Tahir Karaman

Comparison of the effects of different loading locations on stresses transferred to straight and angled implant-supported zirconia frameworks: a finite element method study

The paper presents three-dimensional (3D) finite element models of straight and angled implants and their zirconium-based superstructures. The key objective was to compare the influence of different loading conditions on the stress distribution of straight and angled implants and the zirconia frameworks. 3D finite element straight- and angled-implant models of a mandibular section of bone with missing second molars and their zirconium-based superstructures were used. The straight and angled implants were 4.7 × 13-mm screw-type dental implant systems. Total loads of 300 N were applied in a vertical direction and in an oblique (30° to the vertical) direction buccolingually. Maximum and minimum von Mises stress values of the titanium structures (abutment and implant body) and zirconia frameworks were calculated. When the two groups were examined, the highest stress value was in the zirconia framework of the angled implant-supported model with an oblique loading force (731.46 MPa). The lowest stress values were concentrated in the straight implant-supported model. Thus, the stress values in the angled implant-supported crown were higher than those in the straight implant-supported model. Stress values with oblique loading forces were higher than the values with vertical loading forces. The highest stress value in the zirconia framework was similar to the ultimate strength of the zirconia.

Is there a relation between dental anxiety, fear and general psychological status?

Background Dental anxiety is a widespread problem in many populations. This problem can be a barrier to dental care and may lead to poor oral health. Dental anxiety may be related to psychological status. Aims The aim of the present study was to assess the levels of dental anxiety, dental fear, Beck Depression, and state-trait anxiety according to age, gender and education level in patients at the periodontology clinic in the Diyarbakır Mouth and Dental Health Center. Study Design A total of 231 patients (115 males, 116 females) filled out dental fear scale (DFS), dental anxiety scale (DAS), Beck Depression Inventory (BDI), state-trait anxiety inventory-state (STAI-S), and state-trait anxiety inventory–trait (STAI-T) questionnaires, and evaluations of DFS, DAS, BDI, STAI-S, and STAI-T were conducted according to age, gender, and education level. Results The mean DFS, DAS, BDI, STAI-T, and STAI –S were 45.64, 9.15, 13.16, 38.90, and 40.18, respectively. There was a significant association among DFS, DAS, BDI, STAI-S, and STAI-T (p < 0.05). These surveys scores were significantly higher in females than males (p < 0.05). The results of this study indicated that gender age and education level have important effects on DFS, DAS, BDI, STAI-S, and STAI-T (p < 0.05). Conclusion Dental anxiety and dental fear were found to be related to psychological status (BDI, STAI-S, and STAI-T) over time. There are some patients with unaddressed psychological distress.

Effects of Local and Systemic Zoledronic Acid Application on Titanium Implant Osseointegration: An Experimental Study Conducted on Two Surface Types

Abstract The aim of this study was to evaluate the effects of local and systemic zoledronic acid (ZA) applications on titaniumoksit ceramic blasted (TiO-CB)- and sandblasted large acid-grit (SLA)-surfaced titanium implant osseointegration. Twelve New Zealand White rabbits were used in the study, divided into 6 groups: the TiO-CB (TiO-CB-CNT) (n = 2) and SLA (SLA-CNT) (n = 2) control groups in which TiO-CB- and SLA-surfaced titanium implants were surgically inserted into rabbit tibias but no treatment was applied; the TiO-CB (TiO-CB-LZA) (n = 2) and SLA (SLA-LZA) (n = 2) local ZA groups in which 1 mL of normal saline solution containing 2 mg of ZA was injected into sockets and after this the implants were integrated; and the TiO-CB (TiO-CB-SZA) (n = 2) and SLA (SLA-SZA) (n = 2) systemic ZA groups in which a single infusion of 0.1 mg/kg of ZA was administered during surgical implant insertion. Following a period of osseointegration, bone implant contact (BIC) was recorded as a proportion of the total implant surface length in direct contact with the bone. Results of this study indicate that BIC was greater in the systemic ZA application groups than in the local ZA application groups, and BIC was greater in the local ZA groups than in the controls. Statistically significant differences in BIC were not detected between the TiO-CB- and SLA-surfaced implants in all the groups. Furthermore, this study did not reveal significant differences between the 2 types of surfaces due to similar average roughness values. Overall, systemic ZA application was found to be more effective in increasing BIC than local ZA application based on the results obtained by testing 2 implant surfaces.

Spectrophotometric Evaluation of Anterior Maxillary Tooth Color Distribution According to Age and Gender: Anterior Maxillary Tooth Color Measurements

PURPOSE To determine the effects of age and gender on the color distribution of the right maxillary central, lateral incisors, and canine teeth. MATERIALS AND METHODS The tooth color was measured using the VITA Easyshade V spectrophotometer with a total of 202 volunteers (89 men, 113 women). The age distribution in this study was between 15 and 70 years old (average: 31). A grey background color was used to prevent background reflection while performing the color measurements. RESULTS According to the VITAPAN Classical shade guide, the tooth color distribution of the central and lateral incisors showed a maximum of A2, with a maximum of B3 for the canine teeth. When comparing the International Commission on Illumination L* , a* , and b* values (CIELab color space coordinates) of the teeth with subject gender, statistically significant differences were not found between gender and the L* and b* values (p > 0.05); however, a statistically significant difference was observed between gender and the a* values (p < 0.05). CONCLUSION When the distribution ratio of tooth color was examined, different ratios were determined based on gender and age and between the maxillary central, lateral incisors, and canine teeth. A uniform tooth color should not be chosen for anterior restorations, and factors such as gender and age should be considered when making a color selection for patients.

MANYETİK REZONANS GÖRÜNTÜLEMENİN DİŞ HEKİMLİĞİNDE KULLANIMI VE DENTAL MATERYALLERE ETKİLERİ

Radyolojik goruntuleme yontemlerinden biri olan Man- yetik Rezonans Goruntuleme, hastaliklarin tanisina cok onemli katkilari bulunmasindan dolayi yaygin bir sekil- de medikal alanda kullanilmaktadir. Bu goruntuleme tekniginde kuvvetli manyetik alan olusmasi ve vucutta bulunan metalik objelerin bu manyetik alandan etkile- simleri hasta acisindan potansiyel saglik riskleri olustu- rabilmektedir. Dis hekimligi alaninda yaygin bir sekilde kullanilan Dental implantlar, Ortodontik braketler ve teller, Metal destekli sabit ve hareketli restorasyonlar vb. gibi iceriginde metal bulunan objelerin varliginda Manyetik Rezonans Goruntulemesi esnasinda olusabi- lecek manyetik alan etkilesimlerinin yeterince bilinmesi gerekir. Goruntuleme esnasinda hasta acisindan olusa- bilecek riskleri en asgari duzeye indirebilmek icin vu- cutta bulunan ve manyetik alandan etkilenen metalik objeler ile ilgili gerekli tedbirlerin alinmasi gerekir. Anahtar Kelimeler: Manyetik Rezonans Goruntuleme, dental alasimlar, manyetik alan etkilesimi MAGNETIC RESONANCE IMAGING IN DENTISTRY AND ITS EFFECT ON DENTAL MATERIALS ABSTRACT Magnetic resonance imaging (MRI) is one of the radiologic imaging techniques, using widely in medical field due to significant contribution to the diagnosis of diseases. Formation of the strong magnetic field and its interaction with metallic objects in the body may cause potential risks for patient. In the presence of metal containing objets in dentistry such as dental implants, orthodontic brackets and wires, metal-supported fixed and removable restorations, adequate information about the features of magnetic field and its interaction with the metallic objects should be known. To take necessary measures related with the magnetic field interactions, will reduced risk level during imaging. Keywords: Magnetic Rezonance Imaging, dental alloys, magnetic field interactions

YAŞ VE CİNSİYETE GÖRE MAKSİLLER SANTRAL DİŞ RENGİ DAĞILIMININ SPEKTROFOTOMETRE İLE ÖLÇÜLMESİ

Amac: Maksiller santral disin renk dagiliminin belirlenmesi ve yas ile cinsiyetin dis rengi dagilimina etkisinin incelenmesi hedeflenmistir. Gerec ve Yontem: Calismamizda yaslari 15 ile 76 arasinda (yas ortalamasi 32) olan 345 gonullu birey yer almaktadir. Gonullulerin 183’ u erkek (%53), 162’si kadindir (%47). Calismada yer alan hastalarin sag maksiller santral dis rengi olcumleri Vita EasyShade V spektrofotometre cihazi ile gerceklestirilmistir. Cihazin ucu sag maksiller santral dislerin labial yuzunun orta uclusune dik tutularak 3 olcum gerceklestirildi ve ortalamasi alindi. Elde edilen veriler Vitapan Classical ve VITA Toothguide 3D-MASTER skalasina gore kaydedildi. Verilerin istatistiksel olarak analizi gerceklestirildi. Bulgular: Cihaz tarafindan secilen dis rengi dagilimi incelendiginde Vitapan Classical renk skalasina gore en cok A2 (%22,9), VITA Toothguide 3D-MASTER renk skalasina gore en cok 2M2 (%21,2) dis rengi olculmustur. Yapmis oldugumuz dis rengi olcumu sonuclarina gore Vita EasyShade V cihazi tarafindan B1, 4L2.5, 4M3 ve 5M3 renkleri saptanamamistir. Sonuc: Calismamizda elde edilen veriler isiginda cinsiyet ile dis rengi dagilimi arasinda istatistiksel olarak anlamli bir sonuc bulunmazken ( p>0.05 ) , yas dagilimi ile dis rengi dagilimi arasinda istatistiksel olarak anlamli bir sonuc bulundu ( p 0.05 ) . Keywords: Tooth color, spectrophotometer, dental shade guides

Measuring the resistance of different substructure materials by sticking them to dentine with two different resin cements in vitro

INTRODUCTION The resistance of three different substructure materials - metal (Cr-Co), zirconium (Zr), and ceramics (IPS Empress II) - was measured by sticking them to dentine with two different resin cements, a dual-cure resin cement (Panavia F 2.0 Light) and a self-adhesive resin cement (BisCem). MATERIALS AND METHODS In an in vitro study, 72 central upper front teeth were selected with no decay or apparent breakage and with complete development, removed for periodontal reasons. Labial and incisal surfaces of all teeth were prepared. Molds were obtained to prepare metal (Co-Cr), Zr, and ceramic (IPS Empress II) blocks for use in the study. The compressive strengths of the obtained material infrastructures were examined after thermal cycle processing by performing cementation to the teeth with two different cements. The data obtained were analyzed statistically. The Mann-Whitney U-test was used for comparisons of the groups with two options, and Kruskal-Wallis variance analysis was used to compare more than two groups. P<0.05 were considered statistically significant. RESULTS While the highest result between samples was 117.86 ± 47.94 N in the dual-cure (Panavia)-ceramic group, the lowest value was observed at 6.53 ± 3.12 N in the self-adhesive (BisCem)-metal group. There was a significant difference between dual-cure (Panavia) and self-adhesive (BisCem) groups. CONCLUSION In this study, we measured the bond strength; our most durable resistance groups were found to be, in order, Panavia-ceramics >Panavia-metal >Panavia-Zr >self-adhesive-ceramics >self-adhesive-Zr >and self-adhesive-metal.

Evaluation and comparison of the marginal adaptation of two different substructure materials.

PURPOSE In this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations. MATERIALS AND METHODS Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearsons correlation analysis was also performed to assess relationships between variables. RESULTS According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface. CONCLUSION Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.