Surface roughness and wear behavior of occlusal splint materials made of contemporary and high-performance polymers.

With the development of a digital technology of computer-assisted manufacturing (CAD/CAM) and new age materials, the use of new types of occlusal splint is to consider. The aim of the present study was to evaluate the surface roughness (Ra) and wear behavior of different CAD/CAM materials against enamel antagonist through a simulated chewing test. A total of 75 specimens made from ethylene vinyl acetate (EVA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyetheretherketone (PEEK), and polyethyleneterephthalate (PETG) as a control were polished to evaluate the Ra before loading by optical profilometry and further analyzed by scanning electron microscopy (SEM). Specimens of each group were subjected to thermomechanical fatigue loading in a chewing simulator (60000 cycles at 49 N with 5-55 °C thermocycling). The wear volume loss and change in Ra of each specimen after the simulated chewing were analyzed. One-way ANOVA, paired samples t test, and Pearson correlation analysis were performed for statistical analyzes. The result showed that the volume loss and Ra varied among the materials tested. EVA exhibited the greatest amount of Ra and volume loss (p < 0.001), while PEEK had the lowest values for both (p < 0.001). In terms of volume loss, there was no significant difference between PC and PMMA (p > 0.05). SEM investigations revealed different wear behaviors, especially in EVA. As PEEK showed significantly more favorable results, PEEK splints should be considered as a new therapeutic option for occlusal splint.

In vitro study of effects of aging and processing conditions on colour change in maxillofacial silicone elastomers.

BACKGROUND: The inherent colour change in maxillofacial silicone elastomers becomes perceptible 6-12 months after fabrication. Determining the factors that accelerate the degradation of the prosthesis can help the clinicians increase its life span. Therefore, the aim of the study was to investigate the effect of time passage, processing temperature, and molding-stone colour on the colour change of maxillofacial silicone elastomers after darkroom storage for 6000 h. METHODS: A total of ten study molds, each incorporating ten specimen gaps were fabricated using five different colors of dental stones. The gaps were filled with coloured Cosmesil M511 maxillofacial silicone elastomer. Five of the study molds, one of each stone color, were processed at room temperature (25 °C) for 24 h while the remainder were vulcanized at 100 °C for 1 h. Two stainless-steel molds were also fabricated to obtain a total of twenty control-group specimens of the same dimensions that were processed under the same conditions as the study molds. Colour measurements of the vulcanized silicone samples were performed using a Konica Minolta spectrophotometer. Initial measurements were obtained after the blocks were removed from the molds and the final measurements were recorded 6000 h after storage in the dark at 25 °C and 40% relative humidity. The CIEDE2000 colour-difference formula was used to measure the changes in the colour. One-way and two-way ANOVA, and an independent-sample t-test were used for statistical assessments. RESULTS: For every group, the colour change exceeded the perceptible thresholds. Thus, either the vulcanization temperature or the colour of the molding stone has a significant effect on the colour change over time. Those samples vulcanized in green and white molding stones at 100 °C exhibited a significantly higher ∆L*, ∆a*, and ∆b* values relative to the samples vulcanized at room temperature. CONCLUSION: The molding-stone colour and vulcanization temperature both affect the degree of colour change after storage in a dark environment. The L*, a*, and b* values for the maxillofacial silicone elastomers are influenced by the direction of the increase or decrease according to the selected colour. This effect varies as the temperature increases.

Management of pain in TMD patients: Bio-oxidative ozone therapy versus occlusal splints.

OBJECTIVE: To compare the effects of bio-oxidative ozone application with occlusal splints in temporomandibular disorder (TMD) patients with pain. METHODS: Forty participants were selected after the diagnosis of TMD and randomly divided into two groups: ozone group (OG, n = 20) and occlusal splint group (OCSG, n = 20). Ozone was applied to patients three times per week, for a total of six sessions. Patients in the OCSG were instructed to use occlusal splints every night over a period of four weeks. RESULTS: Mandibular movements showed significant differences for the time factor in OG and OCSG. Pressure pain thresholds of the temporal and masseter muscles at follow-up were significantly higher in the OCSG group. Both treatments statistically decreased the visual analog scale (VAS) scores. However, no statistically significant difference was observed between groups after the application of treatments. DISCUSSION: Occlusal splint treatment is still the gold treatment modality for objective pain relief in patients with TMD pain.

Comparing the precision of reproducibility of computer-aided occlusal design to conventional methods.

PURPOSE: Reconstruction of patients' dental occlusion should be performed to fulfill esthetic and functional demands. These applied restorations should be in harmony with the existing occlusion and should not have any negative effects on intraoral dynamics. The aim of this clinical study is to compare the accuracy of the occlusal design shaped by conventional Wax Up methods and computer-aided design (CAD) regarding their similarity to the natural tooth morphology. METHODS: Impressions of 10 caries-free jaws were taken, and the resulting gypsum casts were scanned with a laboratory scanner. Preparations for all-ceramic full crowns were performed on second premolars and second molars. Occlusal design of 40, 3-member fixed partial dentures (FPD) were obtained with two different methods 10 FPD was designed with conventional wax up technique (Wax Up), 30 design was performed with CAD Dental wings open system (DWOS) software using three different anatomy libraries (Dental Wings (DW), Merz, Vita). The data of the bridges in the STereo-Lithography Interface Format (STL) was compared with the pre-cut data, which was regarded as a reference in terms of accuracy in the Atos so high end 3D digitizer. RESULTS: According to the results of Kruskal-Wallis test, there was no statistical difference between the Wax Up, Vita, Merz and Dental Wings groups (p>0.05) when compared to the natural teeth. The main difference between all four groups and natural surface was 550±130µm. CONCLUSIONS: Occlusal design produced by conventional techniques and CAM DWOS system compared to natural tooth morphology showed no statistically significant difference.

Predictors of obturator functioning and satisfaction in Turkish patients using an obturator prosthesis after maxillectomy.

OBJECTIVE: The aim of this study was to determine the sociodemographic, behavioral, and clinical factors affecting obturator function and satisfaction using the obturator functioning scale (OFS) in maxillectomy patients rehabilitated with obturator prostheses. STUDY DESIGN: The study sample consisted of 41 maxillectomy patients. The OFS was translated into Turkish and adapted for assessing obturator functioning and patient satisfaction among Turkish patients. Data were collected from patients' medical records and self-completed questionnaires, including the Turkish version of the OFS, sociodemographic and behavioral characteristics. Descriptive statistics, Mann-Whitney U test, Spearman's correlation coefficient, and backward stepwise multiple linear regression were used for data analysis. RESULTS: Internal consistency (Cronbach's alpha = 0.85) and test-retest reliability (intraclass correlation coefficient = 0.86) were acceptable for the OFS. The most frequently reported problem was "difficulty chewing." Bivariate analysis revealed significant differences in total OFS scores in terms of surgery type, defect size, and education level, except for the other clinical and sociodemographic characteristics and behavioral factors. Education level and surgery type were found to be the most important predictors of patient satisfaction and functioning of the obturator. CONCLUSIONS: The Turkish version of the OFS might be a useful tool for clinicians to identify patients who are at risk for poor functioning of the obturator, lack of satisfaction, and unmet needs.

Effect of dentin pretreatment on shear bond strength of three resin-based luting cements.

PURPOSE: The aims of this study were; to compare the shear bond strength values of resin-based luting cements using etch-and-rinse, self-etching or self-adhesive techniques and to evaluate the effects of pretreatment with 0.2%, and 2% chlorhexidine (CHX) solutions on the bonding stability to dentin. MATERIALS AND METHODS: Ninety specimens were divided into 9 groups of equal sample size (0.2% CHX, 2% CHX and no CHX application groups). Variolink N (multi-step etch-and-rinse technique), Panavia F2.0 (self-etching technique), or RelyX U200 (self-adhesive technique) resin-based luting cement was applied. All specimens were subjected to shear bond strength test (SBS) after bonding procedure. The mode of failure was analyzed by using a stereomicroscope. RESULTS: There were no significant differences among study groups for the dentin treatment factor. However, for luting cement factor, significant differences were found and Variolink N showed the highest SBS values. CONCLUSION: CHX application has no immediate effect on the SBS values of any resin cements. Despite the development of simplified cementation techniques, etch-and-rinse technique is still the most reliable technique because of its high bond strength to dentin.

Prevalence of Candida albicans and Streptococcus aureus on maxillary obturators, maxillary defects and in saliva: A cross-sectional study / Prevalência de Candida albicans e Streptococcus aureus em obturadores superiores, nos defeitos maxilares e na saliva: Um estudo transversal

Objetivo: este estudo investigou a incidência da adesão de Candida albicans e Staphylococcus aureus em próteses superiores obturadoras com materiais de reembasamento macio utilizados por protesistas. Material e Métodos: entre os anos 2013 e 2014, foram avaliados clinicamente, pacientes com defeitos maxilares devido a cirurgia para remoção de tumores e usuários de próteses obturadoras (n = 21, grupo de estudo) e, as consequências microbiológicas foram comparadas com usuários de prótese total superior (n = 21, controle grupo). Os dados foram coletados sobre características demográficas, tipo histológico de câncer, emprego de quimioterapia ou radioterapia, identificação dos materiais reembasamento macio utilizados e métodos de limpeza praticados nas próteses obturadoras e totais. A presença de Candida albicans foi determinada nos materiais de reembasamento macio ou nas superfícies de polimetilmetacrilato e na cavidade bucal e, Staphylococcus aureus na mucosa nasal e na saliva. Os dados foram analisados utilizando os testes Kruskal Wallis, Fisher-Freeman-Halton (p<0,05). Resultados: A maior quantidade de Candida albicans foi encontrada nas superfícies das próteses, na saliva, nos defeitos no palato duro e no material de reembasamento macio definitivo com 90%, 90% e 70%, respectivamente. A maior quantidade de Staphylococcus aureus foi observada na saliva e na cavidade nasal no grupo de material de reembasamento macio definitivo (50%). Conclusão: o curto período de renovação dos materiais de revestimento pode causar menos colonização de Candida albicans e estomatite protética na cavidade bucal. Os pacientes que sofreram maxilectomia foram mais propensos à colonização de Staphylococcus aureus.(AU)

Objective: This study investigated on the incidence of Candida albicans and Staphylococcus aureus adhesion onto maxillary obturator prostheses with soft lining materials placed by prosthodontists. Material and Methods: Between years 2013 and 2014, patients with maxillary defects due to maxillary tumor surgery and acquired obturator prostheses (n = 21, study group) were clinically evaluated and microbiological outcomes were compared with complete maxillary denture wearers (n = 21, control group). Data were collected on demographic features, histological type of cancer, presence of chemotherapy or radiotherapy, identification of soft lining materials used on obturator prostheses, cleansing methods practiced for obturator and maxillary complete prostheses. The presence of Candida albicans was determined on soft lining materials or polymethylmethacrylate surfaces and in the oral cavity, and Staphylococcus aureus in nasal mucosa and saliva. Data were analyzed using Kruskal Wallis, Fisher-Freeman-Halton tests (p<0.05). Results: The highest amount of Candida albicans was found on surfaces of prostheses, in the saliva and on maxillary defects on the hard palate and on definitive soft lining material with 90%, 90%, and 70%, respectively. The highest amount of Staphylococcus aureus was observed in the saliva and nasal cavity in the definitive soft lining material group (50%). Conclusion: Short renewal period of lining materials may cause less Candida albicans colonisation and denture stomatitis in the oral cavity. Patients who have undergone maxillectomy were more prone to Staphylococcus aureus colonisation.(AU)

Oral Rehabilitation of an Osteopetrosis Patient with Osteomyelitis.

Osteopetrosis is a congenital disorder characterized by increasing osteoclastic function resulting in osteomyelitis in the jaws. Orofacial findings in osteopetrosis patients are unerupted, malformed, or delayed teeth and many dental caries due to vulnerable enamel and dentin and osteomyelitis. Many reports have described that maxilla is an uncommon site of occurrence for osteomyelitis due to cortical bone morphology and collateral circulation. This report aims to discuss clinical features and prosthodontic management of a patient with clinical features of adult form of osteopetrosis and osteomyelitis in both jaws. The patient has reported better masticatory and speech efficiency with removable dentures in maxillary and mandibular jaw and also self-esteem improvement and family interaction.

Assessment of the effect of two occlusal concepts for implant-supported fixed prostheses by finite element analysis in patients with bruxism.

The aim of this study was to evaluate the effects of bruxing forces on implants configured under 2 different occlusal schemes by dynamic finite element analysis. A main model consisting of a 5-unit fixed partial denture supported by 3 implants was simulated with bone, implants, and superstructures. All calculations were made individually for each component, namely porcelain crowns, abutments, abutment screws, implants, and bone. Maximum stresses were found in the group-function occlusion. Group-function loading may result excess stresses on the components compared with canine-guidance loading. According to the results of this study, use of canine guidance is encouraged in bruxers with implant-supported prostheses.

Influence of acrylic resin polymerization methods on residual monomer release.

AIM: The aim of this study was to quantify and compare the amount of methyl methacrylate (MMA) monomer released from three different denture base acrylic material processed by different polymerization methods and storage conditions. MATERIALS AND METHODS: Microwave-cured, conventional heat and injection-technique acrylic polymerized materials were stored in neutral (pH = 7) and acidic (pH = 4.5) artificial saliva for 24 hours at the room temperature, separately. The residual MMA content was determined by high performance liquid chromatography (HPLC). RESULTS: The MMA leaching from resins showed that microwave-cured material has lower residual MMA leach compared both conventional and injection-technique on neutral saliva storage conditions. CONCLUSION: The all data's exhibited higher MMA release into an acidic saliva environment than neutral artificial saliva and there were no significant differences between the materials groups on acidic saliva storage conditions. CLINICAL SIGNIFICANCE: Microwave polymerization method might has some advantages on reducing release of MMA concentration and may contributory effect upon polymerization reaction on neutral pH storage condition, therefore methods of polymerization should be considered as amount of monomer release.

Prevalence of bruxism awareness in Istanbul, Turkey.

The reported prevalence of symptoms related to bruxism varies in the general population because of different investigative methodologies, operational definitions, clinical criteria, and samples of population. Awareness of bruxism in the general population is 15% to 23%, however, this rate increases to 50% to 90% in clinical studies. The aim of this study was to investigate the prevalence of self-reported symptoms associated with bruxism in Istanbul, Turkey and to analyze the correlation between bruxism and factors such as age, gender, marital status, and occupation. Seven-hundred-ninety-five (795) adult subjects who resided in the city of Istanbul were interviewed by telephone about their age, gender, marital status, occupation, and description of the prevalence of bruxism awareness. The overall prevalence of clenching teeth was 45.7% and that of grinding teeth was 21.6%. Women responded positively to the questions more often than men. The data showed significant differences between males and females, regarding clenching teeth OR: 1.41 (95% CI: 1.05-1.87), difficulty opening OR: 2.64 (95% CI: 1.63-4.26), headache on awakening OR: 2.28 (95% CI: 1.58-3.27) joint sounds OR: 1.72 (95% CI: 1.24-2.38), sore on awakening OR: 2.97 (95% CI: 1.91-4.61), influence in daily activity (OR: 2.26 CI: 1.38-3.67). Tooth wear in the married group was higher than the single group. Age distribution showed significant differences related to grinding teeth, tooth wear and joint sounds. There were statistically significant differences between bruxism and job categories. As a conclusion, this study suggest an association between bruxism and stressful events such as marital status and job problems.

Applicability of zirconia dental prostheses for metal allergy patients.

The aim of this study was to investigate the applicability of zirconium dioxide (zirconia) as a substitute for metal alloys in a group of metal allergy patients. Fourteen patients (eight women, six men) who had been restored with porcelain-fused-to-metal fixed partial dentures (FPDs) and had exhibited hypersensitivity lesions to dental alloys were enrolled in this study. Patients were previously patch-tested using standard testing substances authorized by the International Contact Dermatitis Research Group. Patients received FPDs with zirconia frameworks and occurrences of oral symptoms were evaluated. No hypersensitivity lesions in the mouth or on the skin were encountered during the follow-up period of 3 years. Zirconia FPDs may be an alternative to porcelain-fused-to-metal FPDs in patients with metal allergies.

Survival and Success of ITI Implants and Prostheses: Retrospective Study of Cases with 5-Year Follow-Up.

OBJECTIVES: The use of osseointegrated implants as an endoestal anchorage device to provide support for dental prostheses is a reliable and widely accepted treatment modality. The purpose of this study was to evaluate the clinical performance of non-submerged implants placed in the maxilla or in the mandible. METHODS: A total of 146 International Team for Implantology (ITI) (Straumann AG, Waldenburg, Switzerland) implants were placed in 42 patients (20 women, 22 men, mean age 42). The cases were examined retrospectively in order to evaluate the clinical efficiency of non-submerged ITI implants and to determine the success rate of implant retained/supported prosthesis after a 5-year period. All implants were assessed clinically and radiographically on a yearly basis. RESULTS: The 5-year cumulative success rates for maxillary and mandibular implants were 91.00% and 97.81%, respectively. The most common prosthetic complication was abutment accompanied by screw loosing (3.42%). Veneering material fracture was documented in only one patient. CONCLUSIONS: Within the limitations of the observation period and sample number, the present findings confirmed sufficient success and survival rates of ITI implants placed in mandible as well as implants placed in the maxilla after a 5-year period.

Patient responses to vacuum formed splints compared to heat cured acrylic splints: pilot study.

OBJECTIVE: Vacuum formed and heat cured acrylic splints have been used in the diagnosis and treatment of temporomandibular disorders. The aim of this study was to evaluate patient's preference to either the vacuum formed or the heat cured acrylic splint. MATERIAL AND METHODS: Twenty patients planned to receive splints were chosen from the dental school. Both types of occlusal splints were fabricated for each of them. Each patient used the splints alternatively on a nightly basis for 3 weeks. After 3 weeks, each patient completed a questionnaire regarding the comfort, fit, retention, occlusal contact, taste, gingival and lip irritation, smoothness and smelling. Statistical analysis was conducted by the MacNemar's Chisquare test. RESULTS: There was no statistical difference in patient's responses to the different splint materials except for the comfort of wearing through the night. CONCLUSION: The vacuum formed and heat cured acrylic splint may be equally worn in patient preference for treatment of temporomandibular disorders.

Estrogen replacement therapy among postmenopausal women and its effects on signs and symptoms of temporomandibular disorders.

The prevalence of temporomandibular disorders (TMD) is about two to five times higher in females than in males. Data for the higher prevalence of TMD in women and prevalence rates peak during the reproductive years and decrease after menopause. This indicated that female sex hormones may play a role in the etiology or maintenance of TMD. The aim of this study was to investigate the relationship between postmenopausal hormone use and TMD in Turkish postmenopausal women. One hundred-eighty (180), postmenopausal women, aged 42-72 years, were examined both clinically and by questionnaire with regard to the signs and symptoms of temporomandibular disorders, general health status and use of postmenopausal hormone replacement therapy in the preceding year. Ninety-one (91) postmenopausal women (50.6%) were on hormone replacement therapy (HRT). The remaining 89 (49.4%) postmenopausal women were not on hormone replacement therapy. There was no significant difference found in the signs and symptoms of TMD between postmenopausal women using hormone therapy and those not using postmenopausal hormones. There was no association between the use of postmenopausal hormones and the signs and symptoms of TMD in this study.

Comparative study of the effect of tube drainage versus methylprednisolone after third molar surgery.

OBJECTIVE: The purpose of this study was to compare the effects of tube drainage versus a single dose of methylprednisolone (MP) on maximal mouth opening, facial swelling, and pain after third molar surgery. STUDY DESIGN: Twenty-two patients requiring extraction of bilaterally impacted mandibular third molars were selected. Each patient had 2 operations. In the first operation, a drainage tube was inserted into the buccal fold after the suture procedure and left there for 3 days. In the second operation 1 month after the first surgery, 1.5 mg/kg intravenous methylprednisolone was administered 1 hour before the surgery. The patients were evaluated by the same person for maximal mouth opening, facial swelling, and pain in the immediate preoperative time point and on the second, fifth, and seventh days after surgery. RESULTS: There was a statistically significant difference in mouth opening on fifth and seventh days but none in facial swelling and pain between MP group and drain group. CONCLUSION: We conclude that the use of a drain or methylprednisolone is useful in reducing postoperative discomfort after third molar surgery.