Evaluation of gingival porcelains: Color change and surface properties.

PURPOSE: This in vitro study aimed to evaluate the effect of thermal cycling (TC) on the color stability, translucency, and surface roughness of two different gingival porcelain materials. MATERIALS AND METHODS: The gingival porcelains IPS e.max Ceram Gingiva (Ceram) and IPS InLine Gingiva (InLine) were tested. A total of 66 disc-shaped specimens were prepared and glazed using porcelain powders of G1, G3, and G5 colors. The samples were divided into two porcelain groups by their types and into three subgroups (n11) by their colors. Thermal cycling was performed at 6000 cycles simulating an oral environment of 5 years. The color and surface roughness measurements of the samples were made before and after the thermal cycling. Color measurements were made with a spectrophotometer. Surface roughness (mean surface roughness [Ra; µm]) was measured using a contact profilometer. Data before thermal cycling were evaluated using the Kruskal-Wallis test followed by the Dunn Bonferonni paired comparison test. Two-way ANOVA with repeated measurements and a pairwise comparison test with Bonferroni correction were used to evaluate the change in roughness and translucency parameter (TP) data between groups due to thermal cycling. RESULTS: The color change was below the clinically perceptible color change threshold (∆E00 = 2.1) in all groups after thermal cycling. However, all materials had significantly increased roughness (p < 0.05). An increase in roughness was detected in the Ceram group and was higher than that in the InLine group. The change in the translucency parameters of the samples after thermal cycling was not statistically significant; a small increase was observed in all groups. The highest translucency values ​​were seen in the G1, G3, and G5 colors. CONCLUSIONS: Thermal cycling caused a significant increase in the roughness values ​​(Ra) of all materials and a minimal increase in their translucency. The color change of gingival porcelains after thermal cycling was less than the clinically perceptible threshold.

Future expectations, career choices and related factors among dental students: A cross-sectional study.

Purpose: The aim of this study was to determine descriptive characteristics of dental students, to investigate their professional expectations, career decision criteria, and related factors; to examine how (if any) seniority in school affects these. Subjects and methods: During the period of 2018-2019, all 1-5 grade students (n = 754) of Hacettepe University Dental School were invited to participate and those who accepted had filled under observation a standard questionnaire form of 35 questions (83.4%). In the analysis of the data, descriptive statistics, chi-square, Student's t-test and ANOVA and Odds ratio methods were used. Results: In this cross-sectional study, 66% of the group were female, age range was 18-30 (mean±SD= 21.2 ± 1.7). The most common reasons for choosing dentistry were "financial benefits", "job security" and "professional status". "Undertake specialist training" (80.2%) was the most common short-term expectation after graduation; two most common long-term expectations were "having a private clinic" (57.9%) and "completing specialization training" (56.0%). The most important factors affecting the post-graduation working plans were work-life balance and economic stability. Conclusion: It is recommended to provide adequate counseling and guidance to students about potential career paths to maximize a balanced and widely accessible oral health service delivery across the country with more motivated dentists. Qualitative research may improve our understanding of how dental education can be improved to fulfill students' expectations from school, and to motivate dental students towards general practitioning in the future.

Marginal Fit of All-Ceramic Crowns Before and After Cementation: An In Vitro Study.

The marginal integrity of all-ceramic crowns for anterior and posterior teeth were evaluated. A total of 60 ceramic crowns (In-Ceram Alumina, IPS e.max Press, and Lava) were fabricated for the epoxy resin maxillary first central incisor and first molar and divided into three groups (n = 20). The crowns were measured at the facial, lingual, mesial, and distal finish lines (52 points) before and after cementation using scanning electron microscopy. The results were analyzed using one-way analysis of variance, paired samples t test, and independent t test. The mean values of marginal gaps were within acceptable clinical limits before and after cementation. The values of the anterior crowns at the buccal finish line were higher than those at the proximal finish line areas (P < .05). However, these were insignificant at four measurement areas for posterior crowns (P > .05). Marginal gaps of crowns at the anterior teeth were higher than at the posterior teeth for all groups.

Comparative audiometric evaluation of temporomandibular disorder patients with otological symptoms.

OBJECTIVES: The purpose of this study was to assess the audiological status of temporomandibular disorder (TMD) patients with otological symptoms and to make comparisons with that of a control group of subjects without TMD and otological symptoms. METHODS: 25 TMD patients with otological symptoms and 20 age and gender matched controls, 45 subjects in total, were included in the study. All subjects underwent a series of audiological tests that included pure-tone audiometry, impedance test and reflex tympanometry. The audiological parameters recorded in the two groups were compared statistically by means of unpaired t tests and corrected according to Bonferroni in the case of repeated tests. RESULTS: The pure-tone thresholds at frequencies 125, 250, 500Hz, and 6kHz showed significant differences between the TMD patients and control subjects after the Bonferroni correction (p<0.007). Compliance peaks demonstrated significant differences when the TMD and control groups were compared (p<0.05). CONCLUSIONS: The findings indicate that TMD patients with otological complaints have hearing impairment at low frequencies and also perhaps, at high frequencies.

Evaluation of shear and tensile bond strength between dentin and ceramics using dual-polymerizing resin cements.

STATEMENT OF PROBLEM: The applications of dual-polymerizing resin cements for all-ceramic restorations have considerably increased. For a successful clinical outcome, the luting agent should have high bond strength, not only to the ceramic surface, but also to the tooth surface. PURPOSE: The purpose of this study was to examine shear (S) and tensile (T) bond strengths between 2 all-ceramic systems and human dentin using 3 dual-polymerizing resin cements. MATERIAL AND METHODS: The buccal surfaces of 120 freshly extracted human third molars were ground flat, parallel to the long axis. Sixty specimens were prepared from each of 2 all-ceramic systems (IPS Empress 2 (E) and Cergo Pressable Ceramic (C)). Twenty specimens were luted with each of the following resin cements: Nexus 2 (N) with Self-Etch Primer, Duo-Link (D), and Variolink II (V), with their respective bonding systems. All specimens were immersed in water at 37 degrees C for 1 week, before being thermal cycled for 500 cycles in 5 degrees C and 55 degrees C water. Shear (S) and tensile (T) bond strength tests were applied to 10 specimens from each group. Fractured surfaces were inspected by scanning electron microscopy (SEM). Statistical analyses were performed using nonparametric 1-way ANOVA (Kruskal-Wallis) followed by Duncan's multiple range tests for post hoc comparison and Mann-Whitney U test for 2 ceramic systems (alpha=.05). RESULTS: Significant differences were observed in shear and tensile bond strength values of the adhesive systems used (P<.05). Duo-Link showed the highest mean bond strength values, whereas Nexus 2 revealed lower shear and tensile bond strength values. Fracture modes were hybrid at the dentin interface and/or cohesive in dentin. CONCLUSIONS: Cementing agents/adhesive systems may influence the bond to dental hard tissues. Dual-polymerizing activators may have a negative effect on polymerization of the bonding agent.

Rehabilitation of a marginal mandibulectomy patient using a modified neutral zone technique: a case report.

Anterior edentulous areas usually display unusual soft tissue configurations and compromised bone support in patients with marginal mandibulectomy. There are several treatment modalities for these patients. A removable partial denture may be the treatment of choice. Maximum stability of the partial denture base for mandibulectomy patients may be accomplished by the application of the neutral zone concept, which helps providing stability to the base. This case report describes the fabrication of a removable partial denture for a patient with marginal mandibulectomy using a modified neutral zone technique.

Rehabilitation of a marginal mandibulectomy patient using a modified neutral zone technique: a case report

Anterior edentulous areas usually display unusual soft tissue configurations and compromised bone support in patients with marginal mandibulectomy. There are several treatment modalities for these patients. A removable partial denture may be the treatment of choice. Maximum stability of the partial denture base for mandibulectomy patients may be accomplished by the application of the neutral zone concept, which helps providing stability to the base. This case report describes the fabrication of a removable partial denture for a patient with marginal mandibulectomy using a modified neutral zone technique.

Areas anteriores edêntulas apresentam configurações incomuns de tecido mole e suporte ósseo comprometido em pacientes submetidos a mandibulectomia marginal. Há diversas modalidades de tratamento para estes pacientes. A instalação de uma prótese parcial removível pode ser o tratamento de escolha. Máxima estabilidade da base da prótese parcial para pacientes submetidos a mandibulectomia pode ser obtida pela aplicação do conceito da zona neutra, o que auxilia na estabilização da base. Este relato de caso descreve a fabricação de uma prótese parcial removível em um paciente com mandibulectomia marginal utilizando uma modificação da técnica da zona neutra.

The fabrication of cast metal guidance flange prostheses for a patient with segmental mandibulectomy: a clinical report.

Deviation of the mandible toward the resected side is dependent upon the amount of soft and hard tissue resected, the method of surgical site closure, the degree of impaired tongue function, the presence and condition of teeth, the loss of proprioceptive sense of occlusion, and the timing of prosthodontic therapy. Prosthodontic therapy combined with physical therapy may be beneficial for reducing and minimizing mandibular deviation. This clinical report describes the fabrication of cast metal guidance flange prostheses. The supporting flanges assist in controlling mandibular deviation and coordinate masticatory movements for a patient following a segmental mandibulectomy.

Analysis of strain around endosseous dental implants opposing natural teeth or implants.

STATEMENT OF PROBLEM: Natural teeth and implants have different force transmission characteristics to bone. PURPOSE: The purpose of this study was to compare strains induced around a natural tooth opposing an implant with strains around occluding implants under static and dynamic loads. MATERIAL AND METHODS: Occlusion was created between a natural molar tooth and an implant in 1 side, and 2 implants in the contralateral side of acrylic resin models of both jaws. Strain-gauges were bonded around the neck of the natural tooth and implants, and strains were measured under 75 N and 100 N static axial and lateral dynamic loads in separate load situations using a data acquisition system at sample rate of 1000 Hz. The strain data of the natural tooth and implants were compared for each load by Kruskal-Wallis testing followed by the multiple comparison test (alpha=.05). RESULTS: Compressive strains were induced around natural tooth and implants as a result of static axial loading, whereas combinations of compressive and tensile strains were observed during lateral dynamic loading. Strains around the natural tooth were significantly lower than the opposing implant and occluding implants in the contralateral side for most regions under all loading conditions ( P <.05). There was a general tendency for increased strains around the implant opposing natural tooth under higher loads and particularly under lateral dynamic loading ( P <.05). CONCLUSION: Under static and dynamic loads, strain magnitudes around a natural tooth were significantly lower than that of an opposing implant and occluding implants in the contralateral side.