A new type of modified Essix Retainer for anterior open bite retention.

The most problematic malocclusion type to retain is anterior open bite although many classical retention appliances are known. The difficulty of maintaining the occlusion arises from the lack of control over the tongue behavior and posture in open bite cases. In the current article, a 2 year follow-up of 2 open-bite patients who were retained with a new type of retention appliance, successfully, were presented.

Effects of sandblasting and silica coating on the bond strength of rebonded mechanically retentive ceramic brackets.

INTRODUCTION: The aim of this study was to determine the bond strength of rebonded mechanically retentive ceramic brackets after treatment with 2 abrasive techniques. METHODS: In addition to a group of new brackets, 3 groups were treated according to the following conditions of debonded ceramic bracket bases: sandblasting, sandblasting + silane, and silica coating + silane (15 in each group). Treated ceramic brackets were rebonded on premolars. The samples were stored in distilled deionized water for 24 hours at 37 degrees C in an incubator and then thermocycled for 1000 times between 5 degrees C and 55 degrees C. Shear force was applied to the enamel-adhesive interface until debonding. RESULTS: The highest bond strength values were in the silica coating + silane and the new bracket groups (12.7 and 12.0 MPa, respectively), followed by the sandblasting + silane group (10.5 MPa). The sandblasting group had a significantly lower bond strength value (4.5 MPa). No enamel fracture was noted in any sample tested. In the new bracket and the sandblasting + silane groups, 20% of the samples had adhesive remnant index scores of 2, and 80% had scores of 3. In the sandblasting group, all specimens debonded at the bracket-adhesive interface. The silica coating + silane group showed mixed failures. CONCLUSIONS: Sandblasting + silane and silica coating + silane applications on debonded ceramic bracket base can produce bond strengths comparable with new brackets.

Orthodontic bonding to several ceramic surfaces: are there acceptable alternatives to conventional methods?

INTRODUCTION: The objectives of this study were to determine the effects of various surface conditioning methods on 3 types of ceramic materials (feldsphatic, leucite-based, and lithia disilicate-based) in orthodontic bonding. METHODS: A total of 210 ceramic disk samples were fabricated and divided into 3 groups. In each group, 5 subgroups were prepared by sandblasting; sandblasting and hydrofluoric (HF) acid; sandblasting and silane; sandblasting, HF acid, and silane; and tribochemical silica coating and silane. Mandibular incisor brackets were bonded with light-cured adhesive. The samples were stored in water for 24 hours at 37 degrees C and then thermocycled. Shear bond tests were performed, and the failure types were classified with adhesive remnant index scores. RESULTS: In all 3 ceramic groups, the lowest shear bond strength values were found in the sandblasted-only samples. For the feldspathic and lithia disilicate-based ceramic, the highest bond strength values were obtained with silica coating (15.2 and 13.2 MPa, respectively). For the leucite-based ceramic, HF without silane produced the highest bond strength value (14.7 MPa), but comparable values were obtained with silicatization also (13.4 MPa). CONCLUSIONS: The silica-coating technique could replace the other conditioning techniques in bonding brackets to ceramic. However, debonding must be done carefully because of the risk of porcelain fracture.

Two different applications of Class II elastics with nonextraction segmental techniques.

OBJECTIVE: To evaluate the relative effects of Class II elastics applied directly with utility arches (UAs) or with the Reciprocal Mini-Chin Cup (RMCC) appliance. MATERIALS AND METHODS: Thirty patients with Class II division 1 malocclusion were included. Fifteen of them were treated with the RMCC appliance and the other 15 treated with Class II elastics on UAs. Lateral cephalograms of an additional 15 untreated persons having the same characteristics as the treatment groups were used as a control group. RESULTS: The mean control period was 10 months. Class I molar and canine relationships were achieved in a mean treatment time of 4.6 months with the RMCC appliance and in 8.5 months with the elastics on UAs. The amount of overjet reduction was 4.7 mm in the RMCC group (87.87% dental) and 5.2 mm in the UA group (80.76% dental). The molar correction was 4.5 mm in the RMCC group (87.36% dental) and 2.0 mm in the UA group (51.47% dental). The anterior lower facial height increased in both of the treatment groups. CONCLUSIONS: The RMCC appliance is a valuable alternative for Class II elastic use in Class II cases in which the upper molars need to be moved to the distal more than the upper incisors.

The effect of food simulants on porcelain-composite bonding.

PURPOSE: The purpose of this study was to evaluate the in vitro effects of food simulants on the bond strength of brackets to porcelain surfaces. MATERIALS AND METHODS: One hundred and eighty porcelain-fused to metal specimens were fabricated. Samples were divided into 3 groups including 60 specimens each. Different surface treatment methods were applied to each group and these were: sandblasting (SB), etching with orthophosphoric acid (OPA) and etching with hydrofluoric acid (HFA). After the surface treatments, the brackets were bonded to the center of each sample with a light-curing orthodontic composite adhesive. Then each group was divided into five test subgroups and one control subgroup each consisting of 10 specimens. The test groups were conditioned for 90 days at 37 degrees C as follows: water, 0.02N citric acid, heptane, 8% ethanol aqueous solution and 50% ethanol aqueous solution. The control specimens were stored at room temperature in air. Shear force was applied to the porcelain-bracket interface by using a universal testing machine with a crosshead speed of 1 mm/min until debonding occurred. The shear bond strength was calculated by dividing the maximum load by the cross-sectional area of the bracket to give the results in megapascals (MPa). The statistical evaluations were made by using analysis of variance. Whenever a significance was detected, Bonferroni tests were performed for post hoc analyses. RESULTS: Fifty percent ethanol conditioned specimens for all surface treatment groups showed lower shear bond strength values. HFA group showed significantly higher shear bond strength values when compared with other groups (P < 0.05). For all porcelain surface treatment groups, control groups showed statistically significant higher shear bond strength values (P < 0.05). CONCLUSION: The results of this in vitro study show that food simulants significantly decrease the bond strength between bracket and porcelain surface.

Multidisciplinary approach to the rehabilitation of a crown-root fracture with original fragment for immediate esthetics: a case report with 4-year follow-up.

Dental practitioners frequently encounter dentoalveolar traumas. According to the severity of the trauma, a large spectrum of complications such as isolated tooth fracture, dentoalveolar fracture or fracture at maxillofacial region may occur. If the isolated tooth fracture occurs particularly at anterior region, the rehabilitation should satisfy both esthetic and functional problems. An unrestorable tooth should be extracted and this leads to more complex treatments such as implant or conventional prosthetic rehabilitations, which will restore the function, but impair the esthetics. Recently, powerful new generation dual-cured resin composites have been produced for reattachment of original fractured fragments. In this case, we presented treatment of oblique crown-root fracture of a maxillary central tooth from enamel-cement junction by the reattachment technique. We used dual cured resin composite (Panavia F) and a self-tapping screw-post (Dentatus) for reattaching the crown fragment. Orthodontic treatment was applied for intruding and leveling the tooth. Four years after treatment, the tooth exhibited good esthetics, good periodontal health and normal function. However, minimal relapse occurred in spite of orthodontic treatment. In conclusion, the reattachment technique is an alternative method, which offers satisfactory esthetic and functional rehabilitation of the fractured teeth.

Porcelain surface treatment by laser for bracket-porcelain bonding.

INTRODUCTION: The purposes of this study were to investigate the effect of laser irradiation on the adhesion of brackets bonded to feldspathic porcelain and to compare it with brackets bonded with conventional techniques. METHODS: One hundred porcelain-fused-to-metal specimens were divided into 10 groups of 10. The treatment groups were sandblasted (SB), sandblasted with silane (SB+S), orthophosphoric acid (OFA), orthophosphoric acid with silane (OFA+S), hydrofluoric acid (HFA), hydrofluoric acid with silane (HFA+S), laser etched (L), laser etched with silane (L+S), glazed (Control 1/C1), and deglazed (Control 2/C2). Five other specimens were irradiated by 2-, 3-, 5-, 10-, and 15-watt superpulse carbon dioxide (CO2) laser for 20 seconds and examined by scanning electron microscopy. Metal brackets were bonded with a self-cure composite material and the specimens were stored in water at 37 degrees C for 24 hours and then thermocycled in water baths between 5 degrees C and 55 degrees C 500 times. Bond strength was determined in megapascals (MPa) by shear test at 1 mm/minute crosshead speed. Bond failure modes were observed under stereomicroscope. For the statistical analysis, 1-way ANOVA and Tamhane post hoc test were used. RESULTS: Statistical analysis showed significant differences between the groups at the .05 level. The HFA+S group yielded the highest mean strength (15.07 +/- 1.44). This was followed by SB+S (13.81 +/- 2.00), HFA (10.78 +/- 0.62), OFA+S (10.73 +/- 1.12), L+S (8.25 +/- 0.90), L (6.26 +/- 0.58), C2 (2.45 +/- 0.54), OFA (2.36 +/- 0.41), SB (2.04 +/- 0.41), and C1 (1.64 +/- 0.33). The bond failure modes of HFA and silane groups, except L+S, were cohesive in porcelain. Control groups and other test groups showed adhesive failure. Only irradiation by 2 watts for 20 seconds provided a porous surface texture without cracks. CONCLUSIONS: Two-watt/20 second superpulse CO2 laser irradiation might be an alternative conditioning method for pretreating ceramic surfaces. Increased bond strength can be achieved by silanation after CO2 laser irradiation.

Tooth-size ratio for patients requiring 4 first premolar extractions.

INTRODUCTION: The relationship between total mesiodistal widths of the maxillary and mandibular teeth is an important factor in orthodontic treatment planning. The purposes of this article are to report a mathematical tooth-size ratio specifically designed for patients needing the extraction of 4 first premolars and to compare the anterior "6" and overall "12" ratio values reported by Bolton with the calculated anterior "6" and overall "10" ratio values obtained from data in this study. METHODS: This study was conducted in 3 phases. In the first 2 phases, we used the peer assessment rating and ideal cephalometric norms to select 53 ideal posttreatment models of patients who had had 4 premolars extracted. In the third phase, the mean overall "10" ratio and the mean anterior "6" ratio were calculated for the selected models. Bolton's mean overall "12" (91.3%) and anterior "6" ratios (77.2%) were compared statistically with calculations derived from this study by using 1-sample t test. RESULTS: The mean overall "10" ratio and the mean anterior "6" ratio were found to be 89.28 +/- 1.07% and 77.68 +/- 1.12%, respectively. Although the difference in anterior ratio was not significantly different from Bolton's anterior "6" ratio, there was a statistically significant difference between Bolton's study and our study in overall ratio. CONCLUSIONS: The mathematical tooth size overall ratio of 89.28% was determined for patients requiring the extraction of 4 first premolars and is recommended for use in diagnosis and treatment planning.

Multidisciplinary approach for the rehabilitation of dentoalveolar trauma.

Satisfactory dental rehabilitation of dentoalveolar trauma requires intense effort and time. Usually multidisciplinary treatment planning and teamwork are necessary to deal with multitask problems associated with these cases. Dental implants have been successfully used for replacement of missing teeth, but in trauma cases insufficient alveolar bone hinders implantation. In this report we present the multidisciplinary approach for the treatment of a trauma case. Maxillary segmental alveolar osteotomy in conjunction with interpositional and onlay bone grafting was performed to prepare the site for placement of osseointegrated implants. Titanium microplate and screws were used to provide orthodontic anchorage for intrusion of the extruded mandibular incisors. The patient was rehabilitated by implant supported fixed partial denture 6 months after implant placement.

Asymmetric maxillary expansion (AMEX) appliance for treatment of true unilateral posterior crossbite.

The aim of this study was to evaluate the effects of an asymmetrical maxillary expansion (AMEX) appliance. Patients with true unilateral posterior crossbites were included in the study. The treatment group consisted of 18 patients who had a mean age of 14 +/- 2.3 years. Treatment effects were evaluated on posteroanterior radiographs, dental casts, and photographs of the dental casts. All unilateral posterior crossbites were corrected in a mean expansion treatment time of 3.3 +/- 0.48 months. As a result of expansion, maxillary interfirst molar, interfirst and second premolar, and intercanine arch widths increased significantly. Comparison of the 2 sides showed that the teeth on the crossbite side moved and tipped more buccally than the teeth on the noncrossbite side. Of the total expansion gained, 75.8% to 91.7% was due to the buccal movements of the teeth on the noncrossbite side. The AMEX appliance was found to be effective in correcting true unilateral posterior crossbites, and therefore it can be recommended for clinical use.