The International Journal of Prosthodontics, 01/2013

The aim of this prospective clinical split-mouth study was to investigate the longterm performance of pressed and computer-aided design/computer-assisted manufacture (CAD/CAM) all-ceramic partial-coverage restorations (PCRs). Twentyfive patients were restored with 40 lithium disilicate pressed PCRs (IPS e.max-Press, Ivoclar Vivadent) and 40 leucite-reinforced glass-ceramic CAD/CAM PCRs (ProCAD, Ivoclar Vivadent). All restorations were placed in vital first or second molars. The 7-year Kaplan-Meier survival rate was 100% for pressed PCRs and 97% for CAD/ CAM PCRs. Both systems showed significant deterioration over time in all modified United States Public Health Service criteria. Increased surface roughness and impaired color match were significantly more prevalent with pressed PCRs. Based on the 7-year data, both all-ceramic systems can be considered reliable treatment options for posterior PCRs.

Purpose: The aim of this study was to qualitatively review the literature regarding occlusal schemes for complete dentures. Materials and Methods: An electronic search was executed using PubMed (MEDLINE) with the aid of Boolean operators to combine the following terms: "complete denture," "occlusion," "balanced," "lingualized," "anatomic," "flat," "monoplane," and "canine." The search was limited to English peer-reviewed articles published up to January 2012. The literature search was supplemented by manual searching of relevant journals and the reference lists of selected articles. Results: A total of 565 articles were retrieved; however, only 12 articles met the inclusion criteria. The included studies evaluated the effects of posterior tooth morphology/arrangement and lateral occlusal guidance. In relation to morphology, the posterior teeth were either anatomical or flat. The posterior tooth arrangements showed conventional bilaterally balanced occlusion (CBBO), lingualized bilaterally balanced occlusion (LBBO), or monoplane occlusion (MO). The lateral occlusal guidance involved either balanced occlusion or anterior tooth-guided occlusion (ATGO). Conclusions: Within the limitations of this review, it can be concluded that anatomical teeth arranged in CBBO or LBBO are preferable to flat teeth arranged in MO. This is primarily related to patient acceptance. ATGO can also be considered for complete dentures.

Purpose: This study aimed to explore the relationships among tooth replacement, number of present natural teeth, and sociodemographic and behavioral factors in an adult population in Bulgaria. Materials and Methods: Quota sampling was used to recruit 2,531 dentate subjects aged 20 years and over from the capital city and four main urban centers, four towns, and seven small towns and villages of Bulgaria. Potential candidates for tooth replacement were classified as having functional dentitions (26 to 27 or 20 to 25 natural teeth present) or subfunctional dentitions (16 to 19 or 2 to 15 natural teeth present), not including third molars. Multiple logistic regression analyses were performed to determine the associations between tooth replacement and the factors of interest. Results: Of the included subjects, 37% presented with tooth replacement, while 19% presented with fewer than 20 natural teeth. Molars were replaced significantly less often (P = .017) than premolars and anterior teeth. The presence of tooth replacement was more likely in subjects with 2 to 15 teeth (odds ratio: 1.62) and less likely in subjects with 26 to 27 teeth (odd ratio: 0.29), but no significant difference was detected between subjects with 16 to 19 and 20 to 25 teeth. Tooth replacement was associated with age, occupational status, frequency of dental visits, and toothbrushing habits. Conclusions: In this Bulgarian population, the variables number of present teeth, age, dental visits, and toothbrushing were relevant factors with respect to tooth replacement. The cutoff value of 20 teeth did not discriminate high-risk from low-risk subjects.

Fifteen edentulous patients with overdentures supported by two implants in the mandibular canine regions received periodontal therapy using both hand instrumentation with Teflon curettes and a glycine-based airflow system. Periodontal probing depth (PPD), bleeding on probing (BOP), and bacterial content (BC) within the gingival sulcus were analyzed. A significant effect modification of the glycine airflow with respect to time was found for PPD (P = .01), BOP (P .001), and BC (P = .004), which were treated as ordered categorical variables. Glycine airflow may be more effective than Teflon curettes for the maintenance of periimplant soft tissues.

Purpose: The effect of gingival coverage by removable partial dentures (RPDs) on bacterial accumulation has not been sufficiently established. The aim of this study was to evaluate the periodontal and microbiologic reactions to mandibular major connectors. It was hypothesized that the use of a lingual plate increases the risk of periodontal disease. Materials and Methods: Fourteen subjects (mean age: 69.0 years) received oral hygiene instructions and ultrasonic debridement prior to examination. Each subject received an experimental RPD incorporating either a lingual bar or lingual plate for the first 8 weeks and was then switched to the other option for the next 8 weeks. Clinical parameters (Plaque Index, Gingival Index, probing depth, and tooth mobility) were recorded. Subgingival plaque samples were collected from the periodontal pocket in the test site to measure the colonization of periodontal pathogens after the use of each denture. Results: The mean probing depth was significantly greater after use of the lingual plate compared to the lingual bar (P .05), whereas the type of connector did not affect the levels of any of the microbial species. All subjects that exhibited at least one bacterial species showed smaller numbers of microorganisms at the second examination than at the first. Conclusions: The lingual cervical coverage did not precipitate the accumulation of anaerobic microorganisms, although it could potentially induce gingival inflammation. The results suggest that a lingual plate can be used as safely as a lingual bar if oral and denture hygiene are carefully monitored.

This case report describes a method to produce one final master cast for the simultaneous prosthetic treatment of implants and natural teeth in a single arch. After tooth preparation, a first impression was used to fabricate electroformed crown frameworks. In the next appointment, the crown frameworks were seated and collected with the implant transfer copings in a single-phase fixation impression, which was used to fabricate a final master cast. This procedure divides the treatment process into distinct steps, leading to a faster and less challenging workflow.

This study investigated the influence of implant abutment and screw access channel modification on the retention of copings. Titanium abutment access openings were either left open or modified by placing two vent holes 3 mm from the occlusal edge and 180 degrees apart. Access openings sealed with a resin material were used as controls. Metal copings were cemented and subjected to tensile testing until failure. Access openings with two vent holes resulted in significantly higher mean retention values compared to the opened or sealed screw access groups (P .05). Cement flow was affected by the internal vent, which increased the area of cementabutment contact.

Purpose: This study aimed to review the current state of the techniques and materials used to rehabilitate maxillofacial defects. Materials and Methods: The MEDLINE and EMBASE databases were searched for articles pertinent to maxillofacial prostheses published from January 1990 to July 2011. The main clinical stages were the subject of analysis. Results: A multidisciplinary approach is preferred when rehabilitating maxillofacial defects. Surgical reconstruction can be used for smaller defects, but larger defects require a prosthesis to achieve an esthetic rehabilitation. Implantretained prostheses are preferred over adhesive prostheses. Silicone elastomer is currently the best material available for maxillofacial prostheses; however, longevity and discoloration, which are greatly influenced by ultraviolet radiation, microorganisms, and environmental factors, remain significant problems. In the near future, the widespread availability and cost effectiveness of digital systems may improve the workflow and outcomes of facial prostheses. Patients report high satisfaction with their prostheses despite some areas that still need improvement. Conclusions: Maxillofacial prostheses are a reliable treatment option to restore maxillofacial defects and improve quality of life. Significant progress has been made in the application of implants for retention and digital technology for designing surgical guides, suprastructures, and craniofacial prostheses. Further improvements are necessary to enhance longevity of prostheses.

Purpose: The purpose was to assess and compare self-reported oral health and oral and general health related quality of life (OHRQoL and HRQoL) in two groups of edentulous adults who reported dissatisfaction with their mandibular dentures, and who were treated with a conventional relining of this denture or by having it converted into an implant-retained one. Materials and Methods: Sixty subjects were randomly allocated into two equal groups, a relined conventional denture (RCD) group and an implant-retained overdenture (IOD) group. Data on demographics, oral health, OHRQoL, and HRQoL were recorded by means of a self-administered questionnaire at baseline, 3 months, and 2 years. Results: Fifty-four subjects completed the protocol, 28 in the IOD-group and 26 in the RCD-group. The IOD group reported significant improvement in oral health and Oral Health Impact Profile (OHIP-20) sum score and all its domains after 3 months. The improvements remained stable at the 2-year control. The RCD group reported almost no significant improvements. Neither group reported improved HRQoL. Conclusion: The results of this study support the findings from other RCT studies that to implant-retain the mandibular denture significantly improves self-reported oral health and OHRQoL. This treatment modality should be a minimum standard of care in complete denture wearers dissatisfied with their mandibular denture.

Heat-cured acrylic resin specimens were polished using either conventional laboratory polishing, sandpaper, or three commercial chairside kits. The surface roughness of the polished specimens was measured with a contact profilometer. Scanning electron microscopy was used to obtain microphotographs of the polished surfaces. Laboratory polishing produced the smoothest surfaces in all cases, while sandpaper application produced the roughest. Use of the chairside polishing kits resulted in significantly rougher surfaces compared to those produced by laboratory polishing. Nonetheless, polishing of trimmed denture bases using chairside polishing kits is an effective alternative procedure for cases in which the laboratory procedure is not applicable.

The aim of this preliminary in vitro study was to compare the retentiveness of a luting agent designed for use with dental implants to luting agents designed for use with tooth-retained restorations. The following luting agents were tested: (1) implant cement, (2) resin-bonded zinc oxide-eugenol cement, (3) zinc phosphate cement, (4) zinc polycarboxylate cement, and (5) glass-ionomer cement. After cementation, each sample was subjected to a pull-out test using a universal testing machine, and the loads required to remove the crowns were recorded. The mean values and standard deviations of cement failure loads were analyzed using analysis of variance and the Bonferroni test. The mean cement failure loads (N) were 333.86 ± 18.91 for implant cement, 394.62 ± 9.76 for resin-bonded zinc oxide-eugenol cement, 629.30 ± 20.65 for zinc phosphate cement, 810.08 ± 11.52 for zinc polycarboxylate cement, and 750.17 ± 13.78 for glass-ionomer cement. The retention provided by polycarboxylate cement was significantly greater than that of all other luting agents; the implant cement showed the lowest retention values. These preliminary in vitro observations need to be confirmed under conditions that more closely approximate the clinical environment.

The aim of this study was to evaluate the effect of the spray pattern, water flow rate, and cutting position on the cutting efficiency of high-speed dental handpieces. One- and three-port high-speed handpieces were selected. Cutting efficiency (mm/s) in different cutting positions was evaluated in vitro on machinable ceramic underwater flow rates of 15, 25, and 35 mL/min. Statistical analysis revealed significant differences in cutting efficiency for the various cutting positions and flow rates. The authors recommend multiport handpieces with a flow rate greater than 30 mL/min for use in clinical practice, especially during groove cutting.