Quintessence International, 01/2015

Objective: To investigate the accuracy of conventional and digital impression methods used to obtain full-arch impressions by using an in-vitro reference model. Method and Materials: Eight different conventional (polyether, POE; vinylsiloxanether, VSE; direct scannable vinylsiloxanether, VSES; and irreversible hydrocolloid, ALG) and digital (CEREC Bluecam, CER; CEREC Omnicam, OC; Cadent iTero, ITE; and Lava COS, LAV) full-arch impressions were obtained from a reference model with a known morphology, using a highly accurate reference scanner. The impressions obtained were then compared with the original geometry of the reference model and within each test group. Results: A point-to-point measurement of the surface of the model using the signed nearest neighbour method resulted in a mean (10%−90%)/2 percentile value for the difference between the impression and original model (trueness) as well as the difference between impressions within a test group (precision). Trueness values ranged from 11.5 μm (VSE) to 60.2 μm (POE), and precision ranged from 12.3 μm (VSE) to 66.7 μm (POE). Among the test groups, VSE, VSES, and CER showed the highest trueness and precision. The deviation pattern varied with the impression method. Conventional impressions showed high accuracy across the full dental arch in all groups, except POE and ALG. Conclusions: Conventional and digital impression methods show differences regarding full-arch accuracy. Digital impression systems reveal higher local deviations of the full-arch model. Digital intraoral impression systems do not show superior accuracy compared to highly accurate conventional impression techniques. However, they provide excellent clinical results within their indications applying the correct scanning technique. Keywords: CAD/CAM, conventional impression, digital impression, full-arch dental impression, precision, trueness

Objective: This study aimed to determine the survival rate and prevalence of biologic and technical complications associated with single-tooth implants with all-ceramic abutments in the anterior region. Method and Materials: A total of 33 patients were restored with 50 anterior implants and temporarily luted all-ceramic crowns on prefabricated zirconia abutments. All of the patients subsequently received annual supportive maintenance; 27 patients (18 women, 22-74 years) with 42 implants participated in the final maintenance visit and were included in the study (follow-up 78.1 ± 27.0 months). The time-dependent survival rate (Kaplan-Meier) and the frequency of prosthetic complications (abutment fracture [AF], screw loosening [SL], fracture of veneering ceramics [VF], retention loss [RL]) and biologic complications (peri-implantitis) were calculated to determine the success rates. Results: No implant loss (implant-related survival rate 100%) but one abutment fracture occurred throughout the entire observation period; therefore, the survival rate of the superstructures (in situ criterion) was 97.6% (95% confidence interval [CI] 0.930- 1.000) after 7 years. Eleven restorations were affected by prosthetic complications: RL (n = 4), VF (n = 5), and SL (n = 2). Peri-implantitis was diagnosed for two implants (probing depth > 5 mm, bleeding on probing [BOP]/suppuration, and bone loss > 3 mm) (implant-related peri-implantitis rate 4.8%). No restoration required replacement due to complications. The success rate (event-free restoration) was 75.9% (95% CI 0.636- 0.882) after 7 years. Conclusions: Considering the calculated survival rate, the application of all-ceramic zirconia implant abutments in the anterior region can be recommended as a reliable therapy in private practice. Fractures of veneering ceramics were the most common prosthetic complication. Keywords: cement, ceramics, clinical studies, peri-implant infection, success, survival

Objectives: To characterize the physical characteristics of a new low abrasive erythritol powder (EPAP) and to evaluate its influence on the clinical and microbiologic parameters over a period of 6 months in patients undergoing supportive periodontal therapy (SPT). Method and Materials: Prior to the clinical application, the particle size and abrasion level of EPAP were compared to glycine air-polishing powder (GPAP) ex vivo. Subsequently, 40 chronic periodontitis patients previously enrolled in SPT were randomly assigned into two groups for the treatment with subgingival EPAP or repeated scaling and root planing (SRP). At baseline (BL), bleeding on probing positive (BOP+) sites with probing pocket depth (PPD) of ≥ 4 mm but no detectable calculus were defined as study sites. During SPT, these sites were either treated by EPAP or SRP at BL, 3, and 6 months (3M, 6M). When indicated, additional SRP was provided. Plaque Index, BOP, PPD, clinical attachment level (CAL), and subgingival plaque were evaluated at BL and 6M. Results: EPAP yielded lower abrasiveness and smaller particle sizes when compared to GPAP. In 38 patients completing the study, EPAP and SRP resulted in significant reductions of BOP% (EPAP, 40.45%; SRP, 42.53%), PPD (EPAP, -0.67; SRP, -0.68), and increase of CAL (EPAP, 0.48; SRP, 0.61) while at 6M no statistically significant between-group differences were observed (P > .05). Microbiologic evaluation revealed minor shifts in the composition of the subgingival biofilm without influence on periodontopathogenic bacteria. Conclusion: The subgingival use of EPAP by means of an air-polishing device may be considered safe and may lead to comparable clinical and microbiologic outcomes to those obtained with SRP. Clinical Relevance: The subgingival use of EPAP appears to represent a promising modality for the removal of subgingival biofilm during SPT. Keywords: air polishing, bleeding on probing, erythritol, hard tissue loss, supportive periodontal therapy

Objectives: Evaluate the antibacterial properties of three commercial collagen membranes for guided bone regeneration (GBR). Method and Materials: BioGide®, OsseoGuard®, and CopiOs® membranes were tested for antibacterial properties against Streptococcus sanguinis, Staphylococcus aureus, and Staphylococcus epidermidis using a direct contact test (DCT). Samples of each membrane, sized 5 × 2 mm, were fixed to the side wall of 6 wells in a 96-well microtiter plate. Bacterial suspension was placed on each sample. The plate was incubated at 37°C for 1 hour to allow suspension fluid evaporation. Fresh medium was added to each well and the plate was mixed. Non-contaminated membrane samples served as negative control. Bacterial growth was monitored spectrophotometrically at 650 nm for 24 hours. ANOVA and Tukey's comparison tests were used for the statistical analysis. Results: The presence of the membrane samples did not disrupt bacterial growth. However, the presence of OsseoGuard membrane accelerated bacterial growth rate of S sanguinis and S epidermidis as compared to the other two membranes and control samples (P .001), and of S aureus as compared to the control alone (P .001). Conclusions: The tested collagen membranes have no antibacterial properties. However, OsseoGuard presents a significant bacterial growth enhancement effect with possible significant clinical implications on the success of regenerative procedures around teeth and implants. Keywords: antibacterial, barrier, collagen, membranes, regeneration, resorbable

Objectives: The aim of this retrospective study was to evaluate the long-term outcomes of long-span fixed dental prostheses (LSFDPs) not meeting Ante's law. Method and Materials: This study is based on the data of 36 patients who received 41 LSFDPs. The mean survival time of the LSFDPs was calculated using the Kaplan-Meier technique. The influence of the factors (gender, localization, number of abutments, Kennedy Class, dentition of the opposing jaw) were analyzed (log-rank test and Cox regression; P .05). Results: During the observation period, 22.0% (n = 9) of the LSFDPs ceased to function. The calculated outcome probability after 3 years was 88.3%, and 57.4% after 5 years. The only significant difference in the mean survival time could be found in LSFDPs with two abutment teeth in comparison with LSFDPs with three and more abutment teeth. Although all of the patients were invited to an oral health and maintenance program regularly, only 13.8% attended. Conclusion: The results, taken together with data from the literature, indicate that the patient's compliance is a crucial factor in the successful implementation of a LSFDP, whereas other factors are of minor importance. Keywords: Ante's law, clinical study, fixed dental prosthesis, Kaplan-Meier analysis, prosthodontics, retrospective analysis

Objective: The aim of this cross-sectional study was to estimate bone loss of implants with platform-switching design and analyze possible risk indicators after 5 years of loading in a multi-centered private practice network. Method and Materials: Peri-implant bone loss was measured radiographically as the distance from the implant shoulder to the mesial and distal alveolar crest, respectively. Risk factor analysis for marginal bone loss included type of implant prosthetic treatment concept and dental status of the opposite arch. Results: A total of 316 implants in 98 study patients after 5 years of loading were examined. The overall mean value for radiographic bone loss was 1.02 mm (SD ± 1.25 mm, 95% CI 0.90- 1.14). Correlation analyses indicated a strong association of peri-implant bone loss > 2 mm for removable implant-retained prostheses with an odds ratio of 53.8. Conclusion: The 5-yearresults of the study show clinically acceptable values of mean bone loss after 5 years of loading. Implant-supported removable prostheses seem to be a strong co-factor for extensive bone level changes compared to fixed reconstructions. However, these results have to be considered for evaluation of the included special cohort under private dental office conditions. Keywords: dental implant, peri-implant bone loss, platform switching, radiographic analysis, risk factor analysis

The aim of this article is to report a case of necrotizing sialometaplasia with long-term follow-up. A case of necrotizing sialometaplasia in a 37-year-old man with clinical documentation on the progress during a 2-year follow-up is presented. Data from an extensive review of the literature including clinical, imagenologic, and microscopic features are provided. Information on diagnostic and prognostic factors is offered and comprehensibly discussed. The importance of identification and diagnosis of this entity during the review of the slides from the first biopsy is stressed and the exclusive performance of an incisional biopsy is debated. The presented clinical photographs reveal the clinical changes of the lesion from the beginning of the lesions up to 2 years follow-up, documenting the complete long-term clinical course and the healing process of this entity. Keywords: necrotizing sialometaplasia, oral squamous cell carcinoma, salivary gland lesions, salivary glands

Objective: The aim of this report is to describe symptoms that can suggest the presence of a patent nasopalatine duct and to illustrate three cases. Summary: Patent nasopalatine ducts connecting the oral cavity with the nasal cavity are extremely rare. This malformation can be considered a developmental abnormality. Clinically, patent nasopalatine ducts appear as single or double spherical or oval apertures lateral or posterior to the incisive papilla. This type of anatomical malformation can be associated with an unclear pain sensation in the anterior maxillary region, which may be misinterpreted for example as toothache of endodontic origin. However, persisting nasopalatine ducts can also exist as an asymptomatic abnormality with no clinical sign of discomfort. Accordingly, understanding the differential diagnosis of a possible patent nasopalatine duct can prevent a general practitioner from performing unnecessary interventions, such as endodontic treatments, apical surgeries, or tooth extractions. Keywords: incisive papilla, misdiagnosis, nasopalatine duct, vomeronasal organ

Objectives: A variety of theories on the pathogenesis of temporomandibular disorders (TMD) exists resulting in treatment approaches ranging from the fabrication of occlusal splints to alternative treatment modalities such as osteopathy. The goal of this pilot study was to investigate whether osteopathic treatment causes spatial changes in the maxilla. Method and Materials: Following ethics commission approval and informed patient consent, three patients diagnosed with TMD participated in this investigation. In addition to regular treatment, an individualized mandibular occlusal splint was fabricated and a maxillary silicone impression was made. Following osteopathic treatment, the splint was adapted intraorally and another maxillary impression was made. Before and after treatment, the splint and the impressions were scanned three-dimensionally. The resulting images were superimposed using best-fit matching algorithms. Results: Inconsistent spatial changes in the posterior areas were observed both in the maxillary impressions as well as in the mandibular splints reaching maximum absolute values of 0.50 mm. Conclusion: Based on this pilot study, it appears that osteopathic treatment may be capable of inducing spatial changes in the maxilla due to sutural movement thereby validating the fundamental principles of osteopathic treatment. Although, based on the study conducted, it cannot be concluded that osteopathy constitutes a successful treatment alternative in TMD patients, practitioners should be aware of this treatment modality. Keywords: dental splint, osteopathy, sutural movement, temporomandibular disorder