The International Journal of Prosthodontics, 04/2015

The aim of this study was to evaluate the changes in the masticatory functions of complete dentures before and after the insertion of a LOCATOR attachment. The mixing ability index with a two-colored paraffin wax cube was used to quantify masticatory performance. In addition, degree of satisfaction with the treatment was assessed using a visual analog scale. The mixing ability index for the implant-retained overdentures and the complete dentures were calculated (−0.03 ± 1.38 and −2.10 ± 1.57, respectively), as were the visual analog scales of the implant-retained overdentures and the complete dentures (8.9 ± 1.5 and 4.3 ± 1.7, respectively). The paired t test revealed significant improvements (P .001).

Purpose: The aim was to report on oral rehabilitation of a boy with X-linked hypohidrotic ectodermal dysplasia (XLHED) and anodontia of the mandible between ages 3 and 33 years where treatment involved dental implants and oral care management by a multidisciplinary team of specialists. Materials and Methods: This case history report describes the clinical management of a boy born in 1979 with XLHED and anodontia of the mandible. Two implants were successfully placed in the anterior region of the mandible in 1985. Genetic analysis later verified the diagnosis by confirming a mutation in the EDA gene. The case description was based on review of the patient records and assessment of orofacial function. Results: The patient had satisfactory orofacial appearance and function throughout his youth. He is still caries-free at age 33 and has experienced only minor oral complications. Dental management began at age 3, when he received a maxillary removable dental prosthesis. At age 7, he received a mandibular implant-supported overdenture. After two more implants in the mandible and orthodontic treatment in the maxilla, his oral rehabilitation was completed at age 22 with maxillary tooth-supported and mandibular implant-supported fixed dental prostheses. Regular follow-ups provided supervision of oral hygiene, caries prevention, and prosthetic maintenance. Conclusion: This long-term follow-up of a child with XLHED and anodontia in the mandible supports the use of dental implants, with consideration given to the dense bone quality associated with the diagnosis, to establish good orofacial function and appearance from childhood onward.

Purpose: Despite the high fracture strength of modern dental core ceramics, fractures are a common cause of clinical failures. The aim of this study was to use a clinically relevant test method to evaluate the effect of the curvature of the cervical crown margins on load at fracture. Materials and Methods: Thirty zirconia crowns and 30 glass-ceramic crowns were produced for three premolar preparations with variation in the approximal crown margin curvature: low curvature (r = 12 mm), moderate curvature (r = 2.5 mm), and high curvature (r = 1.5). The crowns were loaded until fracture with a method that mimics clinical fracture modes. Results: Statistically significant differences were found among both crown margin curvature and material groups (P .001). Most fractures originated from pre-existing flaws. Conclusion: A moderate to low curvature of the crown margins increases crown strength compared with a high curvature.

The objective of this preliminary study was to determine if the occlusal contact surface registered with an articulating paper during fixed prosthodontic treatment was contained within the area marked on a thicker articulating paper. This information would optimize any necessary occlusal adjustment of a prosthesis' veneering material. A convenience sample of 15 patients who were being treated with an implant-supported fixed singleunit dental prosthesis was selected. Occlusal registrations were obtained from each patient using 12-μm, 40-μm, 80-μm, and 200-μm articulating paper. Photographs of the occlusal registrations were obtained, and pixel measurements of the surfaces were taken and overlapped for comparison. The results showed that the thicker the articulating paper, the larger the occlusal contact area obtained. The differences were statistically significant. In all cases, the occlusal registrations obtained with the thinnest articulating paper were contained within the area marked on the thickest articulating paper. The results suggested that the use of thin articulating papers (12-μm or 40-μm) can avoid unnecessary grinding of veneering material or teeth during occlusal adjustment.

Purpose: To determine if there are objective changes in lower facial height and subjective changes in facial esthetics with incremental increases in occlusal vertical dimension in dentate subjects. Materials and Methods: Twenty subjects of four different races and both sexes with a Class I dental occlusion had custom diagnostic occlusal prostheses (mandibular overlays) fabricated on casts mounted on a semi-adjustable articulator. The overlays were fabricated at 2-mm, 3-mm, 4-mm, and 5-mm openings of the anterior guide pin of a semi-adjustable articulator. Direct facial measurements were made between pronasale and menton on each subject while wearing the four different overlays. Thereafter, two digital photographs (frontal and profile) were taken for each subject at maximum intercuspation (baseline) and wearing each of the four mandibular overlays. The photographs of eight subjects were standardized and displayed in a random order to 60 judges comprising 30 laypeople, 15 general dentists, and 15 prosthodontists. Using a visual analog scale, each judge was asked to rate the facial esthetics twice for each of the 80 images. Results: For objective changes, although an anterior guide pin-lower facial height relationship of 1:0.63 mm was observed, the findings were not correlated (P > .20). For subjective changes, the visual analog scale ratings of judges were uncorrelated with increases in anterior guide pin opening up to 5 mm, irrespective of the judge's background status or the sexes of the judges or the subjects (P > .80). Conclusions: Incremental increases in anterior guide pin opening up to 5 mm did not correlate to similar increases in lower facial height. Additionally, it made no difference in a judge's evaluation of facial esthetics irrespective of the judge's background status (layperson, general dentist, or prosthodontist) or sex.

This study investigated subgingival peri-implant biofilm formation on four luting agents (Kerr TempBond, Harvard Dental Harvard Cement, 3M ESPE RelyX Unicem, and Kuraray Panavia F 2.0) under realistic in situ conditions. Samples of the luting agents were positioned in the subgingival area of healing abutments, and the biofilm accumulation on the samples at the interface between luting agent and titanium and on the smooth titanium surface was investigated using scanning electron microscopy. In comparison to plane titanium surfaces, interfaces between implant abutment, cement, and suprastructure showed an increased bacterial accumulation and should therefore be regarded as predisposing substrates for peri-implant biofilm formation.

Purpose: Ultrasonography has been extensively explored in dentistry because of its several diagnostic advantages. The purpose of this study was to determine the thickness of the maxillary attached gingiva with the use of a high-frequency ultrasound in subjects with sex-, age- and smoking-related differences. Materials and Methods: A total of 100 healthy subjects (70 women and 30 men, age range: 18 to 55 years) were included. A special B-scan unit was used to measure the soft tissue thickness in the buccal and palatal attached gingiva in the maxillary arch. Aquasonic 100 Ultrasound Gel (Parker Laboratories) was used as coupling medium. Student t test was used for statistical analysis of the subgroups with different parameters with significance set at P .05. Results: A total of 2,734 measurements showed that male nonsmokers have a significantly thicker fixed gingiva than nonsmoking women and that age does not seem to have great influence on the thickness of the gingiva. Smoking had a significant effect, but only on the oral maxillary gingival tissues of women. The palatal gingiva was found to be significantly thicker in female smokers than in nonsmoking females. Conclusions: Measurement of gingival thickness for different purposes using a B-scan ultrasonic device appears to be a reliable method. Sex- and smoking-related differences in the gingival thickness exist only on the palatal side among women.

This study assessed the use of the commercial artificial teeth setup device Staub Cranial System (Neu-Ulm) in Asian subjects. Fourteen completely dentate Thai volunteers were randomly recruited. Study casts (control group) and duplicated casts (experimental group) of all subjects were prepared. Artificial teeth were replaced on duplicated casts according to the manual. Computed tomography scans of all casts were performed. Intercanine width, intermolar width, incisocervical length, and occlusal plane were investigated. The length of the natural mandibular left central incisor was smaller than the reconstructed one. The reconstructed occlusal plane was more parallel to the hamular-incisive papilla plane than that of the control group.

This study compared the distribution of forces in relation to the area covered by the denture base. Seven participants were fitted with a loading device on the maxilla and were guided to bite on an experimental mandibular denture. The denture base was progressively shortened from full coverage of the retromolar pad. One-way analysis of variance (P .05) was performed, and no significant difference was found among the four denture base lengths in relation to force distribution. Within the limitations of this study, the authors conclude that the area covered by the retromolar pad has little influence on force distribution during loading.

Purpose: The aim of this study was to evaluate the behavior of hard and soft tissue around implants with different surface treatments. Materials and Methods: Eight patients were identified for this study. Each patient received at least 2 implants (1 control, 1 test) into an edentulous quadrant, for a total of 10 pairs of implants. Two types of implants were used: hybrid implants (control) with a dual acid-etched surface in their apical portion and a machined coronal part, and test implants with an acidetched surface throughout their entire length. Standardized periapical radiographs were taken at baseline, 3 months, 6 months, and 1 year post implant placement and then annually until the 6-year follow-up. Bleeding on probing (BOP) and Plaque Index (PI) were recorded annually. Probing depth (PD) was recorded at the 6-year follow-up. Results: Moderate crestal bone remodeling was observed during the 1-year postimplant placement evaluation (P = .001), and test implants revealed smaller marginal bone resorption (P = .030). No significant changes in bone level were observed between the 1-year and the 6-year follow-up appointments, and a significantly smaller bone resorption was found at test implants. No statistically significant differences in bone resorption were found between maxilla and mandible. No statistically significant differences were detected between test and control implants for BOP, PI, or PD. Conclusions: The preliminary results suggest that implant surface characteristics might affect the bone remodeling phase subsequent to the surgical trauma. However, once osseointegration was established, implant surfaces did not affect bone maintenance over time. Implant surfaces did not affect soft tissue behavior. The results of this pilot study need to be confirmed in a study with a larger sample size and over a longer time frame.

A preliminary tensile test was performed to evaluate the mechanical properties of cobalt-chromium (Co-Cr) alloys fabricated by three new manufacturing processes: metal milling, milling for soft metal, and rapid prototyping (n = 6). For comparison, the three alloy materials were also used to fabricate specimens by a casting procedure. In all groups tested, the proof strength and elongation were over 500 MPa and 2%, respectively. The milled soft alloy in particular showed a substantially greater elongation, whereas the alloy fabricated by rapid prototyping exhibited a higher proof strength.

This preliminary study investigated the influence of different oral prosthodontic interventions on quality of life related to voice and oral health in elderly people and the relation between these conditions. Forty-five elderly people who had completed prosthodontic rehabilitation treatments were divided into three groups according to dental conditions and answered two protocols: voice-related quality of life and oral health impact profile. Despite the small sample size, the elderly people in this study presented no differences between the groups and showed a relationship between oral and vocal health aspects.

Purpose: The objective of this study was to determine the oral health-related quality of life in state institutionalized older adults and correlate it to their oral health status. Materials and Methods: A group of 278 older adults (average age: 83.5 ± 6.5 years) from 9 state institutions in Malta was randomly selected. Participants were clinically examined and answered three questionnaires (Oral Health Impact Profile [OHIP-14], Geriatric Oral Health Assessment Index [GOHAI], and Denture Satisfaction). Results: Oral health-related quality of life measurements were significantly associated with pocket depth (OHIP-14 and GOHAI, P .05); decayed, missing, or filled teeth (OHIP‑14 and GOHAI, P .05); carious teeth (OHIP-14 and GOHAI, P .05); number of missing teeth (OHIP-14 and GOHAI, P .05); and maxillary and mandibular dentures (OHIP‑14 and GOHAI, P .0001). Denture satisfaction was associated with denture age (P = .010) and types of prostheses (P .05). Conclusion: Institutionalized older adults have high levels of oral disease. Although oral health-related quality of life is generally good, those participants with a poorer oral health-related quality of life had significant associations with poor oral health. However, the extent varies with the individual's perception of good health.

Prosthodontically driven biomechanical considerations are essential for longterm successful outcomes in dental implant therapy. Correct protocols seek to preclude potential consequences associated with functional and parafunctional occlusal overload such as screw loosening, component fracture, compromised marginal bone maintenance, and the integrity of the induced osseointegration response. Other concerns also need to be addressed, more especially when other implants are selected, for example: bridge insertion torque (BIT) in cases of immediate loading, cantilever length-anteroposterior spread ratio (CL-AP), overall crown-to-implant ratio (oCIR), total bone-to-implant surface area (tBICA), and the status of the opposing dentition. In spite of promising clinical results, evidencebased clinical protocols demand that such biomechanical limits still need to be determined.

The purpose of this preliminary in vitro study was to evaluate the effect of an opaque layer and application of resin composite in dual colors on the ΔE values of resin composites used to fill access openings of screw-retained implant restorations. Sixty cylindrical nickel-chromium metal molds with a central channel simulating a posterior screw-retained, implant-supported, porcelain-fused-to-metal crown were cast. Access openings were filled with combinations of opaquer, enamel composite (A2E), dentin composite (A2B and A3B), and resilient composite. ΔE values differed significantly among the groups (P .01). The combination of opaque layer and dual color resin composites of shades A2E and A3B resulted in significantly lower ΔE values than the other groups (P .01).

Purpose: The purpose of this noninferiority study was to determine whether removable or implant-supported fixed dental prostheses restored patients' abilities to preoperative levels after cancer removal in the mandible. Materials and Methods: Ten patients who had undergone mandibular resection to remove cancer and subsequent reconstruction with microvascularized free fibula flaps were examined in this study. Five patients were rehabilitated with removable prostheses and five received implant-supported fixed prostheses. Health-related quality of life was evaluated using the Head and Neck (H&N30) questionnaire. Kruskal-Wallis nonparametric analysis of variance and Tamhane's T2 test were used to analyze results in comparison with a control group composed of 10 subjects with Class I natural dentition. Results: Masticatory efficiency among the three groups of patients differed significantly (P = .003); in particular, that of the patients who received removable prostheses was not inferior to that of the control subjects (P = .019). Analysis of responses to the Head and Neck module of the Quality of Life Questionnaire showed no significant difference between patients with fixed dentures and patients with removable dentures. Conclusions: There is no apparent difference in quality of life between patients using implant-supported fixed prostheses and those using removable prostheses. Regarding masticatory efficiency, when feasible, the use of implantsupported fixed prostheses is recommended in patients who have undergone free fibula flap surgery, although the removable prostheses also were not inferior in patients who underwent no surgery.

This survey of German dental schools sought to gain insight into the present prosthetic treatment concepts and their application in student and postgraduate education, as well as to compare the results to those from an identical 2002 survey. A questionnaire, based on this issue, was sent via email to the chairpersons of all prosthetic departments of the German dental schools, and 93.1% of the departments completed the questionnaire. Within the limitations of this survey, almost all treatment concepts for the reduced dentition are taught intensively at dental schools in Germany while some therapy forms are preferred.

This study analyzed the shear strength and fracture characteristics of the interface between zirconia samples and their veneering ceramic compared with a metalceramic and a lithium disilicate glass-ceramic control group together with an assessment of the possible relationship between the fracture characteristics and the recorded shear strength. The greatest shear strengths corresponded to the lithium disilicate glass-ceramic control group followed by the metal-ceramic control group, with lesser strengths in the zirconia groups. Since the fractographic study showed cohesive-type failure to predominate in the zirconia samples, it is concluded that improvements are needed in the veneering ceramic and liner used in zirconia restorations.