Ayça Arman

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.

Microleakage beneath ceramic and metal brackets bonded with a conventional and an antibacterial adhesive system.

OBJECTIVE To assess microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial self-etching adhesive. MATERIALS AND METHODS Forty freshly extracted human premolars were randomly assigned to four equal groups and received the following treatments: group 1 = Transbond XT + metal bracket, group 2 = Transbond XT + ceramic bracket, group 3 = Clearfil Protect Bond + ceramic bracket, and group 4 = Clearfil Protect Bond + metal bracket. After photopolymerization, the teeth were kept in distilled water for 1 month and thereafter subjected to thermal cycling (500 cycles). Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage for the adhesive-tooth and bracket-adhesive interfaces from incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction. RESULTS All groups demonstrated microleakage between the adhesive-enamel and bracket-adhesive interfaces. A significant difference was observed among all groups (P < .05) for the microleakage between the bracket-adhesive interface. Metal brackets exhibited significantly more microleakage than did ceramic brackets between the bracket-adhesive interface with either of the adhesives. Clearfil Protect Bond exhibited results similar to Transbond XT. Clearfil Protect Bond may be a choice of adhesive in bracket bonding because of its antibacterial activity and similar microleakage results with the orthodontic adhesive. CONCLUSIONS Metal brackets cause more leakage between an adhesive-bracket interface, which may lead to lower clinical shear bond strength and white-spot lesions.

Profile Changes Associated with Different Orthopedic Treatment Approaches in Class III Malocclusions

The aim of this study was to evaluate and compare the soft tissue effects of chincup (CC), chincup plus bite plate (CC+P), and reverse headgear (RHg) therapies with each other and with an untreated control group (C). The material consisted of lateral cephalometric and hand-wrist films of 59 Class III cases and 20 nontreated control subjects. Thirty-one cases were treated with CC, 14 with CC+P, and 14 with RHg, and Class I relation was achieved. The mean pretreatment ages were approximately 11 years and the observation period was one year. The cephalometric films were analyzed according to the structural superimposition method of Björk. All tracings were double digitized, and the measurements were calculated by a computer program (PORDIOS). Treatment and control changes within the groups and the differences between the groups were analyzed statistically. Forward positioning of the maxilla was significant in the RHg group, whereas the mandible was positioned backward significantly in all the treatment groups. Posterior rotation of the mandible was significant in the CC+P and RHg groups. The overjet increased and the overbite decreased significantly in all the treatment groups. Forward movement of soft tissue A and upper lip was significant in all groups, whereas more pronounced in the CC+P group. The soft tissue changes in the mandibular region were significant in the CC and CC+P groups, whereas in the maxillary region more significant and similar improvements were obtained by CC+P and RHg treatments. Longterm studies are required to confirm the stability of these changes.

Microleakage beneath Ceramic and Metal Brackets Photopolymerized with LED or Conventional Light Curing Units

OBJECTIVE To test the null hypotheses that (1) the type of light curing unit used (quartz-tungsten-halogen [QTH] or light-emitting diode [LED]) would not affect the amount of microleakage observed beneath brackets, and (2) the bracket type used (ceramic or metal) would not influence the amount of microleakage observed beneath brackets. MATERIALS AND METHODS 40 freshly-extracted human premolars were randomly assigned into 4 bonding groups (n = 10/group): group 1, metal bracket + LED-cured Transbond XT; group 2, ceramic bracket + LED-cured Transbond XT; group 3, metal bracket + QTH-cured Transbond XT; and group 4, ceramic bracket + QTH-cured Transbond XT. The teeth were kept in distilled water for 1 month, and thereafter subjected to 500 thermal cycles. Then, specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned, and photographed under a stereomicroscope. Microleakage was scored with regard to the adhesive-tooth interface and the bracket-adhesive interface at both incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction. RESULTS Microleakage was observed in all groups. When an LED curing unit was used for adhesive polymerization, ceramic brackets displayed significantly less microleakage than metal brackets in both tooth-adhesive and bracket-adhesive interfaces. When a QTH curing unit was used, ceramic brackets displayed significantly less microleakage than metal brackets in the bracket-adhesive interface in both gingival and incisal margins. CONCLUSIONS Ceramic brackets cured with LED units were the best combination, demonstrating the lowest microleakage scores.

Comparison of the zygoma anchorage system with cervical headgear in buccal segment distalization

This prospective study aimed to evaluate the effects of the zygoma anchorage system (ZAS) in buccal segment distalization in comparison with cervical headgear (CH). Thirty patients with Class II dental malocclusions were included in the study and were divided into two equal groups: the first group (10 females and 5 males, mean age 14.74 years at T1) received buccal segment distalization with ZAS and the second group (8 females and 7 males, mean age 15.26 years at T1) with CH. The skeletal, dental, and soft tissue changes were measured on cephalograms obtained before (T1) and after (T2) distalization, and these changes were statistically evaluated using a repeated measures analysis of variance, Mann-Whitney U-test, and Wilcoxon test. The Class II buccal segment relationship was corrected to a Class I in an average period of 9.03 +/- 0.62 months in the ZAS group and 9.00 +/- 0.76 months in the CH group. Significant distalization was observed for the posterior teeth in both groups (P < 0.001). Distal tipping of all posterior teeth occurred in the CH group (P < 0.001), but only for the molars in the ZAS group (P < 0.001). The upper incisors retroclined, overjet decreased, and the upper and lower lips retruded in both groups. The ZAS provided absolute anchorage for distalization of the maxillary posterior teeth and can be used as an aesthetic and non-compliant alternative to extraoral traction in the treatment of Class II malocclusions.

Stability of zygomatic plate-screw orthodontic anchorage system: a finite element analysis.

OBJECTIVE To evaluate the biomechanical properties of a standard and a newly designed plate-screw orthodontic anchorage system. MATERIALS AND METHODS A three-dimensional model of the posterior maxilla, including the zygomatic buttress region, was prepared. Insertion of standard and newly designed plates was simulated on the three-dimensional model. The effect of 200 g of orthodontic force on the plate, screws, and zygomatic bone was evaluated in three-dimensional models by finite element analysis. To determine the force distribution, Von Mises stress, principal maximum and minimum stress, and principal maximum and minimum elastic strain values were evaluated. RESULTS In all plate models the highest stresses occurred on the threaded bone site where the force application unit was attached. CONCLUSION Changing the plate configuration did not affect the stress distribution in the newly designed plates. To equalize the force distribution, new plate designs that change the location of the force application unit are required.

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.

Fiber-reinforced technology in multidisciplinary chairside approaches

There is an increasing demand to improve dentofacial esthetics in the adult population. This demand usually requires a close collaboration within the various disciplines of dentistry and the patient at every stage of the therapy. The materials and techniques used by these interdisciplinary clinicians must be conservative and minimally invasive. Fiber-reinforced composite technology offers such solutions for chairside applications. This case report presents two cases where fiber-reinforced ribbon and composite complex was used in a multidisciplinary approach to improve esthetics.

A conservative multidisciplinary approach for improved aesthetic results with traumatised anterior teeth

A subgingival crown-root fracture presents a restorative problem to the clinician because restoration is complicated by the need to maintain the health of the periodontal tissues. If the remaining portion of the root is thought to be enough to support a definitive restoration, the root may be extruded by orthodontic forced eruption after root canal treatment. Extrusion enables the remaining root portion to be elevated above the epithelial attachment. Endodontic posts may be useful in exerting vertical forces to the root for extrusion without buccal tipping. The following case shows multidisciplinary management of a case of dental trauma. Orthodontic forced eruption is incorporated using endodontic posts and restoration with porcelain fused to metal crowns — leading to successful restoration of the traumatised teeth.

Orthodontic and surgical treatment of hemimandibular hyperplasia.

Correction of facial asymmetries is still a major problem in need of an adequate solution. In this case report, the differential diagnosis and treatment strategies of hemimandibular hyperplasia are described with the present patient.