The International Journal of Prosthodontics, 03/2017

Purpose: The aim of this study was to test the null hypothesis that there is no difference in implant failure rates, marginal bone loss, and postoperative infection for implants inserted in bone with different qualities and quantities according to the classification of Lekholm and Zarb. Materials and Methods: An electronic search was undertaken in January 2015 for randomized and nonrandomized human clinical studies. Results: A total of 94 publications were included. When bone sites of different qualities were considered, the results suggested the following comparative implant failure rates: 1 > 2, 1 > 3, 3 > 2, 4 > 1, 4 > 2, and 4 > 3. Sensitivity analyses suggested that when implants inserted in bone qualities 1 and 2 and 1 and 3 were compared, oxidized and sandblasted/acid-etched surfaces showed a decrease in significant difference in failures compared with turned implants. The same is not true for failure of implants inserted in bone quality 4 compared to failure of implants in all other bone qualities. When bone sites of different quantities were considered, the following comparative implant failure rates were observed: A > B, A > C, A < D, B < C, B < D, C < D, E > A, E > B, E > C, E > D. Due to insufficient information, meta-analyses for the outcomes postoperative infection and marginal bone loss were not performed. Conclusion: Sites with poorer bone quality and lack of bone volume may statistically affect implant failure rates. Implant surfaces may play a role in failure of implants in different bone qualities.

Two patients with a reduced vertical dimension of occlusion as a result of teeth wear were prescribed ceramic overlays. Their 2-year follow-up suggested good adaptation to the recovered muscle support without associated symptoms or adverse alterations in the restorations.

Purpose: The purpose of this preliminary in vivo study was to compare force distribution on abutments (tooth or implant) and tissues supporting overdentures with two or four abutments. Materials and Methods: A convenience sample of five subjects with tooth and/or implantsupported overdentures was enrolled. Recordings were completed on each subject using a forcemeasuring system mounted on a metal framework with four anteroposterior spread abutments (A), four abutments with denture bases (B), and on two anterior abutments with denture bases (C). The tissue-support ratio (TSR) was calculated as (A−B)/A or (A−C)/A. Results: TSR values changed 1.5 to 2 times when the number of abutments was reduced from four to two. Conclusion: The amount of tissue strain on the posterior residual ridge increased when the number of abutments was reduced.

Since their introduction, implant-retained overdentures have represented a feasible, economical, and highly successful treatment option for completely edentulous patients. Different attachment systems have been effectively used to retain these implant overdentures, and each system has advantages and disadvantages. Locator attachment (Zest Anchors) is one system that has been widely used by clinicians, particularly, for two-implant-supported situations. Recently, Zest Anchors developed a new locator-style abutment, Locator R-Tx. This clinical report describes the fabrication of a mandibular two-implant overdenture using this newly designed attachment system and reviews the different attachment systems currently in clinical use.

Purpose: The aim of this study was to determine the optimal number and location of miniimplants retaining an overdenture to resist lateral forces. Materials and Methods: A strain gauge was attached to a mini-implant and placed in an edentulous mandible model. The following different implant locations were evaluated: one mini-implant at the midline, two miniimplants in the lateral incisor regions, two mini-implants in the canine regions, and four miniimplants. Results: Lateral forces on mandibular overdentures retained by one mini-implant at the midline or two mini-implants in the lateral incisor regions appeared to be advantageous when compared with placing two mini-implants in the canine regions or four mini-implants. Conclusion: Fewer mini-implants resulted in less lateral stress, while four were associated with an unequal stress distribution.

Purpose: The aim of this study was to examine whether psychopathologic profile is related to the location of pain in temporomandibular disorder (TMD) patients with myofascial and/or temporomandibular joint pain. Materials and Methods: A total of 75 painful TMD patients (39 women and 36 men) participated in the study. Participants were divided into three groups (myogenous, arthrogenous, and mixed) using the Research Diagnostic Criteria for TMD (RDC/TMD) Axis I guidelines for assessment of TMD signs and symptoms. Three psychometric instruments were used to assess the psychopathologic profile of the TMD subgroups. Patients' state and trait anxiety were assessed using the State-Trait Anxiety Inventory (STAI-S, STAI-T), depression was measured with the Center for Epidemiological Studies Depression Scale (CES-D), and psychosocial functioning was evaluated using the Global Disability Scale (Glo.Di.S). The three TMD groups were compared with Kruskal-Wallis test followed by pairwise Mann-Whitney tests relative to the psychometric scores. Statistical analyses were performed with SPSS 15.0 software. Results: No significant differences were detected among the different TMD groups in the three psychometric scales; STAI-T, CES-D, Glo.Di.S (P > .05). When the psychometric scale of state anxiety (STAI-S) was considered, significant differences were revealed between the myogenous and the arthrogenous pain groups (P = .008) and also between the mixed and the arthrogenous groups (P < .001). Conclusion: These findings suggest that the psychopathologic profile is not related to the location of pain in TMD patients. However, anxiety was found to be higher in TMD patients with myogenous pain alone or combined with arthrogenous pain compared to those with only arthrogenous pain.

The aim of this study was to identify mechanical complications associated with Nobel Biocare's angled screw channel (ASC) restorations following provision of the definitive crown. All ASC restorations provided between 1 January 2014 and 19 January 2016 were identified. Patients' clinical records were reviewed for demographic details, implant characteristics, occlusal considerations, and complications. A total of 84 implants placed in 60 patients were included. Three patients (4%) returned with mechanical complications, but the majority (n = 81; 96%) had no recorded complications. Long-term follow up is needed, but ASC restorations appear to offer a reliable and retrievable alternative to cement-retained restorations.

Purpose: This retrospective study compared posterior mandibular residual ridge resorption with two different retentive mechanisms for overdentures after 7 years. Materials and Methods: A convenience sample of 18 edentulous men was assigned to one of two equal groups. Two implants were placed in the mandibular canine areas for each patient using the conventional two-stage surgical protocol, and the implants were splinted with a round bar 3 months later. New mandibular overdentures were then connected to the bars with clips (clip-retained overdentures, CR group) or resilient liners (resilient liner-retained overdentures, RR group). Posterior mandibular ridge resorption (PMRR) was recorded using proportional measurements and posterior area index (PAI) on panoramic radiographs taken immediately after overdenture insertion (T0) and 7 years later (T7). A linear regression model was used to verify the relationship between PAI and the following considerations: attachment type, age, initial mandibular ridge height, period of mandibular edentulism, number of previously worn dentures, and relining events. Results: After 7 years, the RR group demonstrated a significantly (P = .014) higher change in PAI (0.11 ± 0.02) than the CR group (0.06 ± 0.04). The average PMRR for each mm of posterior mandibular ridge was 0.79 mm (0.11 mm/year) in the CR group and 1.4 mm (0.2 mm/year) in the RR group. Attachment type, initial mandibular ridge height, and relining times were significantly correlated with change in the PAI (P = .004, P = .035, and P = .045, respectively). Conclusion: Within the limitations of this preliminary study's design, it was observed that following a 7-year period of use, resilient liner attachments for bar/implantretained overdentures appear to be associated with greater posterior mandibular ridge resorption when compared to clip attachments.

Digital impressions can be a useful option that reduces patient discomfort and simplifies clinical procedures such as accurate impression recordings. In this report, a patient with a partial maxillectomy was managed with a metal frame fabricated from a digital impression through an intraoral scanner. The final impression employed the altered cast technique for the fabrication of the obturator.

Purpose: This systematic review evaluated treatment outcomes for mandibular mini-implant- retained overdentures (MMIOs) in terms of (1) implant survival rate, (2) peri-implant marginal bone loss, (3) prosthodontic maintenance and complication occurrence, and (4) patient satisfaction. Materials and Methods: Pertinent literature published in English before October 12, 2015 was identified using a MEDLINE and EMBASE search strategy and hand searching of relevant journals. Inclusion and exclusion criteria were applied to the titles and abstracts and subsequently to the full text of included studies. A total of 16 articles were included, from which qualitative and quantitative data were extracted for analysis. Results: Of the 16 evaluated articles, 5 were randomized controlled trials, 8 were prospective studies, and 3 were retrospective studies. The follow-up time range from implant placement was 1 to 6 years, and only four studies included more than 3 years of follow-up. The mini-implant survival rate ranged from 86.9% to 100%. Mean marginal bone resorption was 0.28 to 1.2 mm after 1 year of loading. Of the 16 studies, 5 reported prosthodontic maintenance and complications, and all included studies showed significant improvement in patient satisfaction. Conclusion: Despite the limitations of this systematic review, particularly the short follow-up periods, the results suggest that MMIOs showed predictable results regarding implant survival rates, marginal bone resorption, and patient satisfaction.

Purpose: The purpose of this study was to fabricate a prototype nonmetal clasp denture using computer-aided design/computer-assisted manufacture (CAD/CAM) technology. Materials and Methods: A partially edentulous mandibular working cast was scanned using an optical scanner. A sectional denture separated by two parts was designed on the scanned cast. These parts were milled and combined, and adhered using an adhesive luting agent. Results: The completed denture was delivered on the working cast and provided an excellent level of fitness. Conclusion: A prototype nonmetal clasp denture could be fabricated using CAD/CAM technology.

Oculo-dento-digital dysplasia (ODDD) is a congenital disorder manifesting with multiple phenotypic abnormalities involving the face, eyes, teeth, and limbs in addition to neurologic symptomatology. This report aims to present a female patient with ODDD who was referred due to extensive oral restorative needs. The presence of hypoplastic enamel triggered further evaluation. Characteristic facies with hypoplastic alae nasi and syndactyly offered greater insight into the phenotype of the syndrome. Clinical suspicion was confirmed by genetic sequencing revealing heterozygous mutation in GJA1. It is important to be aware of genetic disorders associated with characteristic dental malformations to offer appropriate counseling and treatment.

This study evaluated the effect of implant number and location on strain around the implant and force transferred to the palate in maxillary implant overdentures (IODs), including two locators attached bilaterally in the canine region (IOD 2), four locators attached bilaterally in the canine and premolar regions (IOD 4CP), four locators attached bilaterally in the canine and molar regions (IOD 4CM), and six locators attached bilaterally in the canine, premolar, and molar regions (IOD 6). As the implant number increased, strain around the implant regions increased, whereas force transferred to the palate decreased under loading. However, the differences were small between IOD 4CM and IOD 6, suggesting identical biomechanical effectiveness.

Purpose: Precisely designed jaw reconstruction rehabilitation (JRR) is important to the integrity of the jaw structure and oral functions. Advanced three-dimensional (3D) digital surgical design and simulation (SDS) techniques have the potential to reduce time to reconstructive and dental treatment completion, thereby promoting early functional oral rehabilitation. This study investigated the use of SDS in JRR procedures. Materials and Methods: A retrospective chart review was conducted on adult head and neck tumor (HNT) participants who completed JRR treatment with a fibular free flap (FFF) reconstruction. Two treatment approaches, advanced 3D SDS technique (with-SDS) and conventional, nondigitally planned technique (without-SDS), included the use of osseointegrated implants. Data were collected from adult patients treated between January 2000 and March 2014 at the Institute for Reconstructive Sciences in Medicine (iRSM). Participants were excluded if they underwent a bone-containing augmentation to the FFF reconstruction. The without-SDS group underwent a conventional, nonguided FFF reconstruction followed by nonguided implant placement. The with-SDS group underwent a guided FFF reconstruction with guided implant placement during the reconstructive surgery. The outcome measures included implant utilization (ratio of implants placed to connected) and time to prosthetic connection after FFF reconstruction. Mann-Whitney U test was used to analyze the data. Results: The digital SDS technique (with-SDS) group completed prosthetic treatment with a significantly higher utilization of implants as well as a significantly shorter time to prosthetic delivery. Conclusion: SDS allows an interdisciplinary treatment team to work together to create a virtual plan that leads to greater efficiency in patient treatment time and utilization of dental implants.

Purpose: The aim of the present study was to describe personality traits of a sample of Spanish adults, identify the main sociodemographic factors related to personality, and assess the influence of these traits on healthy dental habits. Materials and Methods: A crosssectional design was used with 235 subjects, all of Spanish nationality and aged between 18 and 80 years, with a minimum educational level (ie, they had completed only the minimum obligatory schooling), ensuring that none of the subjects had any psychologic disturbance. The data on five personality dimensions were recorded. Sociodemographic and behavioral standard scores (z) were studied for each personality dimension, and the scores were related to the other variables studied. Results: A significant linear correlation was observed between the z scores of the personality factors and the sociodemographic and behavioral characteristics. The men had personalities with significantly less neuroticism, less openness, less agreeableness, and less conscientiousness than the women. In behavioral terms, those who brushed more than once a day were more agreeable (0.1 ± 0.9) than those who only brushed once a day (−0.2 ± 1.2), and smokers had higher mean scores for extroversion (0.3 ± 0.9) than did nonsmokers (−0.1 ± 1.0). Conclusion: The most developed personality traits in this sample, as in the reference population, were conscientiousness (123.1 ± 22.9 points) and agreeableness (119.2 ± 19.1 points). The main sociodemographic factors of personality were found to be age and sex. Moreover, it was observed that certain personality dimensions were linked to smoking and tooth brushing habits.

Purpose: The aim of this study was to correlate the location of the mental foramen and overlying teeth and apply these observations to posterior prosthetic teeth selection in a group of Egyptian edentulous patients. Materials and Methods: Retrospective cone beam computed tomography data from 40 dentate and 40 edentulous patients scanned with radiopaque denture duplicates were compared in relation to mental foramen position. Results: The probability of locating the mental foramen opposite the first premolar was higher in dentate patients, while finding it opposite the first molar was higher in edentulous patients. Conclusion: Selected posterior teeth size for the selected Egyptian edentulous patients might be slightly smaller than for dentate patients.

When a screw-retained implant prosthesis is removed, a click is heard and a slight axial shift is felt, indicating the screw has been fully removed from the retaining thread. This common observation has never been described in the literature. This article describes the click, and it is proposed it be termed thread-skip.

Purpose: The aim of this study was to compare the marginal fit of cobalt-chromium crowns fabricated using conventional casts and computer-aided design/computer-assisted manufacturing (CAD/CAM) techniques at three stages of production: metal coping, after porcelain firing, and after cementation. Materials and Methods: A total of 80 metal-ceramic crowns were fabricated using four different techniques: lost wax casting, milling, laser sintering, and milling of a presintered metal block. Marginal fit was measured at each manufacturing stage. Results: The porcelain firing stage improved marginal fit. CAD/CAM techniques resulted in better marginal fit than did conventional casting techniques at all manufacturing stages. Conclusion: CAD/ CAM techniques improve marginal fit.