Hasan Onder Gumus

Computerized analysis of occlusal contacts in bruxism patients treated with occlusal splint therapy

PURPOSE Occlusal splints are commonly used to prevent tooth wear caused by bruxism. However, the effects of splints on occlusion are still unclear. Although it is rarely alluded in literature, splints can provoke severe occlusal alterations and other complications. This study was aimed to identify differences in the responses of individuals with bruxism and healthy individuals to a full-arch maxillary stabilization splint in terms of occlusal changes. MATERIALS AND METHODS Occlusal contacts in 20 (5 male, 15 female) bruxism patients and 20 (5 male, 15 female) controls with normal occlusion were evaluated before and after occlusal splint therapy. T-Scan III, a computerized occlusal analysis system, was used to simultaneously measure occlusion and disclusion times as well as left-right and anterior-posterior contact distributions before splint therapy and 3 months after therapy. Wilcoxon and Mann-Whitney U tests were used for statistical analyses (α=.05). RESULTS No differences were found in the posterior contact of bruxism patients before and after stabilization splint treatment. However, differences in posterior contact were observed between bruxists and normal individuals prior to treatment, and this difference disappeared following treatment. CONCLUSION The results of this study showed the use of a stabilization splint may not have an effect on occlusion. However, the area of posterior occlusal contact among bruxists was found to be greater than that of normal individuals. According to this study, the clinical use of splints may be harmless.

Effect of fluid contamination on reverse torque values in bone-level implants.

Introduction: Screw loosening is one of the most common mechanical complications within the prosthetic components of dental implants. Clinicians must know if reverse torque values (RTVs) are affected by contamination of the implant abutment screw hole with either blood, saliva or chlorhexidine. Methods: Forty implants were divided into 4 groups (n = 10). Implants were embedded in epoxy resin and placed in a digital torque meter. Screw holes of 30 implants were contaminated with either chlorhexidine (CG), fresh human saliva (SG), or blood (BG), and the remaining noncontaminated screws served as a control group (NC). Abutment screws were tightened using a hand-held torque meter (25 N·cm). Thermocycling (1500 cycles) was performed, and abutment detorque values were calculated using the digital torque meter. Results: RTVs were lower than insertion torque values for all groups. According to Tukey HSD Test, blood contamination of abutment screws resulted in significantly lower RTVs (18.950 ± 2.641 N·cm) when compared with controls. Conclusions: Blood contamination of abutment screw holes was shown to significantly decrease RTVs. Blood contamination may result in greater loosening of implant screws in clinical practice.

Effect of different provisional cement remnant cleaning procedures including Er:YAG laser on shear bond strength of ceramics

PURPOSE The purpose of this study was to evaluate the effect of provisional cement removal by different dentin cleaning protocols (dental explorer, pumice, cleaning bur, Er:YAG laser) on the shear bond strength between ceramic and dentin. MATERIALS AND METHODS In total, 36 caries-free unrestored human third molars were selected as tooth specimens. Provisional restorations were fabricated and cemented with eugenol-free provisional cement. Then, disc-shaped ceramic specimens were fabricated and randomly assigned to four groups of dentin cleaning protocols (n = 9). Group 1 (control): Provisional cements were mechanically removed with a dental explorer. Group 2: The dentin surfaces were treated with a cleaning brush with pumice Group 3: The dentin surfaces were treated with a cleaning bur. Group 4: The provisional cements were removed by an Er:YAG laser. Self-adhesive luting cement was used to bond ceramic discs to dentin surfaces. Shear bond strength (SBS) was measured using a universal testing machine at a 0.05 mm/min crosshead speed. The data were analyzed using a Kolmogorov Smirnov, One-way ANOVA and Tukey HSD tests to perform multiple comparisons (α=0.05). RESULTS The dentin cleaning methods did not significantly affect the SBS of ceramic discs to dentin as follows: dental explorer, pumice, cleaning bur, and Er:YAG laser. CONCLUSION The use of different cleaning protocols did not affect the SBS between dentin and ceramic surfaces.

Effect of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with different CAD-CAM technologies

Statement of problem The use of computer‐aided design and computer‐aided manufacturing (CAD‐CAM) for metal‐ceramic restorations has increased with advances in the technology. However, little is known about the marginal and internal adaptation of restorations fabricated using laser sintering (LS) and soft milling (SM). Moreover, the effects of repeated ceramic firings on the marginal and internal adaptation of metal‐ceramic restorations fabricated with LS and SM is also unknown. Purpose The purpose of this in vitro study was to investigate the effects of repeated ceramic firings on the marginal and internal adaptation of metal‐ceramic copings fabricated using the lost wax (LW), LS, and SM techniques. Material and methods Ten LW, 10 LS, and 10 SM cobalt‐chromium (Co‐Cr) copings were fabricated for an artificial tooth (Frasaco GmbH). After the application of veneering ceramic (VITA VMK Master; VITA Zahnfabrik), the marginal and internal discrepancies of these copings were measured with a silicone indicator paste and a stereomicroscope at ×100 magnification after the first, second, and third clinical simulated ceramic firing cycles. Repeated measures 2‐way ANOVA and the Fisher LSD post hoc test were used to evaluate differences in marginal and internal discrepancies (&agr;=.05). Results Neither fabrication protocol nor repeated ceramic firings had any statistically significant effect on internal discrepancy values (P>.05). Marginal discrepancy values were also statistically unaffected by repeated ceramic firings (P>.05); however, the fabrication protocol had a significant effect on marginal discrepancy values (P<.001), with LW resulting in higher marginal discrepancy values than LS or SM (P<.05). Marginal discrepancy values did not vary between LS and SM (P>.05). Conclusions All groups demonstrated clinically acceptable marginal adaptation after repeated ceramic firing cycles; however, the LS and SM groups demonstrated better marginal adaptation than that of LW group and may be appropriate clinical alternatives to LW.

Prosthetic rehabilitation of a patient with a resected right temporomandibular joint

This case report presents the prosthodontic rehabilitation of a patient with a resected right mandible, caused by an accident. Right condyle, ramus, and the posterior part of ramus were affected by the accident. These structures were resected, and the mandible was positioned toward the surgical area and a facial asymmetry was occurred. The patient was treated with a bar-retained maxillar denture with a guide ramp and an implant-supported fixed mandibular prosthesis.

Efficacy of polishing kits on the surface roughness and color stability of different composite resins

Objective: Different polishing kits may have different effects on the composite resin surfaces. The aim of this study was to evaluate the surface roughness and color stability of four different composites which was applied different polishing technique. Materials and Methods: Thirty specimens were made for each composite resin group (nanohybrid, GrandioSo-GS; nanohybrid, Clearfil Majesty Esthetic-CME; hybrid, Valux Plus-VP; micro-hybrid, Ruby Comp-RC; [15 mm in diameter and 2 mm height]), with the different monomer composition and particle size from a total of 120 specimens. Each composite group was divided into three subgroups (n = 10). The first subgroup of the each composite subgroups served as control (C) and had no surface treatment. The second subgroup of the each composite resin groups was polished with finishing discs (Bisco Finishing Discs; Bisco Inc., Schaumburg, IL, USA). The third subgroup of the each composite resin was polished with polishing wheel (Enhance and PoGo, Dentsply, Konstanz, Germany). The surface roughness and the color differences measurement of the specimens were made and recorded. The data were compared using Kruskal–Wallis test, and regression analysis was used in order to examine the correlation between surface roughness and color differences of the specimens (α = 0.05). Results: The Kruskal–Wallis test indicated significant difference among the composite resins in terms of ΔE (P < 0.05), and there was no statistically significant difference among composite resins in terms of surface roughness (P > 0.05). Result of the regression analysis indicated statistically significant correlation between Ra and ΔE values (P < 0.05, r2 = 0.74). Conclusion: The findings of the present study have clinical relevance in the choice of polishing kits used.

Accuracy of torque-limiting devices: A comparative evaluation

Statement of problem. To prevent the loosening of implant screws, clinicians should be aware of the output torque values needed to achieve the desired preload. Accurate torque‐control devices are crucial in this regard; however, little information is currently available comparing the accuracy of mechanical with that of electronic torque‐control devices. Purpose. The purpose of this in vitro study was to identify and compare the accuracy of different types of torque‐control devices. Material and methods. Devices from 5 different dental implant manufacturers were evaluated, including 2 spring‐type (Straumann, Implance) mechanical devices (MTLD), 2 friction‐type (Biohorizons, Dyna) MTLDs, and 1 (Megagen) electronic torque‐control device (ETLD). For each manufacturer, 5 devices were tested 5 times with a digital torque tester, and the average for each device was calculated and recorded. The percentage of absolute deviations from the target torque values (PERDEV) were calculated and compared by using 1‐way ANOVA. A 1‐sample t test was used to evaluate the ability of each device to achieve its target torque value within a 95% confidence interval for the true population mean of measured values (&agr;=.05 for all statistical analyses). Results. One‐way ANOVAs revealed statistically significant differences among torque‐control devices (P<.001). ETLD showed higher PERDEVs (28.33 ±9.53) than MTLDs (P<.05), whereas PERDEVS of friction‐type (7.56 ±3.64) and spring‐type (10.85 ±4.11) MTLDs did not differ significantly. In addition, devices produced by Megagen had a significantly higher (P<.05) PERDEV (28.33 ±9.53) other devices, whereas no differences were found in devices manufactured by Biohorizons (7.31 ±5.34), Dyna (7.82 ±1.08), Implance (8.43 ±4.77), and Straumann (13.26 ±0.79). However, 1‐sample t tests showed none of the torque‐control devices evaluated in this study were capable of achieving their target torque values (P<.05). Conclusions. Within the limitations of this in vitro study, MTLDs were shown to be significantly more accurate than ETLDs. However, none of the torque‐control devices evaluated were able to meet their target torque values successfully.

An Alternative Healing Abutment Production Technique for Deeply Placed Implants: A Case Report

A healing abutment, also known as a ‘‘gingival former’’ or ‘‘healing cap,’’ is placed into an implant to help facilitate soft-tissue healing around the implant after firstor second-stage surgery. Conventional prefabricated gingival formers are designed for machined abutments and are produced in several lengths in order to project through soft tissue into the oral cavity. However, limited bone availability sometimes necessitates the deep subgingival placement of an implant. The overlying soft tissue may be too thick to be transversed by the highest length of conventional healing abutment especially in cleft palate patients and patients with severe bone resorption. The anatomical changes that occur with the edentulous maxilla after cleft plate and implant surgery can be a challenge to redevelop during the prosthodontic process. For instance, a large part of the impression coping may be placed subgingivally, complicating the preservation of the soft-tissue form that is important for optimizing the final prosthetic outcome. The protected tissue profile can be duplicated simply during the impression process, allowing for accurate fabrication of a restoration in harmony with ideal tissue architecture at the day of restoration’s placement. Prefabricated healing abutments may fail to provide support for supracrestal soft tissue in deeply placed implant sites. In such cases, an alternative technique may be required to achieve ideal tissue form. One such technique involves the production of a custom-made healing abutment. The use of a modified healing abutment has been recommended to overcome the problem of deeply placed implants; however, the modification of an implant-transfer piece as a healing abutment has not been described in the literature. This article describes a technique for creating a customized implant-healing abutment using an implant-transfer piece. CASE REPORT

Effects of metal surface grinding at the porcelain try-in stage of fixed dental prostheses.

PURPOSE This study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples. MATERIALS AND METHODS Ninety-one square prism-shaped (1 × 1 × 1.5 mm) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level. RESULTS The samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P<.05). SBS values of none of the groups differed from those of the control group (P>.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05). CONCLUSION Grinding the inner metal surface did not affect the metal-porcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength.

Diş hekimliği fakültelerinde kullanılan farklı diş ünitlerinin su ünitlerinin su sistemlerinin geri akım kontaminasyonu açısından değerlendirilmesi

evaluation of escape-back avoiding system connected to water system of different dental units in dentistry faculties Background: The purpose of the study is to search the efficiency of escape-back avoiding systems connected to dental units for a long time period and the determination of cross infection risks because of escape-back systems using in different branches. Methods: Study groups are planned among between three different branches of dentistry. The difference between materials which are obtained from these three different study groups have been evaluated microbiologically in terms of the presence of bacteria. Results: However various colonies of bacteria were isolated for all the groups, it has been resulted that most of the reproductive microorganisms in study groups were also isolated from environment and oral flora. Conclusion: It has been concluded that providing contamination avoiding systems for dental units is extremely important and however dental unit systems must have been controlled frequently and revaluated for the necessity of renewal.