determine the effects of zygoma anchorage on canine retraction. All measurements were evaluated statistically using a Student's t-test, 2 × 2 repeated measures analysis of variance, Bonferroni-adjusted t-test, and Mann-Whitney U and Wilcoxon tests according to the normality of the distribution of the variables. Mesial crown movement of the molars was 0.63 mm (P < 0.05) in group 1 and 1.50 mm (P < 0.001) in group 2. There was a statistically significant difference (P < 0.05) between the groups. No significant difference was observed between the groups for the rate of canine retraction or sagittal and vertical movement of the canines. The ZAS is a reliable and successful anchorage reinforcement method for canine retraction in extraction cases.

Repositioning of the masseter muscle and its effect on skeletal growth.

OBJECTIVE: The aim of this study was to establish a model to aid in understanding the influences of bilateral masseter muscle relocation on the bone and muscle, and to determine the influences of bilateral masseter muscle relocation on mandibular growth pattern in rabbits. STUDY DESIGN: Ten 3-month-old growing white New Zealand rabbits were included. Digital lateral cephalometric radiographs were obtained before operation and 6 months after surgery. The Co-Gn, gonial angle, FMA, ANS-Me, GoGn-SN, Y-axis, and Jarabak values were compared by using Student t test. RESULTS: There was a statistically significant difference between the groups in the gonial angle (P < .05). Vertical height values (GoGn-SN, FMA, Y-axis, and ANS-Me) showed statistically significant increases in animals in the control group. In contrast, vertical height values in the experimental group did not show statistically significant increase. CONCLUSIONS: Anterior relocation of the masseteric muscle influenced the direction of vertical growth significantly compared with the control group.

Success of zygomatic plate-screw anchorage system.

PURPOSE: To evaluate the success of zygomatic plate-screw anchorage and to define the key points that help to improve the success of this system. MATERIALS AND METHODS: A total of 74 zygomatic plate-screw anchors were applied to 37 patients from 2 groups receiving orthodontic treatment. The first group consisted of 19 patients, and the zygoma anchors were applied bilaterally to distalize the maxillary buccal segment. The second group consisted of 18 patients, and the zygoma anchors were applied bilaterally to stabilize the maxillary molars during maxillary canine retraction. The orthodontic force was applied 1 week after the insertion of the plates. In the first group, 450 g of direct force and in the second group 150 g of indirect force were applied to the zygomatic plates. The success rate of the zygomatic plate-screw anchorage system was evaluated. RESULTS: One plate was lost and the others remained stable all through the orthodontic treatment. Mild gingival inflammation was observed in 1 patient (2 plates), and pus formation was detected in 1 patient (2 plates). One plate was covered because of mucosal hypertrophy. CONCLUSION: Zygomatic plate-screw anchorage system is a reliable technique to obtain orthodontic anchorage and may eliminate the need for extraoral force. However, the surgical insertion technique, position of the plates, and oral hygiene status of the patients certainly influence the success of the system.

Qualitative and quantitative evaluation of enamel after various stripping methods.

INTRODUCTION: In this study, we investigated ultramorphology, surface roughness, and microhardness of permanent and deciduous tooth enamel after various stripping methods. METHODS: One hundred twenty deciduous and permanent teeth (n = 60 each) were used. Qualitative (scanning electron microscopy) and quantitative (surface roughness and microhardness tests) experiments were carried out in the following experimental groups: group 1, stripping disk; group 2, diamond-coated metal strip; group 3, stripping disk and Sof-Lex discs (3M-ESPE, Seefeld, Germany); group 4, diamond-coated metal strip and Sof-Lex discs; group 5 (chemical stripping), 37% orthophosphoric acid in conjunction with diamond-coated metal strip; group 6 (control), no stripping. Surface roughness values (Ra) for permanent and deciduous enamel were evaluated with Welch analysis of variance (ANOVA) and Tamhane tests, and Kruskal-Wallis and Mann-Whitney tests, respectively. Microhardness values were evaluated statistically with Kruskal-Wallis, 1-way ANOVA, and Duncan tests. RESULTS: Deciduous and permanent teeth showed similar results in terms of surface roughness and surface morphology. Groups 3 and 4 had the smoothest deciduous and permanent enamel surfaces, whereas chemical stripping (group 5) produced the roughest surfaces in both enamel types. Stripping did not lead to a significant change in the microhardness of permanent enamel. CONCLUSIONS: All stripping methods significantly roughened the enamel surfaces. Polishing the stripped surface with Sof-Lex discs decreased the roughness.

Effect of resin-removal methods on enamel and shear bond strength of rebonded brackets.

The objective of this study is to determine (1) the effect of different resin-removal methods on shear bond strength (SBS) of rebonded brackets, (2) condition of the enamel surface, (3) time spent to remove resin remnants, and (4) the location of the bond failure. A total of 80 premolars were included in the study. Fifty of them were divided into five groups and bonded using Light Bondtrade mark sealant and Quick Curetrade mark adhesive. Ten of the samples were debonded, and the SBS of the first debonding was calculated. Forty brackets were debonded using pliers and examined by an optical microscope (16x) to determine the location of the bond failure interface, using a modified Adhesive Remnant Index (ARI). The remnant adhesives were cleaned with four methods: (1) low-speed tungsten-carbide bur (TCB), (2) high-speed TCB, (3) Sof-Lex finishing disks, and (4) microetcher. The brackets were rebonded, and a second set of SBS and ARI values were calculated and statistically evaluated. Thirty of the premolars were divided into five groups receiving the same resin-removal methods and examined by scanning electron microscope. Rebonded teeth had a greater SBS than the initial bonding, except in group 4. The rebonded SBS values were similar in groups 1-3, and only group 4 showed a statistical difference. Sof-lex discs were the most time-consuming procedures and left much adhesive remnant. The high-speed TCB was found to be the most hazardous to the enamel. The scarring of enamel after the debonding is inevitable but can be reduced.