Purpose: Based on the findings from available research on bruxism and prosthetic treatment published in the dental literature, an attempt was made to draw conclusions about the existence of a possible relationship between the two, and its clinical relevance.
Study selection: MEDLINE/PubMed searches were conducted using the terms ‘bruxism’ and ‘prosthetic treatment’, as well as combinations of these and related terms. The few studies judged to be relevant were critically reviewed, in addition to papers found during an additional manual search of reference lists within selected articles.
Results: Bruxism is a common parafunctional habit, occurring both during sleep and wakefulness. Usually it causes few serious effects, but can do so in some patients. The etiology is multifactorial. There is no known treatment to stop bruxism, including prosthetic treatment. The role of bruxism in the process of tooth wear is unclear, but it is not considered a major cause. As informed by the present critical review, the relationship between bruxism and prosthetic treatment is one that relates mainly to the effect of the former on the latter.
Conclusions: Bruxism may be included among the risk factors, and is associated with increased mechanical and/or technical complications in prosthodontic rehabilitation, although it seems not to affect implant survival. When prosthetic intervention is indicated in a patient with bruxism, efforts should be made to reduce the effects of likely heavy occlusal loading on all the components that contribute to prosthetic structural integrity. Failure to do so may indicate earlier failure than is the norm.

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Purpose: Common reasons for tooth extractions include periodontal disease, dental caries and root fracture. The purpose of this study was to investigate the association of tooth loss after prosthetic treatment, particularly incidences due to root fracture, which occur frequently and are difficult to prevent.
Methods: Data were collected from consecutively selected medical records of patients taken over 3 years after their initial visit to Osaka University Dental Hospital. Collected data included (1) age and gender, (2) number of teeth at the initial visit and number of extracted teeth, (3) reasons for extraction, (4) restored with or without a post and (5) abutment of removable partial dentures (RPDs). A Chi-squared test was applied among the reasons for extraction, whether the tooth was restored with a post or not and clasped or not. A logistic regression analysis was used to determine the associations of root fracture with the patient data.
Results: This study included 101 patients (296 extracted teeth). The reasons for extraction included periodontal disease (64.6%), caries (25.3%) and root fracture (10.1%). The percentage of root fracture was significantly higher for female than male, for restored teeth with posts than without posts and for abutment of RPDs than for non-abutment teeth. Logistic regressions showed that root fractures were significantly associated with gender and abutments.
Conclusion: The most frequently stated reasons for tooth extraction after prosthetic treatment were periodontal disease and dental caries, followed by root fracture. Root fractures were significantly associated with gender and abutment teeth of RPDs.

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Purpose: The purpose of this retrospective study was to assess the implant survival rate and the risk factors associated with implant failure in patients who had undergone immediate implant restoration.
Materials and methods: We performed a retrospective review and an outcome assessment of all patients who received immediate implant restoration between 2000 and 2010 in our department at Tokushima University Hospital. The patients were divided into groups on the basis of the predictor variables: age, gender, implant location, and number of implants per jaw. The cumulative implant survival rate in the paired groups was determined by using Kaplan–Meier analysis and the log-rank test. Cox proportional hazards model was subsequently used to identify exposures associated with implant failure.
Results: Using the Kaplan–Meier method, the survival rates at 1, 3, and 9 years were calculated to be 98.8%, 98.0%, and 94.7%, respectively. No statistically significant association was observed between the implant survival rates and the predictor variables: gender, age, location, and number of implants.
Conclusions: Immediate implant restoration is a reliable prosthetic procedure with an acceptable survival rate compared to the conventional implant procedure.

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Purpose: The purpose of this study was to investigate the differences between Rocatec (as surface treatment) and #600 polishing (as control) on shear bond strength of layering porcelain and hybrid composite to zirconium dioxide ceramics.
Methods: Manufactured zirconia blocks used in this study were yttrium partially stabilized zirconia (YTZ^®), and veneering materials were NobelRondo Zirconia Dentin A2 High Value (NZR) and Estenia C&B (ES). Total 48 zirconia blocks were fabricated (10 mm × 10 mm × 20 mm). The blocks of 24 each were treated by Rocatec and #600 paper, respectively. Surface treated zirconia blocks were divided into two groups, according to veneering materials of NZR and ES. NZR was fired and ES was polymerized to zirconia. The fabricated specimen was fixed to mounting jig and applied shear force using the universal testing machine at a crosshead speed of 0.5 mm/min. All results were statistically analyzed by two-way ANOVA and Tukey's test. EPMA analysis and SPM analysis of specimen interface were carried out.
Results: Mean shear bond strength of each condition was: NZR/#600; 23.3 (S.D. ±7.0) MPa, NZR/Rocatec; 26.9 (S.D. ±7.0) MPa, ES/#600; 10.7 (S.D. ± 2.4) MPa, ES/Rocatec; 12.5 (S.D. ± 0.8) MPa.
Conclusions: From the results of this study, shear bond strength of layering porcelain to zirconia was higher than that of restorative hybrid resin. However the more study will be needed, the appropriate choice of materials became the gides to the expansion of the applied cases of metal-free prothesis.

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Purpose: This study evaluated the relationship between anxiety levels and severity degrees of chronic orofacial pain of temporomandibular disorder in brazilian university students.
Methods: 150 volunteers (117 men and 33 women), with age ranging from 17 to 30 years, were subjects to this study. Spielberger's trait–state anxiety inventory was used to evaluate trait and state anxiety of the students, while examination for chronic orofacial pain was performed in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Association between anxiety levels and severity degrees of chronic orofacial pain was tested using the Chi-square test. The significance level was set at p < .05.
Results: The results showed that 32.7% (n = 49) of the subjects exhibited TMD, and the intensity of chronic orofacial pain was classified as degree 1 in 85.7% (n = 42) and as degree 2 in 14.3% (n = 7) of them. Based on the results of the Spielberger's trait–state anxiety inventory, the majority of the students had moderate anxiety (48.6% and 48.1%, respectively). The correlation between trait-anxiety levels and chronic orofacial pain degrees was significant and positive (p < .05). However, no significant correlation was found to state-anxiety levels and chronic orofacial pain degrees (p > .05).
Conclusion: It was concluded that chronic orofacial pain of TMD could be present in university students and anxiety may be related.

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Purpose: We investigated the relationship between clenching occurring during the day under natural conditions and psychological attributes.
Method: Subjects were 37 dentistry students and staff (14 women, 23 men; mean age 27.4 ± 4.7 years). A portable EMG recording device was used to record muscle activity in the temporal muscles for a continuous 5-h period under subjects’ natural conditions, including having lunch. Clenching was identified by electromyography, and subjects were categorized into clenching and non-clenching groups. Psychological testing was performed during the same period using the Modified Taylor Manifest Anxiety Scale (MAS), the Self-rating Depression Scale (SDS), and the Cornell Medical Index (CMI), and the psychological attributes of clenching and non-clenching groups were compared.
Results: Of the 37 subjects, 23 were assigned to the clenching group and 14 to the non-clenching group. Thirteen of the 23 subjects of the clenching group and none of the 14 subjects of the non-clenching group were determined to have psychological problems according to the MAS, with a significant difference observed between the clenching and non-clenching groups in terms of anxious tendency (p < 0.001; Fisher's exact test). Total muscle activity in the clenching group, excluding eating and talking, was 3.5 times greater compared with the non-clenching group, and a significant difference between the groups was observed (p < 0.05; Mann–Whitney U-test).
Conclusions: Daytime clenching was shown to be associated with anxious tendency. Total muscle activity in the clenching group was 3.5 times greater compared with the non-clenching group.

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Venous blood is currently the most common source of DNA for gene polymorphism screening; however, blood sampling is invasive and difficult to perform in general dental treatment. Buccal mucosa samples provide an alternative source of DNA, but it is frequently difficult to effectively amplify the DNA owing to the small amounts of sample material obtained. This study was performed to establish a method for performing total genomic DNA amplification from buccal mucosa samples using phi29 DNA polymerase. Total genomic DNA was isolated from buccal mucosa samples obtained from healthy subjects and was amplified using phi29 DNA polymerase. To determine the suitability of the extracted DNA for genotyping, polymerase chain reaction and restriction fragment length polymorphism analyses were performed for the IL-1 gene polymorphism. Genotyping of the IL-1 polymorphism was successful using the amplified DNA from a buccal mucosa, but genotyping was unsuccessful using the unamplified control because of low DNA purity. The method of extracting DNA from a buccal mucosa is painless, simple, minimally invasive, and rapid. Genomic DNA from a buccal mucosa can be amplified by phi29 DNA polymerase in sufficient quantity and quality to conduct gene polymorphism analyses.

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Purpose: In the field of prosthodontics, many methods for evaluating the masticatory function involve ejection of the food bolus from the mouth. In addition, these methods could not evaluate mastication and swallowing function comprehensively. The present study aimed to quantitatively evaluate masticatory functions during a series of masticatory and swallowing movements by using videoendoscopy.
Methods: Subjects are ten healthy dentulous adults without dysphagia. The test foods used were 2-colored (green and white) molded rice and uirou (rice cake). The test foods were consumed under the restriction on the number of mastication (10, 15, 20, and 30), and under the instruction to “chew normally” or “chew well”. The masticatory function was evaluated by observing the food bolus in the oropharynx with a videoendoscope. The bolus formation index (BFI), in terms of the degree of mixing of the green and white parts, was quantitatively determined using an image measurement software.
Results: The BFI of the rice and uirou increased significantly with increase in the number of mastication times (p < 0.01). A significantly correlation coefficient was observed between the BFI and the number of mastication (0.84 for rice and 0.89 for uirou). The BFI obtained by “chewing well” was significantly higher than that obtained by “chewing normally” (p < 0.01).
Conclusions: The results of this study confirm that the endoscopic measurement of food bolus formation by mastication in terms of the color tones of 2-colored test foods enables quantitative evaluation of the masticatory function during a series of masticatory and swallowing movements.

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Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder with periodic reduction or cessation of airflow during sleep. It is associated with loud snoring, disrupted sleep and observed apneas with prevalence up to 54% in elderly people. Treatment of OSA varies from simple measures such as dental appliances and nasal continuous positive airway pressure (CPAP) to surgical procedures like uvulopalatopharyngoplasty and tracheostomy. Dental appliances are a viable nonsurgical treatment alternative in patients with OSA, of which mandibular advancement appliances are most common. Edentulism which contributes to the worsening of OSA reduces the number of available therapeutic strategies and is considered a contraindication to oral appliance therapy. This clinical report describes the treatment of a 61-year old edentulous OSA patient for whom a modified mandibular advancement appliance was designed. The patient reported an improvement in AHI index and he was satisfied with the modified appliance. This clinical report describes the newer technique of fabricating oral appliance for edentulous OSA patient.

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Purpose: Currently, over 40 different types of oral appliances (OA) are available to dentists to treat sleep disordered breathing. OA can be classified by mode of action or design. One of the major categories is tongue retaining device; the other is a mandibular advancement device (MAD). Each device, however, has its own particular drawbacks, the most common revolving around cost or inherent difficulties in the production process.In this present report, we will introduce a “movable” OA which does not disturb the physiologic function. This approach utilizes novel connectors that are both low in cost and involve a straightforward production procedure.
Methods: Our device is categorized as a MAD. The design of the appliance followed that of the cap clasp, and the undercut was set at 0.25 mm. The polyester sheet was pressed to casts via a pressure molding machine, and cut along the design line mentioned above. In our device, we converted a Co–Cr wire as a connector for the OA. From this we developed and applied 2 new connectors for the clinical setting that were low in cost and allowed for mandible movement. These are lingual-side and labial-side types. In this present study the rate of success was 75.5%; with a good response classified as an AHI with less than 5 events/h, or a 50% decrease in their pre-treatment AHI. The efficacy of our OA was equal to previous studies.
Conclusion: In this present report, we could propose inexpensive novel connectors which do not disturb the physiologic function.

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