Evaluation of different color measurement methods for determining tooth color.

AIM: The purpose of this study is to develop software at a low cost that enables the detection of tooth colors by capturing photographs using various devices, and to compare its effectiveness with existing expensive methods. MATERIAL AND METHODS: A total of 60 anterior central incisor teeth from 30 individuals were included in the study. The CIELAB values (L,a,b) of each tooth were measured using a spectrophotometer, which is considered the gold standard. Subsequently, photographs of the teeth were taken using four different smartphones (iPhone- Xiaomi) and one digital camera (Canon). These images were then subjected to image processing techniques and compared with measurements obtained through computer-based analysis in order to assess the correlation. Data with three or more groups, the Kruskal-Wallis H test was utilized, and multiple comparisons were conducted using the Dunn test. A significance level of p<0.05 was considered. RESULTS: Upon examining the results of multiple comparisons, a statistically significant difference was observed (p<0.001) between the DeltaE values obtained from the camera of the iPhone and those obtained from the Canon DSLR and Xiaomi cameras. The iPhone cameras yielded result values ranging from 2.68 to 2.90 for DeltaE. CONCLUSIONS: It is reported that color determination methods based on image processing of photographs taken with iPhone mobile phones could potentially gain an advantageous position in routine clinical practice, as compared to spectrophotometry.

Effect of Additive and Subtractive Coping Production Techniques on Retention and Marginal Fit of Implant Supported Crowns.

This study investigated the marginal and internal fit and retention of crowns fabricated using 4 different castable pattern production methods, namely plastic burn out coping, computer-aided design and computer-aided manufacturing (CAD-CAM) milled (CAD-CAM-M), CAD-CAM additive (CAD-CAM-A), and conventional. This study consisted of 5 groups including 2 different brands of burn out coping groups (Burn out-Straumann [Burn out-S] group and Burn out-Implance [Burn out-I] group), the CAD-CAM-M group, the CAD-CAM-A group, and the conventional group. A total of 50 metal crown copings were produced in each group with 10 metal crown copings. The marginal gap of the specimens was measured twice-both before and after the cementation and thermocycling processes using a stereomicroscope. A total of 5 specimens were selected randomly-1 from each group for scanning electron microscopy analysis and sectioned longitudinally. The pull-out test was performed on the remaining 45 specimens. The lowest marginal gap value was observed in the Burn out-S group before and after cementation with 88.54-97.48 µm, respectively, while the highest marginal gap was observed in the conventional group (186.27-200.58 µm). Implant systems did not significantly affect the marginal gap values (P > .05). Marginal gap values increased significantly after cementation and thermal cycling in all the groups (P < .0001). The highest retention value was measured in the Burn out-S group while the lowest in the CAD-CAM-A group. The highest occlusal cement gap values were observed in the coping groups (Burn out-S and Burn out-I groups), and the lowest in the conventional group in the scanning electron microscopy analysis. The marginal fit and retention values of the prefabricated plastic burn out coping technique was superior when compared with the other techniques, providing that internal fit was superior with the conventional technique.

Custom-Made Root Analog Immediate Dental Implants: A Prospective Clinical Study with 1-Year Follow-up.

PURPOSE: To compare three different types of custom-made root-analog immediate (RAI) dental implants. MATERIALS AND METHODS: Patients with fractured and/or nonrestorable teeth with uncompromised periodontal ligaments were included in the study. The exclusion criteria were as follows: any uncontrolled systemic disease, bruxism, poor oral hygiene, active periodontal disease, and/or chronic marginal periodontitis. CBCT scans of the teeth were taken, and the datasets were used to reconstruct 3D models that were transferred to 3D modeling software to design the RAIs. Group 1 (GR1) consisted of zirconia RAIs manufactured using a computer numerical control (CNC) machine, group 2 (GR2) consisted of titanium RAIs formed by using a CNC machine, and group 3 (GR3) consisted of titanium RAIs manufactured by using direct laser metal sintering (DLMS) technology, all of which were placed immediately after tooth extraction. Primary stability was measured by using Periotest M. Metal-ceramic single crowns were cemented 3 months later. All implants were evaluated clinically and radiologically 1 year after implant placement. RESULTS: A total of 51 patients (18 men, 33 women) aged between 18 and 66 years (average 34.2 years) were included in the study. In 4 patients, RAIs could not be placed due to the lack of primary stability, and they were excluded. In the remaining 47 patients, the custom-made RAIs (GR1: n = 21, GR2: n = 17, GR3: n = 18, total: n = 56) were placed into fresh extraction sockets immediately after tooth extraction for each patient. Primary stability was achieved. Periotest values (PTV) were between -1.4 and -6.2 (mean -3.3). The mean initial PTV (PTV0) was -2.3 ± 1.8 for the failed implants and -4.5 ± 0.8 for the surviving implants. PTV0 was an independent risk factor (HR 3.61, 95% CI: 1.56-8.35, P = .004) for survival rate, which was 33.3%, 70.6%, and 44.4% for GR1, GR2, and GR3, respectively. The overall survival rate was 48.2%. There was no significant difference between the groups regarding the probability of survival (P = .051). The survival rate was significantly lower for anterior RAIs (P < .001). Clinically healthy gingival margins were observed without any signs of periodontitis or implant mobility, and the mean PTV was -4.0 ± 1.9 in surviving implants, whereas the mean marginal bone loss was 1.3 ± 0.6 mm (median, 0.8; 95% CI: 0.1-3.4) at the 1-year follow-up. CONCLUSION: This study was the first attempt to compare different RAI manufacturing techniques and biomaterials in the literature. Although the probability of survival was not statistically significant between the groups, the survival rate in GR2 was higher than in the other two groups. Nevertheless, the overall survival rate was significantly lower (48.2%) than in the previous reports. Primary stability was an independent risk factor for failure. Further studies with the minimized variables between groups should be designed for precise results.

Does abutment preparation affect abutment screw joint stability? An in vitro study.

STATEMENT OF PROBLEM: Whether preparation of an implant abutment decreases the stability of the abutment screw joint is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the abutment preparation in laboratory conditions on the reverse torque value (RTV) of the abutment screw. MATERIAL AND METHODS: Sixty implants, implant analogs, and abutments obtained from 2 different manufacturers were used in the present study and divided into 2 groups (groups B and N) according to the manufacturer. Each group was then divided into 3 subgroups (n=10) according to the remaining wall thickness (control, 0.4 mm, 0.6 mm). All abutments were tightened to analogs with 15 Ncm, and standardized preparation was made with a custom-designed copy-milling system. All abutments were tightened to the implants with 30 Ncm, and then, the abutment screws were removed and RTVs were recorded. Subgroups were analyzed by using 1-way ANOVA (α=.05), and the independent-sample t test was used to compare groups. Relationships between categorical variables were analyzed by chi-square tests. One abutment screw from each subgroup was randomly selected and analyzed by using a scanning electron microscope. RESULTS: A statistically significant difference was found between RTVs of different manufacturers (group B=28.2 ±1.2 Ncm, group N=25.9 ±1.4 Ncm; P<.005). In group N, there was a significant difference among subgroups, control (26.7 ±1.4 Ncm), and 0.6-mm wall thickness (24.8 ±0.8 Ncm) (P<.05). A statistically significant relationship was found between preparation and RTV for the NucleOSS only (P<.05) and between manufacturer and RTV (P<.001). Scanning electron microscopy evaluations identified different screw head and thread designs. CONCLUSIONS: The abutment screw joint stability of the BioHorizons implant was not affected by abutment preparation.

Effect of Surface Modifications of Abutment Screws on Reverse Torque Values: An In Vitro Study.

PURPOSE: To investigate the reverse torque values of abutment screws subjected to various surface modifications. MATERIALS AND METHODS: Sixty abutment screws were divided into two groups of 30 each: with thermomechanical cycling (240,000 cycles) and without thermomechanical cycling. Each group was then divided into three subgroups according to surface treatment: nontreated (NT, n = 10); anodic oxidation (AO, n = 10); and diamond-like carbon (DLC) coating (DLC, n = 10). All abutment screws were tightened to 30 Ncm using a digital torque meter. The reverse torque values of the abutment screws with and without thermomechanical cycling were then measured. The percentage of deviation (PERDEV) for reverse torque values was calculated. Two-way analysis of variance followed by Tukey Honest Significant Difference test were used for intergroup comparisons. RESULTS: Significant differences were found among the PERDEV values of the groups based on thermomechanical cycling and surface treatment (P < .001 for each). A significant interaction was found between surface treatment and thermomechanical cycling (P < .001). CONCLUSION: Reverse torque values of abutment screws were found to be higher after surface treatments. The abutment screws with AO exhibited the lowest torque value loss in groups with and without thermomechanical cycling.

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 (α=.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.

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 (α=.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.

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.

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.

Vertical ridge augmentation using sandwich osteotomy: 2 case reports.

The placement of dental implants in atrophic jaws is a challenging procedure due to inadequate bone quantity. This anatomic limitation can be overcome by various treatment methods such as onlay bone graft, inlay bone graft (known as sandwich osteotomy), and distraction osteogenesis. Two female patients with complaints of atrophic mandible were included in this study. Both patients were treated with a segmental mandibular sandwich osteotomy with interpositional grafts. This is called a sandwich osteotomy technique because a section of the jaw bone is separated from the main part and a bone graft is inserted between the 2 parts. The postoperative period was uneventful, and sufficient bone gain was obtained in both patients. Sandwich osteotomy is an effective technique to gain vertical bone height in atrophic jaws.

Cytotoxicity testing of temporary luting cements with two- and three-dimensional cultures of bovine dental pulp-derived cells.

This study evaluated the cytotoxicity of eugenol-containing and eugenol-free temporary luting cements. For cytotoxicity testing, bovine pulp-derived cells transfected with Simian virus 40 Large T antigen were exposed to extracts of eugenol-containing (Rely X Temp E) and eugenol-free (Provicol, PreVISION CEM, and Rely X Temp NE) temporary luting cements for 24 h. The cytotoxicity of the same materials was also evaluated in a dentin barrier test device using three-dimensional cell cultures of bovine pulp-derived cells. The results of the cytotoxicity studies with two-dimensional cultures of bovine dental pulp-derived cells revealed that cell survival with the extracts of Rely X Temp E, Provicol, PreVISION CEM, and Rely X Temp NE was 89.1%, 84.9%, 92.3%, and 66.8%, respectively. Rely X Temp NE and Provicol showed cytotoxic effects on bovine dental pulp-derived cells (P < 0.05). The results of the dentin barrier test revealed that cell survival with the above-mentioned temporary cement was 101.5%, 91.9%, 93.5%, and 90.6%, respectively. None of the temporary luting cements significantly reduced cell survival compared with the negative control in the dentin barrier test (P > 0.05). Biologically active materials released from temporary luting cements may not influence the dentine-pulp complex if the residual dentine layer is at least 0.5 mm thick.

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.

Prosthetic rehabilitation of velopharyngeal insufficiency: pharyngeal obturator prostheses with different retention mechanisms.

Pharyngeal obturator prostheses restore the congenital or acquired defects of the soft palate and allow adequate closure of palatopharyngeal sphincter. Two patients with soft palate defect and subsequent velopharyngeal insufficiency were rehabilitated using pharyngeal obturator prostheses which had different retention mechanisms. Since it is necessary for swallowing and intelligible speech, the patients were examined in terms of adequate velopharyngeal closure after prosthetic treatment. The results were satisfying for both the patients and physicians.

An alternative method for constructing an obturator prosthesis for a patient with a bilateral cleft lip and palate: a clinical report.

UNLABELLED: The design of esthetic and effective dental prostheses for bilateral cleft lip and palate patients is a challenge for prosthodontists because the prostheses must serve more than one purpose. The goals to be attained by prosthetic intervention are preventing food and liquid leakage into the nose, improving speech intelligibility, a more esthetic appearance, and achieving the general satisfaction of the patient. The framework design of the obturator prosthesis is of great strategic importance for patients with a cleft lip and palate. The reduction in the mass of the obturator prosthesis increases stabilization and retention and also contributes to an easier adaptation to the prosthetic restoration. In this report, a 22-year-old woman was successfully treated with a fixed partial denture and a bar-retained obturator with palatal coverage. CLINICAL SIGNIFICANCE: The design of an obturator prosthesis for cleft lip and palate patients is an important stage in terms of ensuring esthetic restoration and patient comfort. This article describes an esthetic and functional design for such a device using a fixed partial denture and a bar-retained obturator.

Custom-made Gold Implant for Management of Lagophthalmos: A Case Report.

Lagophthalmos is defined as the inability to close the eyelids completely. This situation may lead to corneal problems such as epithelial defects, stromal thinning, exposure keratitis, bacterial infection, perforation, and blindness. A patient with lagophthalmos underwent insertion of a custom-made gold weight implant. After implantation, the patient was able to close her eye and expressed high cosmetic and aesthetic results. Fabrication of gold weight implant by the means of a rolling machine is an effective and easy way and should be considered in the management of lagophthalmos.

The evaluation of water sorption/solubility on various acrylic resins.

OBJECTIVES: The absorption of water by acrylic resins is a phenomenon of considerable importance since it is accompanied by dimensional changes, a further undesirable effect of absorbed water in acrylic resins to reduce the tensile strength of the material. Solubility is also an important property because it represents the mass of soluble materials from the polymers. METHODS: Ten acrylic resin-based materials were evaluated: two heat cure acrylic resins (De Trey QC-20, Meliodent Heat Cure) and eight self cure acrylic resins (Meliodent Cold, Akrileks, Akribel, Akribel Transparent, Vertex Trayplast, Formatray, Dentalon Plus, Palavit G). To evaluate water sorption and water solubility, thirty square-shaped specimens (20x20x1.5 mm) were fabricated from the wax specimens. One way ANOVA test, Tukey test and Pearson correlation coefficient performed for data. RESULTS: Water sorption mean values varied from 11.33+/-0.33 to 30.46+/-0.55 mug/mm(3). Water solubility mean values varied from -0.05+/-0.23 to 3.69+/-0.12 mug/mm(3). There was statistically significant difference between mean values of the materials (P<.05). There was no linear correlation between sorption and solubility values. CONCLUSIONS: The results of the water sorption and water solubility values of both self-cured and heat-cured acrylic resins were in accordance with the ISO specification. No correlation found between water sorption and water solubility values.