Prosthodontic Research & Practice最新文献

{"title":"Influence of a Vent Hole on the Retentive Force of a Cement-retained Superstructure before/after Thermocycling","authors":"Jianrong Chen, K. Nagao, Y. Tomotake, K. Oka, M. Hada, T. Ichikawa","doi":"10.2186/PRP.5.157","DOIUrl":"https://doi.org/10.2186/PRP.5.157","url":null,"abstract":"Purpose: The purpose of this study was to evaluate the influence of a vent hole on the retentive force of a cement-retained superstructure to an abutment.Methods: The retentive force of superstructures with/without a vent hole, retained using one of two luting cements, was measured using a universal testing machine both before and after thermocyclingResults: The retentive force of the cement-retained superstructure with the vent hole was greater than that of the cement-retained superstructure without the vent hole. While the retentive force decreased significantly after thermocycling, the size of the vent hole had little influence on the retentive force.Conclusion: It was concluded that placement of a vent hole in the superstructure is useful, with little adverse effect on the retentive force of the restoration.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114173371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoelastic Evaluation of Load Transfer to an Implant Connected to a Natural Tooth under Varying Types of Periodontal Support","authors":"S. Ozawa, K. Ochiai, A. Caputo, R. Nishimura, Yoshinobu Tanaka","doi":"10.2186/PRP.5.129","DOIUrl":"https://doi.org/10.2186/PRP.5.129","url":null,"abstract":"Purpose: The purpose of this study was to compare the stress transfer from a fixed restoration, supported by an implant restored with either a segmented or non-segmented implant abutment, connected to a simulated tooth with decreased foundational support by photoelastic evaluation.Methods: A photoelastic model of a human left mandible, edentulous posterior to the first premolar, was fabricated, with a 3.75×13 mm screw-type implant embedded within the edentulous area. The edentulous areas were restored with a three-unit fixed prosthetic restoration with the distal implant abutment connected to the simulated tooth abutment. The implant abutments consisted of either a segmented conical abutment or a non-segmented UCLA abutment. A hemiseptal periodontal defect was created by the removal of buccal and disto-buccal tissues to simulate decreased support caused by a 4 mm infrabony defect. Vertical occlusal loads were applied at fixed locations on the restorations for the simulated periodontal condition. The stresses which developed in the mandible were monitored photoelastically and recorded photographically.Results: Decrease of the foundational support of the tooth resulted in higher stresses transferred to the mesial and apical aspects of the implant as compared with those in the non-defect control condition. Similar results were obtained for both segmented and nonsegmented abutment restorations.Conclusion: Within the limitations of this study, application of load to the simulated abutment teeth with decreased periodontal support resulted in higher stresses around the supporting implant structure for both abutment designs. The distribution and intensity of the stresses were similar for segmented and nonsegmented abutments.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116673620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Midline Position and Incisal Inclination on Esthetic Evaluation of Complete Denture Wearers","authors":"T. Seki, Tetsuya Suzuki, I. Hayakawa","doi":"10.2186/PRP.5.150","DOIUrl":"https://doi.org/10.2186/PRP.5.150","url":null,"abstract":"Purpose: This study was conducted to determine the esthetically acceptable range of deviation of the midline position and incisal inclination of complete dentures, based on the results of esthetic evaluation conducted under various midline positions and degrees of incisal inclination in complete denture wearers. In addition, the influence of anatomic landmarks of the face in the evaluation of the midline position was also examined.Methods: Frontal pictures of each of 10 complete maxillomandibular denture wearers were taken, with the lips opened in the intercuspal position. Each image was processed to yield 21 images with varying midline positions (±2.5 mm at 0.5-mm intervals) and varying degrees of incisal inclination (±2.5 degrees at 0.5-degree intervals) for evaluation. These images were presented to the examiners (20 dentists and 20 dental students), who gave a score of 0 to the images that appeared esthetically unacceptable, 1 to those that appeared neutral, and 2 to those that appeared esthetically acceptable. The scores of each image were totalled to yield the natural appearance score. We checked for significant differences in the natural appearance score between control images and each of the images evaluated in this study.Results: No significant difference in the natural appearance score was noted when the midline deviation was within ±1 mm (in the evaluation by dentists) or ± 1.5 mm (in the evaluation by students) (P>0.05). In addition, no significant difference in the score was noted when the incisal inclination was between −2 and +1.5 degrees (in the evaluation by dentists) or between −2.5 and +2 degrees (in the evaluation by students) (P>0.05).Conclusion: The results suggest that in complete denture wearers, midline deviation within ±1 mm and incisal inclination within ±1.5 degrees are esthetically acceptable.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125443403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of the Perioral Muscle Electromyographic Activities during Jaw Functions in Healthy Young Adults","authors":"Yoshimi Inoko, K. Yoshimura, O. Morita","doi":"10.2186/PRP.5.166","DOIUrl":"https://doi.org/10.2186/PRP.5.166","url":null,"abstract":"Purpose: The aim of the present study was to record the electromyographic (EMG) activity of the mentalis muscle (Ment) during various jaw functions in healthy young subjects.Methods: Twelve healthy males were enrolled for the study. A portable EMG recording device was used to record the EMG activity from the Ment, anterior belly of the digastric muscle (Dig), and the masseter (Mm) muscles. The EMG activities of these muscles were recorded during maximal voluntary clenching (MVC), maximal voluntary jaw opening (MVO), and the masticatory process. The EMG activity of Ment was compared with the EMG activities of Dig and Mm during various jaw functions.Results: (1) The EMG activities of Ment and Dig were significantly greater during MVO than during MVC (P<0.05). A strong correlation was found between the activities of Ment and Mm during MVO (r=0.739, P<0.01), and between those of Ment and Dig during MVC (r=0.664, P<0.05). (2) It was observed that during mastication of peanuts, Ment showed synchronous activity with that of Dig and reciprocal activity with that of Mm.Conclusion: These results indicate that Ment acts in coordination with the actions of Dig and Mm during various jaw functions.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127036930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thin Films formed by Radiofrequency Sputtering of β-tricalcium Phosphate","authors":"K. Kimoto, A. Watazu, Kinya Tanaka, T. Sonoda, Sachio Kushida, Noriyuki Hoshi, Tomoji Sawada, M. Toyoda","doi":"10.2186/PRP.5.137","DOIUrl":"https://doi.org/10.2186/PRP.5.137","url":null,"abstract":"Purpose: The purpose of this study was to evaluate the feasibility of formation of thin film coatings of bioactive ceramics, such as β-tricalcium phosphate (β-TCP), by radio frequency (RF) sputtering. In this paper, we report the results of our preliminary attempts, as a trial of this concept, to use radio frequency sputtering for obtaining thin film coatings of a ceramic substance on a quartz glass substrate.Methods: We attempted to obtain a thin film coating of β-TCP on a quartz glass surface using an RF sputtering deposition system (L-332S-5FHS, ANELVA, Japan). We examined the thickness of the films deposited on the quartz glass substrate with a confocal laser scanning microscope and characterized the films by electron probe microanalysis (EPMA), scanning electron microscopy (SEM), X ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis.Results: The films were found to be about 0.51 μm in thickness. Although our attempt was directed at obtaining a β-TCP coating on the quartz glass surface, the resultant film consisted of Ca and P in the ratio of 3:1, and was almost amorphous. However, the Ca and P were uniformly distributed on the surface of the films, confirming the feasibility of using an RF sputtering system to obtain a homogeneous film coating.Conclusion: Our results suggest that RF sputtering may be a feasible technique for the preparation of ceramic coatings.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124855430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Teeth Clenching on the Bodily Equilibrium against Striking Weight Impact","authors":"Shinsuke Tanaka, T. Hirai, H. Koshino, Y. Yokoyama, T. Ishijima","doi":"10.2186/PRP.5.143","DOIUrl":"https://doi.org/10.2186/PRP.5.143","url":null,"abstract":"Purpose: The purpose of this study was to elucidate the influence of teeth clenching on the head posture and body sway during an impact lord to the greater trochanter of the femur.Methods: The sternocleidomastoid muscle activities, head posture, and the total locus length of head movement and body sway during and in the absence of a striking weight impact under the resting position of the mandible and during 50% and 100% voluntary maximal clenching were analyzed.Results: 1) The activity of the sternocleidomastoid muscles increased with the teeth clenching force, and the increase was greater during a striking weight impact than that in the absence of a striking weight impact. 2) The decrease in the lateral bending and rotation angles of the neck observed during a striking weight impact was greater under the voluntary teeth clenching conditions as compared with that under the resting position of the mandible. 3) The total locus length of the head movement and body sway were shorter under the voluntary teeth clenching conditions as compared with that under the resting position of the mandible. 4) In contrast to the observations under the resting position of the mandible during a striking weight impact, the ratio of the total locus length of the head movement to that of the body sway under the voluntary teeth clenching during a striking weight impact decreased to the level noted under the resting position of the mandible in the absence of a striking weight impact.Conclusion: The results of this study suggest that teeth clenching stabilizes the head in cooperation with the activities of the sternocleidomastoid muscles, and prevents excessive head movement and body sway during a striking weight impact.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127312445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Immersion in Warm Water on Bonding Strength between Autopolymerizing Resin and Denture Base Resin","authors":"T. Ueda, Miki Ryuzaki, Harunaka Ishii, T. Sugiyama, K. Sakurai","doi":"10.2186/PRP.5.161","DOIUrl":"https://doi.org/10.2186/PRP.5.161","url":null,"abstract":"Purpose: The purpose of this study was to investigate the influence of immersion in warm water and the timing of the immersion on bonding strength between a built-up self-curing resin and a heat-cured denture base resin.Methods: In this study, self-curing resins (Unifast II or Unifast Trad) were built up on denture base resins after surface treatment of the latter with or without primer. The specimens were cured under three conditions (immersion in warm water for 10 s after build-up (E), immersion in warm water for 210 s after build-up (L), and without immersion in warm water (N)), and shear bond strength and failure patterns were measured.Results: For Unifast II without primer, there were significant differences in shear bonding strength between conditions E and L, or conditions E and N. A cohesion failure rate of 70% was noted under condition E. Bonding strength of Unifast II with primer also differed significantly between conditions E and L. There were no correlations between the failure patterns and the curing conditions. For the case of Unifast Trad without primer, no significant difference was in the bonding strength were observed under the different conditions, whereas for that with primer, significant differences in bonding strength were observed between conditions L and N. Since the failure pattern in all cases was represented by cohesion failure, there was no statistically significant relationship between the curing conditions and the failure pattern.Conclusion: Immersion in warm water at the beginning of the polymerization response enhances the bonding strength of Unifast II to denture base resin without primer. On the other hand, for the cases of both Unifast II with primer and that of Unifast Trad with and without primer, there was no correlation between immersion in warm water during polymerization of the resin and bonding strength.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128327057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occlusal Factors associated with Temporomandibular Disorder based on a Prospective Cohort Study of Young Adults","authors":"Masatoshi Kawan, M. Fujisawa","doi":"10.2186/PRP.5.72","DOIUrl":"https://doi.org/10.2186/PRP.5.72","url":null,"abstract":"In this prospective cohort study, mandibular movement analysis was conducted together with clinical examinations to determine the intrinsic occlusal factors that might contribute to the development of TMD. Since mandibular movement analysis has never been conducted previously in this type of cohort study, our results highlight the important implications of occlusal factors potentially associated with TMD. Abstract Purpose: To determine the relationship between temporomandibular disorders (TMD) and the occlusal contact pattern, we conducted occlusal analysis in a prospective cohort study. Methods: One hundred forty-six volunteers consisting of 98 males and 48 females with a mean age of 20.0±1.9 years selected from the dental students of Iwate Medical University were enrolled for the study. All the subjects were asked to fill out a self-adminis-tered questionnaire to screen their general and oral health conditions, and then clinical examination, including evaluation of the occlusal contact pattern, was conducted during the first year. A second clinical examination was repeated 2.5 years later to ascertain the incidence of symptoms of TMD. The natural course of TMD symptoms in the 128 subjects were as follows: group, group, remission group, and continuation group. lateral mandibular types: ④ non-working side molar guided occlusion (NM; n=4), and ⑤ incisal guided occlusion (IG; n=5). Results: In the second examination, 18 out of the 84 subjects (21.4%) who showed no symptoms at the time of enrolment into the study reported TMJ click and/or pain. Of the total, 23, 11, 1, and 1 subjects with symptoms of temporomandibular joint origin were classified as having the CG, WM, NM, and BG pattern of occlusal contact, respectively. With CG as the standard, the relative risk of TMD in subjects shown the WM pattern was 2.79 (95%CI: 1.16 – 6.70). Conclusion: Since the group showing the working side molar guided occlusion pattern showed a high risk of future development of TMJ click and/or pain, lateral excursion guidance may be a contributing factor for the development of TMD.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128502265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Cutoff Values on the 100-mm Visual Analogue Scale to Classify the Satisfaction Levels of Complete Denture Wearers","authors":"Y. Kawai, Hiroyuki Ajiro, Ai Takeo, Takehiko Kondoh, Yousuke Ohno, Ai Yamakawa, A. Gunji, Kihei Kobayashi","doi":"10.2186/PRP.5.91","DOIUrl":"https://doi.org/10.2186/PRP.5.91","url":null,"abstract":"Purpose: The purpose of this study was to determine the optimum cutoff values on a 100-mm visual analogue scale (VAS) for assessing patients'level of satisfaction with their complete dentures, and to extend its use in the clinical setting.Methods: Cross-sectional consecutive sampling was conducted to gather subjective ratings of existing complete dentures using both VAS and a four-point verbal descriptive scale (VDS). Eighty-two edentulous individuals (39 male and 43 female; mean age: 71.6±8.1years) participated in the study. The satisfaction ratings for existing dentures were measured using both the VAS and the four-point VDS at baseline. Agreement between the patient ratings on the VAS and the four-point VDS was analyzed by Spearman rank correlation coefficient, and the cutoff values were estimated by analysis of the receiver operating characteristics (ROC).Results: There was significant agreement between the patient ratings on the VAS and the four-point VDS (overall: r=0.84, P<0.001; maxillary: r=0.75, P<0.001; mandibular: r=0.81, P<0.001). The cutoff points on the VAS were clarified for the overall (dissatisfied: 0–31; slightly dissatisfied: 31+–50; slightly satisfied: 50+–79; satisfied: 79+), maxillary (dissatisfied: 0–47; slightly dissatisfied: 47+–52; slightly satisfied: 52+–80; satisfied: 80+), and mandibular (dissatisfied: 0–36; slightly dissatisfied: 36+–48; slightly satisfied: 48+–83; satisfied: 83+) satisfaction.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126696922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disposable Dust Chamber for Home-visit Prosthodontic Treatments","authors":"K. Tsuga, Mariko Maruyama, R. Hayashi, T. Taji, Y. Akagawa","doi":"10.2186/PRP.5.113","DOIUrl":"https://doi.org/10.2186/PRP.5.113","url":null,"abstract":"Purpose: The aim of this article is to describe the procedure for preparing a disposable dust chamber for use in home-visit prosthodontic treatments, that is economical and can be made from materials that are easy to procure.Methods: After cutting off both ends, the main body of a PET bottle (capacity:1.5 to 2.7 liters) is trimmed to a length of about 15-20 cm. A disposable glove is slipped over each cut end of the PET bottle. The finger and palm portion of the gloves at both ends are then cut off.Results: Users can work on prostheses within this dust chamber, without dispersing the flying particulate waste produced by the grinding into the ambient air. After use, the chamber can be washed with tap water, and be reused after disinfection. This device also effectively reduces the noise produced by the cutting and grinding.Conclusion: A low-cost handy disposable dust chamber that can be made easily is presented.","PeriodicalId":306414,"journal":{"name":"Prosthodontic Research & Practice","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121371073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}