Journal of Prosthodontic Research
Online ISSN : 1883-9207
Print ISSN : 1883-1958
最新号
選択された号の論文の22件中1~22を表示しています
Review Articles
  • Sara Amghar-Maach, Alba Sánchez-Torres, Octavi Camps-Font, Cosme Gay-E ...
    2018 年 62 巻 4 号 p. 391-396
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: To answer the PICO question: "Among patients to whom an implant is placed, does the piezoelectric surgery (PS) compared to the conventional drilling (CS) achieve higher implant stability, increase surgical time or improve implant survival rate?"

    Study selection: Two independent authors screened the literature through MEDLINE, Cochrane Library and Scopus. Randomized or non-randomized controlled trials, prospective and retrospective cohort studies comparing implant stability and/or clinical outcomes with PS versus CS used for implant site preparation published in the last 10 years were included in the search.

    Results: Five of the 177 articles initially found were included in the meta-analysis. No statistically significant differences were found between PS and CS for implant stability quotient (ISQ) at baseline (SMD: 0.31; 95 %CI: -0.59 to 1.20; p = 0.5). However, ISQ values were significantly higher at 2 months (SMD: 0.52; 95 %CI: 0.03–1.00; p = 0.04) and at 3 months (SMD: 0.74; 95 %CI: 0.17–1.32; p = 0.01) for CS. PS needed significantly more time than CS (SMD: 1.74; 95 %CI: 0.42–3.06; p = 0.01) in order to be performed. No differences for implant survival rates were found when comparing both techniques (RR: 0.52; 95 %CI: 0.09–2.88; p = 0.45).

    Conclusions: PS has not demonstrated superiority to conventional drilling for implant stability during the healing period. PS needs significantly longer surgery time than CS. Differences for implant survival rate were not found between the two techniques.

  • Mireia Haro Adánez, Hironobu Nishihara, Wael Att
    2018 年 62 巻 4 号 p. 397-406
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: This systematic review evaluates the clinical outcome of zirconia implant-associated survival and success rates, marginal bone loss, and implant–restoration complex integrity.

    Study selection: Using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines, studies including ≥10 patients restored with zirconia implants supporting single crowns (SCs) or fixed dental prostheses (FDPs) prior to January 2017 were identified. Primary outcomes were survival rates and marginal bone loss around one and two-piece zirconia implants and the associated implant–restoration complex integrity.

    Results: 1349 studies were selected; after duplicate removal and title screening, 36 remained for full-text screening. 17 studies met the inclusion criteria: 2 randomized controlled clinical studies, 11 prospective clinical studies and 4 retrospective studies. In total, 1704 implants from 1002 patients were evaluated, including 1521 one-piece and 183 two-piece zirconia implants with follow-up between 1 and 7 years. The mean survival rate was 95 % (95 % CI 91–97 %). The overall mean marginal bone loss was 0.98 mm (95 % CI 0.79–1.18); the mean marginal bone loss after 1 year was 0.89 mm (95 % CI 0.60–1.18). No metaanalysis regarding prosthetic outcomes was possible.

    Conclusions: Survival and marginal bone loss values after one year for one-piece zirconia implants are acceptable, but long-term studies are required to support their clinical use. No particular restoration material can be recommended; this decision is apparently based on clinicians' preferences. Results from two-piece implants do not provide sufficient data to support their clinical use and no abutment or cementing materials for two-piece zirconia implants can be recommended.

  • Alexander Mercouriadis-Howald, Noemie Rollier, Sayaka Tada, Gerald McK ...
    2018 年 62 巻 4 号 p. 407-415
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: To analyze the available evidence in the English, German and Japanese literature on the survival and complications of natural teeth with cast copings used to retain overdentures (ROD).

    Study selection: A systematic search strategy was conducted using MeSH terms and pre-defined criteria. Two groups of researchers searched Pubmed, CENTRAL, Embase (English, German), Ichushi-web (Japanese) as well as hand searching. Data were extracted independently by the two groups. The estimated frequency of abutment tooth loss was calculated from data on the number of lost teeth and exposure time. A meta-analysis was conducted to estimate the annual frequency of abutment tooth loss across all included studies.

    Results: A total of 4791 eligible studies from PubMed, Embase, and CENTRAL. An additional 316 articles were identified from the Ichushi-Web plus another 131 articles from additional sources. From those manuscripts,19 reported relevant outcome data that was then extracted. The pooled data included a total of 1954 abutment teeth with a combined total exposure time of 9098 years. The estimated linear rate of loss was 1.76 %/year (95 %CI 1.13; 2.72). Caries and periodontal infections were identified as the most common reasons for abutment tooth loss.

    Conclusions: Natural tooth retained overdentures often constitute the last resort before edentulism and might aid in this transition, especially in very old patients with reduced adaptive capacities. Given correct design, preparation and aftercare, RODs with cast copings, still are a valid treatment option in partially edentulous patients.

Original Articles
  • Katharina Debye, Taskin Tuna, Shaza Bishti, Stefan Wolfart
    2018 年 62 巻 4 号 p. 416-421
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: In implant dentistry, temporary restorations (TR) might often be required for up to one year. The aim of this in vitro study was to evaluate the long-time performance of four-unit TRs in the posterior region based on different materials and reinforcement methods.

    Methods: One hundred and forty four TRs were manufactured on 16 models simulating an oral situation of two missing posterior teeth. With a computer-aided-design/computer-aided-manufacturing (CAD/CAM) workflow, a TR was fabricated (CAD; Telio CAD), which served as a template for other subgroups. With a vacuum-formed template, unreinforced and reinforced TRs [glass fibres (g; EverStick); polyethylenefibres (p; Ribbond original) and TRs with increased connector area (c; 27.5–35 mm2) ] were manufactured. Two different composite materials were used (C1: Luxatemp,C2: Protemp). Altogether, 16 subgroups with 8 specimens each were tested. After temporary luting (Temp Bond NE) and artificialaging [1600 thermo-cycles (5–55 °C), 240,000 chewing-cycles (50 N) ], all specimens were tested until fracture in a universal testing machine.

    Results: After artificial aging, mean fracture loads (N) were: (C1) 201.2 ± 109.7, (C1c) 1033.0 ± 173.1, (C1p) 90.0 ± 40.0, (C1g) 75.9 ± 25.9, (C2) 108.6 ± 58.6, (C2c) 1363.3 ± 148.6, (C2p) 104.7 ± 54.7, (C2g) 50.0 ± 0.0 and (CAD) 232.5 ±19.1. The one-factor ANOVA analysis showed significant differences for the factors temporary material (p < 0.047), reinforcement (p < 0.0001) and artificial-aging (p < 0.0001).

    Conclusions: The study indicated that both CAD/CAM TRs and TRs with increased connector areas are suitable for long-term use of one year. No enhancement of fracture load was observed for fibre-reinforced TRs except for the fact that fractured TRs were not totally separated.

  • Takayuki Ueda, Keitaro Kubo, Takeshi Saito, Tomokuni Obata, Takeshi Wa ...
    2018 年 62 巻 4 号 p. 422-425
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The objective was to investigate the influence of chemical and mechanical cleaning on the surface morphology of a silicone soft relining material.

    Methods: Three plate-shaped specimens were prepared for each group (Control, Hard and Soft) by laminating a 1.5-mm-thick silicone soft relining material. The Control group specimens were stored in water, and the Hard and Soft group specimens were cleaned with hard and soft bristle denture brushes, respectively. Abrasion testing with a toothbrush and immersion testing with an enzyme-containing peroxide denture cleanser were performed, simulating a period of approximately 4 months. The arithmetic mean roughness (Sa) and maximum height of the cross-section (Sz) were measured before and after abrasion and immersion testing.

    Results: Sa was 4.9 ± 0.9, 22.1 ±4.2 and 44.2 ± 4.0 μm in the Control, Soft and Hard groups, respectively. Sz was 257.5 ± 31.7, 392.0 ± 23.8 and 452.2 ± 41.9 μm in the Control, Soft and Hard groups, respectively. After abrasion testing, Sa and Sz differed significantly between the Soft and Control groups and between the Hard and Control groups. Sa was 2.2 ± 1.2 μm before and after immersion, and Sz was 142.1 ± 81.4 μm before and after immersion. No significant difference was noted in either Sa or Sz in the Control specimens before or after immersion.

    Conclusions: Surfaces cleaned using a soft bristle brush were less likely to roughen than those cleaned with a hard bristle brush under the conditions of this study. Additionally, chemical cleaning using the enzyme + neutral peroxide denture cleanser did not roughen the surface of the silicone soft relining material.

  • Maki Hosoki, Keisuke Nishigawa, Toyoko Tajima, Mayu Ueda, Yoshizo Mats ...
    2018 年 62 巻 4 号 p. 426-431
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: Studies have reported cases of metal allergy caused by titanium-containing materials. We wished to clarify the relationship between titanium allergy and dental implants by describing patients who suffered allergic symptoms after they had received such implants.

    Methods: A total of 270 patients who visited a Dental Metal Allergy Clinic at Tokushima University Hospital from April 2010 to March 2014 were the study cohort. Patch testing with 28 types of metal allergens (including four titanium allergens) was undertaken for patients.

    Results: A total of 217 patients (80.4 %) exhibited allergy-positive reactions to at least one type of metal allergen. Mercury, palladium, chromium and nickel exhibited a higher prevalence of allergy-positive reactions than other metals. Sixteen patients visited our clinic suffering allergic symptoms after receiving dental implants. Eleven of those patients exhibited allergy-positive reactions for any of the metal allergens, and 4 of these patients had allergy-positive reactions against titanium allergens. The total number of allergy-positive reactions for titanium allergens among all 270 patients was 17 (6.3 %). No patient exhibited a positive reaction only for the titanium allergen.

    Conclusions: The prevalence of allergy-positive reactions for titanium allergens was lower than for other metal allergens. We suggest examination of pre-implant patients who have a history of hypersensitivity reactions to metals.

  • Koji Morita, Hiroki Tsuka, Kan Kato, Takahiro Mori, Rumi Nishimura, Mi ...
    2018 年 62 巻 4 号 p. 432-435
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: Maintenance of natural dentition and/or prosthodontic rehabilitation is necessary for good masticatory function. Although other factors such as physical and oral functions are also important for masticatory performance, only a few studies have evaluated their roles. The aim of the current study was to assess factors associated with masticatory performance among elderly individuals, while maintaining and/or reconstructing all occlusal support areas.

    Methods: The present study was designed and implemented as a cross-sectional study, involving a total of 262 participants (mean age: 74.2 ± 5.9 years) who participated in the Kyoto Elders Physical Fitness Measurement Research Project. Individuals with partial or complete edentulousness who did not use dentures were excluded from the study. The predictor variables included physical status (i.e., age, gender, body-mass index, and grip strength), oral conditions (i.e., number of present teeth, temporomandibular joint noise, and denture wearer), and oral functions (i.e., maximum voluntary occlusal force; occlusal contact area; cheek pressure; oral diadochokinesis test /pa/, /ta/, /ka/; and maximum voluntary tongue pressure). The variable outcome was masticatory performance. These variables among the participants using univariate and multivariate analyses were compared.

    Results: Grip strength, number of present teeth, maximum voluntary occlusal force, occlusal contact area, oral diadochokinesis /ka/ /ta/, and maximum voluntary tongue pressure were significant factors for masticatory performance. Stepwise regression analysis showed that grip strength, maximum voluntary occlusal force, and diadochokinesis /ta/ significantly affected masticatory performance.

    Conclusions: Masticatory performance was closely associated with grip strength, maximum voluntary occlusal force, and diadochokinesis /ta/ among healthy elderly participants.

  • Ebrahim Maghami, Ehsan Homaei, Khalil Farhangdoost, Edmond Ho Nang Pow ...
    2018 年 62 巻 4 号 p. 436-442
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The aim of this study was to investigate and quantify the effect of preparation design parameters on a premolar restored with two different CAD/CAM ceramic crowns by three-dimensional finite element analysis (FEA).

    Methods: A restored human first premolar was digitized by a micro-CT scanner and a 3D model was created by a medical image processing software (Mimics). Following segmentation, dentine and ceramic were extracted by a surface meshing software (3-matic). Models with different preparation designs with three convergence angles (6°, 12° and 20°) and two preparation heights (3.1 mm and 4.1 mm) were produced. Mesh generation for models was performed in IA-FEMesh software with a lithium disilicate glass ceramic (LD, E = 95.9 GPa) and a polymer-infiltrated ceramic (PIC, E = 30.1 GPa) as the restorative materials. A 5-mm diameter stainless steel hemisphere was employed as an indenter. Twelve models were analyzed numerically in Abaqus™.

    Results: The results indicated that preparation height was found to be a major factor affecting stress distribution in different components. In all models, the maximum principal stress of the ceramic crowns was found in contact area against the indenter. This stress was lesser in the longer abutment than the shorter one and it was greater for LD ceramic. Convergence angle had limited effect on stress distribution of ceramic crown in all models.

    Conclusions: The preparation height appeared to play a more important role in the stress distribution of ceramic crown than the convergence angle.

  • Takamasa Komiyama, Takashi Ohi, Yoshitada Miyoshi, Takahisa Murakami, ...
    2018 年 62 巻 4 号 p. 443-448
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The purpose of this study was to examine whether the status of dentition is associated with incident functional disability in elderly people.

    Methods: This prospective cohort study targeted community-dwelling Japanese adults of age ≥70 years (n = 838). Participants were classified into the following four groups in accordance with Miyachi's Triangular Classification, which represents the status of dentition on the basis of numbers of remaining teeth and occlusal supports: Zone A, ≥10 occlusal supports; Zone B, 5–9 occlusal supports; Zone D, ≤4 occlusal supports and ≥11 remaining teeth and Zone C, ≤10 remaining teeth. Incident functional disability was defined by the first certification of long-term care insurance in Japan. Data regarding age, sex, body mass index, medical history, smoking, alcohol consumption, education, depressive symptoms, cognitive impairment, social support, history of fall, and subjective masticatory ability were collected.

    Results: During follow-up for 5185 person-years, 305 participants experienced functional disability. Considering the follow-up data of ≥3 years from baseline, participants in Zones C (hazard ratio [HR],1.98; 95 % confidence interval [CI], 1.26–3.11) and D (HR, 2.50; 95 %CI, 1.54–4.05) were found to be more likely to develop functional disability than those in Zone A (p for trend = 0.002).

    Conclusions: Status of dentition was associated with incident functional disability in an elderly Japanese population. The findings of this study suggest that maintenance of remaining teeth and retention of occlusal supports contribute to the prevention of functional disability.

  • Taichi Iwashita, Atsushi Mine, Mariko Matsumoto, Hayaki Nakatani, Mami ...
    2018 年 62 巻 4 号 p. 449-455
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The purpose of this study was to evaluate drying methods for post space dentin bonding in a direct resin composite core build-up method.

    Methods: Experiment 1: Four root canal plastic models, having diameters of 1.0 or 1.8 mm and parallel or tapered shapes, were prepared. After drying each post space using three drying methods (air drying, paper-point drying, or ethanol drying, which involves filling the space with 99.5 vol% ethanol followed by air drying), the residual liquid in the models was weighed. Experiment 2: Thirty endodontically treated single-root teeth were dried using the above-described drying methods and filled with dual-cure resin composite. The bonded specimens were sectioned into square beams of approximately 1 mm2 for microtensile bond strength (μTBS) testing. Nine teeth were observed through transmission electron microscopy (TEM) and micro computed tomography (μCT). The weight of residual liquid and μTBS were analyzed using Scheffé multiple comparison.

    Results: Experiment 1: The results of air drying were significantly different from those of paper-point drying (p < 0.001) and ethanol drying (p < 0.001), and no significant difference was observed between paper-point drying and ethanol drying. Experiment 2: The mTBS significantly decreased in the order of ethanol drying, paper-point drying, and air drying (air drying/ethanol drying: p < 0.001, air drying/paper- point drying: p = 0.048, ethanol drying/paper-point drying: p = 0.032). TEM and μCT observation revealed a sufficient dentin/adhesive interface in the ethanol drying group.

    Conclusions: Ethanol drying was found to be more effective for post space dentin bonding, as compared with air drying and paper-point drying.

  • Miguel Simancas-Pallares, Mike T. John, Swati Prodduturu, William A. R ...
    2018 年 62 巻 4 号 p. 456-461
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: To develop a Spanish version of the Orofacial Esthetic Scale (OES-Sp) and to determine its psychometric properties in dental patients.

    Methods: We performed a validation study for OES development and validation into Spanish. In the development phase, eight individuals participated in the translation process (cross-cultural adaptation) following the PROMIS methodology. In the validation phase, 331 dental patients (age mean ± sd: 42.9 ± 12.3 years, 59 % female) from the HealthPartners dental clinics in Minnesota, USA responded to a survey of Spanish speaking patients (n = 540, response rate: 61 %). We first explored dimensionality by means of exploratory factor analysis and scree plot, and then we computed reliability measures with the Cronbach's alpha statistic. Finally, we assessed convergent validity by computing Pearson/Spearman rank correlations between OES-Sp and Oral Health Impact Profile (OHIP)-based orofacial appearance measures. All statistical procedures were performed using Stata v.13 for Windows (StataCorp).

    Results: Exploratory factor analysis provided evidence that a single factor represents the Spanish OES version. Score reliability was high with Cronbach's alpha statistic of 0.95 (lower limit of the 95 % CI: 0.94). Score validity was sufficient indicated by Pearson and Spearman rank correlations between -0.53 and -0.69 (all 95 % confidence intervals: less than ± 0.10).

    Conclusions: OES is a valuable instrument to measure the orofacial appearance construct for Spanishspeaking populations. OES was concluded to be unidimensional with excellent score reliability and sufficient convergent score validity when compared with other Orofacial Appearance measures. Our results suggest that OES could be used in Spanish-speaking patients, an important and growing population around the globe.

  • Farahnaz Nejatidanesh, Ghazal Savabi, Mehrak Amjadi, Mahsa Abbasi, Omi ...
    2018 年 62 巻 4 号 p. 462-467
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The aim of this clinical study was to compare the survival, modified California Dental Association (CDA) criteria, and periodontal parameters of laminate veneers made with Empress CAD and emax CAD over 60 months.

    Methods: One hundred and ninety seven ceramic laminate veneers were placed in 71 patients in a private practice. The restorations were made using CEREC AC Bluecam with Empress CAD and emax CAD blocks. Modified CDA guidelines were used to evaluate clinical performance of the restorations. Gingival and plaque indices, probing pocket depth, and bleeding on probing were also recorded. Patient's satisfaction was assessed using visual analogue scale. Kaplan–Meier and Log rank test were used to analyze survival probability and success rate of the restorations. CDA rating of Empress CAD and emax CAD was compared with Log rank test (α = 0.05).

    Results: The survival rates of ceramic Empress CAD and emax CAD laminate veneers were 97.8 % and 100 % respectively (p = 0.13). The success rate of these veneers was 92.4 % for Empress CAD and 100 % for emax CAD (p < 0.05). Two Empress CAD laminate veneer failed because of fracture. Other restorations had very good or good CDA scores after 5 years. The periodontal parameters were not significantly different between first and fifth years except plaque index. The mean score of patients' satisfaction was 95.5 ± 8.4.

    Conclusions: Chair-side computer-aided design/computer-aided manufacturing ceramic laminate veneers were clinically successful restorations with mean survival rate of 99.0 % and success rate of 96.4 % after 5 years.

  • Mario Alovisi, Nicola Scotti, Allegra Comba, Elena Manzon, Elena Farin ...
    2018 年 62 巻 4 号 p. 468-472
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: The aim of this in vitro study was to assess conversion degree (DC), micro-hardness (MH) and bond strength of two dual-curing resin cements employed under translucent monolithic zirconia irradiated with different time protocols.

    Methods: 84 square shaped samples of 1 mm thickness were prepared from high translucency zirconia blocks and divided into two groups (n = 24) according to the cement employed: (1) Rely-X Ultimate; (2) Panavia SA. Each group was further divided into 3 subgroups (n = 8) according to the irradiation time: (a) no light; (b) 20 s; (c) 120 s. Light curing was performed 60 s after the sample was placed on the diamond support of a FT-IR spectrophotometer with a high power multiLED lamp. Final DC% were calculated after 10 min. After 24 h, Vickers Test on the cement layer was performed. The same protocol was used to lute composite cylinders in order to evaluate microshear bond-strength test. ANOVA and Bonferroni tests were performed to find differences between MH and bond-strength to zirconia, while for DC% the Scheirer–Ray–Hare two-way test was used.

    Results: The two cements reached higher DC% in subgroup (b) and (c). As concern MH, statistics showed an increase in curing time was able to improve MH significantly. Bond-strength was not affected by irradiation time only for Panavia SA.

    Conclusions: The first null hypothesis has to be rejected since DC% and MH of the dual-cements tested were influenced by the curing time. The second null hypothesis is partially rejected since the bond strength was influenced by the curing time only for Rely-X Ultimate.

  • Mariela Machado, Christine Wallace, Bruce Austin, Suhas Deshpande, Agn ...
    2018 年 62 巻 4 号 p. 473-478
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: This study has evaluated the pre and post perceptions of patients with ectodermal dysplasia (ED) who have been referred to Westmead Centre for Oral Health for treatment with dental implants.

    Methods: Six patients with ED and hypodontia were treated with new maxillary complete dental prostheses or fixed implant prostheses, and a mandibular fixed dental prosthesis with implants. Patient perceptions were recorded with a 10 cm visual analogue scale (VAS). All patients were asked to draw a line on the VAS which best described their feelings regarding aesthetics, chewing, diet and speech.

    Results: Improvement in aesthetics was reported for all patients with change scores ranging from +9 to +4 points. Similarly, all patients reported an improvement in chewing ability with +6 point changes in 2 patients, and +8, +3, +7 and +1 in the other 4 patients. Five out of 6 patients reported less dietary restriction with 3 patients each indicating a change of +6 points, +4 points, +3 points, and 2 patients reporting +1 point change. Speech improved by +1 point for 3 patients, whilst 1 patient improved by +6 points, a further 2 patients scored no change.

    Conclusions: Patients with ED treated with dental implants reported encouraging outcomes post treatment after prostheses were fitted. Follow-up from 1.6 to 6.8 years has confirmed these improvements.

  • Anna Paula da Rosa Possebon, Raissa Micaella Marcello-Machado, Amália ...
    2018 年 62 巻 4 号 p. 479-484
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: Evaluate how clinical factors related to conventional complete denture (CCD) wearers, can influence masticatory function (MF) of totally edentulous patients before and after one-year transitioning to implant-retained mandibular overdentures (IMO).

    Methods: Forty patients using CCD were rehabilitated with IMO and their MF was evaluated by: (i) ST_X50: theoretical aperture through which 50 % of the weight of the particles would pass; (ii) STB: distribution homogeneity of the crushed particles. The clinical parameters analyzed were: atrophy, retention, stability, facial type, anteroposterior skeletal discrepancy, and type of loading. The statistical association was tested through crude and adjusted logistic regression.

    Results: IMO promoted improvements in the MF, irrespective of the clinical parameters. CCD wearers with poor retention had 86 % less chance of achieving a good ST_X50. STB was associated with stability, facial type, and anteroposterior discrepancy. Subjects with poor mandibular CCD stability had a 76 % lower chance of achieving a good test food homogenization, whereas brachyfacial individuals were 1.3 times more likely to have a good STB. Class II patients had an 89 % lower chance of having a good homogenization of the particles as CCD users and after transition to IMO.

    Conclusions: CCD users with poor retention achieved an inferior ST_X50. The STB performance can be compromised by poor stability or Class II characteristics, while brachyfacial individuals achieve better homogenezation of the food bolus. Although the transition to IMO improved the masticatory function, the anteroposterior discrepancy still maintained an association with STB, as Class II individuals still presented difficulties homogenizing food.

  • Yuko Watarai, Fumi Mizuhashi, Toshihide Sato, Kaoru Koide
    2018 年 62 巻 4 号 p. 485-489
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: A new method inducing the physiologic rest position of the mandible using the lip contact position with the closed mouth have compared with those obtained using conventional methods of placing the mandible in the physiologic rest position.

    Methods: The lip contact position with the closed mouth as a method was investigated whether the technique was useful for determining the occlusal vertical dimension. The relationship between the space between the maxillary and mandibular front teeth in the lip contact position with the closed mouth and the areas of the prolabia was also investigated.

    Results: Median space between the maxillary and mandibular front teeth in the lip contact position with the closed mouth was 1.53 mm, a value intermediate between the value of 2.16 mm in the resting mandibular position obtained by the conventional technique and that of 1.33 mm in the swallowing position. The coefficient of variation of the space in the lip contact position with the closed mouth was significantly lower than those in the resting mandibular position and in the swallowing position. A significant positive correlation was recognized between the space in the lip contact position with the closed mouth and the area of the prolabium of the upper lip.

    Conclusions: These results clarified that the lip contact position with the closed mouth obtained the excellent reproducibility comparing to the conventional methods. These findings suggested that the area of the prolabium of the upper lip might offer an effective index for individual determination of the correct free-way space.

  • Tokinori Kato, Tamaki Nakano*, Yuya Fujita, Tomoyuki Kobayashi, Hirofu ...
    2018 年 62 巻 4 号 p. 490-496
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: To prospectively evaluate morphological changes in the horizontal and vertical dimensions of peri-implant tissue at 1-year post-prosthesis implantation.

    Methods: Thirty-four patients who had received implants with conical connections in the aesthetic region were included in the follow-up study. Patients had received either traditional delayed implant placement or tissue augmentation with or without immediate implant placement. The horizontal and vertical dimensions of the buccal alveolar bone of the implant and its surrounding soft tissues were then evaluated using cone beam computed tomography.

    Results: Implants placed alongside tissue augmentation, with or without immediate placement, were as successful as those placed into sites with traditional delayed implant placement. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone height (r = 0.585, p < 0.05) and vertical soft tissue height (r = 0.378, p < 0.05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (r = 0.627, p < 0.05).

    Conclusions: Regardless of the bone and soft tissue augmentation approach, implants with conical connections may effectively preserve peri-implant tissues. However, the thickness of the peri-implant soft tissue is essential, because a change in soft tissue margin level tends to be affected by the thickness of the peri-implant soft tissue rather than the bone width.

  • Shuhua Wang, Toru Ogawa, Sheng Zheng, Makiko Miyashita, Taichi Tenkumo ...
    2018 年 62 巻 4 号 p. 497-502
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: Low-magnitude, high-frequency (LMHF) loading plays an important role in bone healing. The present study aimed to evaluate the effect of LMHF loading applied directly to titanium dental implants on peri-implant bone healing and implant osseointegration.

    Methods: The mandibular premolars and molars were extracted from six male Beagle dogs. Three months post-extraction, each of the six dogs had three titanium implants (Aadva Standard Implant Narrow, Φ3.3 × 8 mm) inserted into the mandibular premolar and molar area (three implants per side). In each animal, one side was randomly selected to undergo daily LMHF loading (treatment group), while the other side had no further intervention (control). The loading was applied directly to the implant abutment using an individual jig and a custom-made loading device (8 mm, 100 Hz). The implant stability quotient (ISQ) was tested every week. Three dogs were euthanized after 2 weeks, and three were euthanized after 8 weeks. Tissue samples were fixed and stained for micro-computed tomography (micro-CT) and histomorphometric analyses. Data were analyzed statistically, with significance set at p < 0.05.

    Results: The treatment group had significantly increased peri-implant bone volume relative to tissue volume in region of interest 2 (100–500 mm) compared with the control group after 2 weeks of loading (p < 0.05); however, there was no significant difference between groups after 8 weeks. The ISQ value and the micro-CT results did not differ between groups during the study period.

    Conclusions: LMHF loading positively influenced peri-implant bone healing in the early healing period.

  • Panagiotis Lagouvardo, Nikolina Spyropoulou, Gregory Polyzois
    2018 年 62 巻 4 号 p. 503-508
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: This study investigates the perceptibility and acceptability thresholds (PT, AT) of observers for L*, a* and b* facial skin differences, very important for the fabrication of a maxillofacial prosthesis.

    Methods: One image (10 × 13.3 cm/300 dpi), simulating standard facial skin color, and 27 smaller images (4.9 × 6.0 cm/300 dpi), simulating shades with different RGB values from the standard were made, using Adobe-Photoshop CS3. The RGB values, were based on 9 stepped increases in L*, a* and b*. Images were shown in the middle of a computer screen with the standard image in the background. 90 persons with normal color vision and optical acuity were selected and instructed to evaluate 81 (27 × 3) randomly shown images for a perceptible or an acceptable (48 h later) mismatch, between central and background image. Using best fitting regression curves 50 % PT and 50 % AT for all parameters were estimated along with their 95 %CI.

    Results: Observers' reliability found high (0.807–0.945) while the cubic and exponential were the best fitted curves to the data. Overall 50 % ATs were smaller than 50 % PTs (p < 0.01) and overall ΔL* parameter showed the lowest thresholds (0.119PT/0.864AT), significantly smaller (p < 0.05) than Δa* (0.993PT/ 2.037AT), Δb* (1.147PT/2.517AT), and ΔEab* (1.497PT/1.808AT). No differences were found between sex or age groups in 50 % ATs for Δa* and Δb* parameters, but 50 % PT for Δa* was smaller in females and in older people with the opposite for Δb*.

    Conclusions: Changes in L* were more perceptible and less acceptable than changes in a* and b*. For this reason ΔL* parameter needs attention equally to ΔE*ab when fabricating a facial prosthesis.

Technical Procedures
  • Manabu Kanazawa, Maiko Iwaki, Toshio Arakida, Shunsuke Minakuchi
    2018 年 62 巻 4 号 p. 509-513
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: This article describes the protocol of a digital impression technique to make an impression and recording of the jaw relationship of edentulous patients for the fabrication of CAD/CAM custom tray using computer-aided design and manufacturing (CAD/CAM) technology.

    Methods: Scan the maxillary and mandibular edentulous jaws using an intraoral scanner. Scan the silicone jig with the maxillary and mandibular jaws while keeping the jig between the jaws. Import the standard tessellation language data of the maxillary and mandibular jaws and jig to make a jaw relation record and fabricate custom trays (CAD/CAM trays) using a rapid prototyping system. Make a definitive impression of the maxillary and mandibular jaws using the CAD/CAM trays.

    Conclusions: Digitalization of the complete denture fabrication process can simplify the complicated treatment and laboratory process of conventional methods In addition, the proposed method enables quality control regardless of the operator's experience and technique.

  • Alessandro Pozzi, Lorenzo Arcuri, Peter K. Moy
    2018 年 62 巻 4 号 p. 514-517
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Purpose: To introduce a proof of concept technique and new integrated workflow to optimize the functional and esthetic outcome of the implant-supported restorations by means of a 3-dimensional (3D) facially-driven, digital assisted treatment plan.

    Methods: The Smiling Scan technique permits the creation of a virtual dental patient (VDP) showing a broad smile under static conditions. The patient is exposed to a cone beam computed tomography scan (CBCT), displaying a broad smile for the duration of the examination. Intraoral optical surface scanning (IOS) of the dental and soft tissue anatomy or extraoral optical surface scanning (EOS) of the study casts are achieved. The superimposition of the digital imaging and communications in medicine (DICOM) files with standard tessellation language (STL) files is performed using the virtual planning software program permitting the creation of a VDP.

    Conclusions: The smiling scan is an effective, easy to use, and low-cost technique to develop a more comprehensive and simplified facially driven computer-assisted treatment plan, allowing a prosthetically driven implant placement and the delivery of an immediate computer aided design (CAD) computer aided manufacturing (CAM) temporary fixed dental prostheses (CAD/CAM technology).

  • Hanako Suenaga, Toru Tamahara, Mina Dodo, Toshimitsu Murakami, Satoshi ...
    2018 年 62 巻 4 号 p. 518-521
    発行日: 2018年
    公開日: 2018/11/26
    ジャーナル 認証あり

    Patients: Seventy-one and 73 years-old males visited a perioperative oral care support center to receive perioperative oral management during tongue cancer (T1N0M0) treatment. To improve their quality of life (QOL) during brachytherapy while preventing radiation-related complications including osteoradionecrosis due to 198Au grain brachytherapy, spacers for their maxilla and mandible were designed with consideration of wearing condition at an isolation ward. The spacer was created with unilateral design and with consideration of the tongue mobility during day and night. Then, the spacer was thickened on the plaster model, demonstrating the cancer lesion in the tongue in order to secure the distances from the mandibular body, maxilla and sublingual gland to the radiation sources embedded in the tongue.

    Discussion: Tongue impression made the spacers as small as possible by thickening just around the cancer lesions so that the patients could wear them comfortably, while keeping adequate distance between the radiation sources and peripheral normal tissues. Breakable hard materials were avoided so that the patients were able to utilize the spacers safely without accidentally swallowing a broken fragment. Additionally, considering the upward movement of the tongue in a sleeping posture, the upper spacers were also prepared to protect the maxillae. Computer simulation revealed that the design of our spacers had enough effect on a reduction in radiation to prevent osteoradionecrosis in the maxilla as well as mandibular body.

    Conclusions: This report demonstrated the importance of the spacers created with consideration of patients' wearing condition to improve their QOL during brachytherapy.

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