Mehmet Oguz Oztoprak

Debonding of ceramic brackets by a new scanning laser method

INTRODUCTION The purpose of this in-vitro study was to develop a new method to debond ceramic brackets by scanning with an Er:YAG laser. METHODS Sixty bovine mandibular incisors were randomly divided into 2 groups of 30. Polycrystalline ceramic brackets were placed on their labial surfaces by using the orthodontic composite adhesive Transbond XT (3M Unitek, Monrovia, Calif) and light cured for a total of 40 seconds. The first group was the control group, with no laser application performed. The Er:YAG laser was used on each bracket in the study group at 4.2 W for 9 seconds with the scanning method. The force required for debonding the brackets was applied 45 seconds after laser exposure. Shear bond strengths were measured in megapascals with a universal testing machine, and adhesive remnant index scores were assigned to each specimen. RESULTS Statistically significant (P <0.001) lower shear bond strengths were found in the laser group (9.52 MPa) compared with the control group (20.75 MPa). Likewise, the adhesive remnant index scores were statistically different (P <0.001); the laser group had twice as many samples with adhesive, with the adhesive remnant index scores of 2 or 3. CONCLUSIONS The application of the Er:YAG laser with the scanning method is effective for debonding ceramic brackets by degrading the adhesive through thermal softening.

Pulpal Thermal Changes following Er-YAG Laser Debonding of Ceramic Brackets

Lasers are effective in debonding ceramic brackets. Unfortunately, while reducing the adhesive bond strength, lasers are also reported to increase pulpal temperature. The aim of this study was to evaluate the shear bond strengths and temperature increase levels after debonding ceramic brackets using an Er-YAG laser with or without water-cooling. Sixty polycrystalline upper premolar ceramic brackets were placed on the labial surface of sixty human premolar teeth which were randomly divided into three groups of twenty. A laser pulse at 5 W for 9 seconds was delivered to each bracket in both study groups either with water-cooling (water group) or without water-cooling (waterless group) using an Er-YAG laser. Debonding was performed 45 seconds after laser exposure and shear bond strengths were measured. Data comparison revealed a statistically significant difference between the groups. Mean temperature increases of 2.41°C and 4.59°C were recorded for the water and waterless laser groups, respectively. The shear bond strength value for the control group was 22.76 MPa and 10.46 and 6.36 MPa for the water and waterless laser groups, respectively. The application of Er-YAG laser with water-cooling was an efficient and safe method of debonding ceramic brackets.

Effect of Er:YAG laser on debonding strength of laminate veneers

Objective: The purpose of this study was to evaluate the debonding strength of laminate veneers after using erbium-doped: yttrium aluminium garnet (Er:YAG) laser. Materials and Methods: A total of 60 bovine mandibular incisor teeth were divided into two groups (n = 30). Cylindrical specimens (0.7 mm × 5 mm) were fabricated from Empress II ceramic. Then, they were cemented to incisors using dual-cured resin cement (Variolink II). In the first group, no laser application was performed. The Er:YAG laser was applied on each laminate veneer at the test group for 9 s by using the scanning method. Shear force to remove the laminate veneers were applied with universal testing machine at a crosshead speed of 1 mm/min. Results: Results of this study exhibited significant differences between the control (27.28 ± 2.24 MPa) and test group (3.44 ± 0.69 MPa) (P < 0.05). Conclusion: This study shows that application of Er:YAG laser decreased the bond strength of laminate veneers.

Mini-İmplantların Devrilmesini Önlemede Yeni Bir Yaklaşım

OZET Amac: Calismanin amaci, ortodontik yuk altinda mini-implant deplasman miktarini belirlemek ve mini-implantlarin yaka kismina yerlestirilen yeni tasarlanmis bir aparatin (mini-implant ring - MIR) etkinligini degerlenmektir. Gerecler ve Yontem: Toplam 48 mini-implant sigir kalca kemiginden elde edilen orneklere uygulanmistir. Calisma grubunda 24 mini-implant MIR ile uygulanmis ve kalan mini-implantlar MIR olmadan uygulanarak kontrol olarak ayrilmistir. Tum mini-implantlar vida uzun eksenine dik olacak sekilde 200 g teget yuke tabi tutulmuslar ve vidalarin yer degistirmesi Instron Universal Test Makinesi kullanilarak milimetre cinsinden olculmustur. Yukleme testi sonrasi, her bir mini-implant cikarilmis ve kortikal kemik orneklerinin kalinliklari olculmustur. Orneklerin kortikal kalinligina gore, calisma ve kontrol gruplari, ince ve kalin kortikal kemik olarak alt gruplara ayrilmistir. Bulgular: 200 g kuvvet uygulandiginda, MIR ile uygulanan mini-implantlarin ortalama deplasman degerleri MIR olmadan uyg...

Sınıf II Bölüm 1 Malokluzyonun Üst Orta Keser Çekimli Tedavisi

OZET Bu vaka raporunda sinif II malokluzyona sahip 12 yasindaki bir kiz hastanin renklenmis ve koklerinde rezorpsiyon izlenen ust santral kesici dislerinin cekimi ile ortodontik tedavisi sunulmaktadir.

Prefabrike Elastomerik Aparey ile Sınıf II Maloklüzyonun Düzeltimi: Olgu Raporu

OZET Amac: Bu olgu sunumunda sabit ortodontik tedavi gormek istemeyen, minor rotasyonlari ve diastemalari bulunan Sinif II bolum 1 malokluzyona sahip 11 yasindaki kiz hastanin prefabrike elastomerik Multi-P aygiti ile ortodontik tedavisi anlatilmaktadir.