Quintessence International, 03/2019

In many areas of restorative dentistry, metal-free materials offer an alternative to metal-based restorations while ensuring high levels of biocompatibility and esthetics. Rapidly evolving CAD/CAM technology has significantly expanded the range of materials available, providing access to materials classes and their combinations not previously available within conventional manufacturing, such as zirconia ceramics and hybrid ceramics. In addition, digital methods offer previously unavailable options in diagnostics, greater planning reliability, better material quality through standardization of the manufacturing process, and reproducibility - significant benefits that can be used to advantage, especially in oral implantology. Even though technological progress in the field of metal-free materials has given rise to considerable improvements in their mechanical properties over the decades, their clinical long-term success is still very much dependent on an appropriate indication and proper material selection, on the knowledge and skills of the dental practitioner and dental technician, and on an adequate occlusion concept. The high rate of innovation - both with regard to the materials themselves and to CAD/CAM technology - therefore requires an adequate level of prior knowledge to sensibly and successfully implement the wide range of possibilities now open. It is becoming more and more puzzling for users to find their way around the many different new techniques and materials. This review article provides an up-to-date overview of the possibilities and limitations of metal-free implant-supported single-tooth restorations. This first part discusses abutments and cemented crowns. Resultant treatment concepts are presented and evaluated based on clinical examples. Schlagwörter: abutments, CAD/CAM, hybrid abutments, implant prosthetics, implant-supported crowns, lithium disilicate, lithium silicate, monolithic restorations, polymers, titanium adhesive bases, zirconia, zirconium oxide

Objectives: This systematic review aims to discuss the shaping properties and outcomes of nickel-titanium (NiTi) rotary and reciprocation systems assessed by micro-computed tomography. Data source: A literature search was conducted in PubMed and SCOPUS database until April 2018 to identify investigations examining the shaping properties and outcomes of rotary and reciprocation NiTi systems using micro-computed tomography. In addition, a quality assessment was undertaken for the included studies. Results: A total of 1,110 titles were identified in the literature search. After removal of duplicates, 25 studies satisfied the inclusion criteria. Quality assessment showed that 17 studies were of low risk of bias. Six shaping properties and outcomes including centering ability, transportation, untouched canal walls, canal surface area and volume, microcrack formation, and debris accumulation were discussed. Conclusions: The use of the same system in rotary or reciprocation motions and reciprocating single file systems have comparable transportation and centering ability. No difference was observed between rotary and reciprocation systems/motions in surface area and volume of the canal changes. Untouched canal walls and accumulation of debris remained controversial. No relationship was found between kinematics of instrumentation and the formation of dentinal cracks. Schlagwörter: micro-computed tomography, nickel-titanium, reciprocation, rotary, shaping properties

Objectives: To investigate the novel use of computer-aided dynamic navigation for guided endodontics. Method and materials: Dental casts were fabricated from sets of extracted human teeth. A cone beam computed tomography (CBCT) scan of each cast, with a molded thermoplastic stent and a radiographic marker attached, was obtained and imported into the planning software of a dynamic navigation implant surgery system. Simulating implant surgery but for guided endodontics, the drilling entry point, angle, pathway, and depth of virtual implants were planned for 29 selected teeth. The radiographic marker was replaced with a jaw tag and mounted in a phantom head. A drill tag was attached to the drill handpiece. Following calibration, guided by the stereoscopic motion-tracking camera via the tags and images on a computer monitor providing real-time dynamic plus visual intraoperative feedback, the handpiece was aligned accordingly and endodontic access cavity preparation carried out. Successful root canal location was confirmed using periapical radiographs and CBCT. Results: Conservative access cavities were achieved and all the expected canals were successfully located in 26 teeth (n = 29). Due to tracking difficulties, only one canal was located in two maxillary second molars; in a maxillary first molar, only two canals were located and the access preparation for the third canal was misaligned and off-target. Conclusions: The results of this study demonstrate the potential of using computer-aided dynamic navigation technology in guided endodontics in clinical practice. Schlagwörter: access cavity, cone beam computed tomography, dynamic navigation, endodontics, guided endodontics

Objective: Considerable emphasis has been placed on the fear that patients undergoing oral surgery have of the local anesthetic injection. However, other potential factors such as fear of pain during the operation, fear of the operation itself, and fear of postoperative pain are often not considered. The purpose of this study was to determine how patients rank their fear of these four factors. Such information can be helpful in improving patient management. Method and materials: Patients 18 years of age and older presenting to the Oral Surgery Clinic of the Virginia Commonwealth University School of Dentistry for tooth extraction were asked to complete a brief questionnaire ranking their fear of the four previously noted factors, as well as to include their age, gender, and level of education. Results: One hundred patients (52 females and 48 males), ranging in age from 18 to 93 years, completed the survey. Sixty-one had a high school education, 22 had some college education, and 17 had a college degree or higher. Twenty-five ranked pain from the local anesthetic as their greatest fear, 26 ranked pain during the operation as their greatest fear, 18 ranked the operation as their greatest fear, and 31 ranked fear of postoperative pain the highest. There were some significant differences in the rankings between females and males. Conclusions: The results of this study show that patients have fear of pain during and after the procedure as well as of the local anesthetic injection. To maximize patient comfort, how all these factors will be properly managed needs to be discussed preoperatively. Schlagwörter: anesthesia, fear, gender, oral surgery, pain

Acute myeloid leukemia is a bone marrow malignancy in which blasts count increases by more than 20% in the bone marrow. Allogeneic hematopoietic stem cell transplantation (alloHCT) is a treatment option for these patients with high risk of graft versus host disease (GVHD) development. Chronic GVHD (cGVHD) often mimics a variety of autoimmune conditions such as systemic lupus erythematous or systemic sclerosis. Sclerotic cGVHD has a wide spectrum of oral manifestations, including mucosal atrophy, microstomia, and hyposalivation. This report presents a full-mouth implant-retained reconstruction in a 35-year-old male patient who had undergone alloHCT for treatment of acute myeloid leukemia and developed sclerotic cGVHD afterwards. Implant-retained prosthetics might be a practicable treatment for patients with these complications. Schlagwörter: dental implants, graft versus host disease, hematopoietic stem cell transplantation, microstomia, xerostomia

Objectives: Chronic kidney disease (CKD) is a public health problem worldwide. Currently, the link between oral health status, dialysis modality, and dialysis vintage is still not clear. The aim of this study was to evaluate periodontal disease, dental caries, and Candida colonization among patients under hemodialysis (HD) therapy, peritoneal dialysis (PD) therapy, and PD with previous history of HD (HD/PD). Method and materials: The clinical history, smoking, and oral hygiene habits were recorded. Decayed, missing, or filled teeth (DMFT) index, Visible Plaque Index (VPI), clinical attachment level (CAL), bleeding on probing, saliva flow rate, saliva pH, and oral yeast colonization were assessed. Results: HD/PD patients were generally submitted to longer periods of dialysis therapy than the other groups. The number of decayed and filled teeth did not differ between groups; HD patients presented a higher number of teeth, but poor periodontal status. Among the three groups, HD patients presented higher VPI, CAL, and oral Candida colonization, independently of the time under dialysis therapy. Candida albicans (HD and PD), Candida krusei (HD), and Candida carpophila (PD) were isolated in these patients. Conclusion: HD presented a more adverse impact on oral health than PD, particularly periodontal disease and oral Candida colonization; however, this impact on oral health appears to be reduced or ameliorated when patients change from HD to PD therapy. Schlagwörter: Candida, oral health, periodontal disease, renal insufficiency, renal replacement therapy, saliva

Objective: This aim of this study was to determine the prevalence and branching patterns of the inferior alveolar canal (IAC) in premolar and molar areas using cone beam computed tomography (CBCT). Method and materials: CBCT volumes from partially or fully edentulous premolar and molar areas were investigated retrospectively. The presence of such branches with their patterns, sides, and areas, as well as the sex of the patient, were recorded by two observers and analyzed statistically. The branching patterns were initially classified into three types: A, superior type; B, forward type; and C, plexus type. During the investigation, an additional type was found in the premolar area and was classified as type D, an anterior extension type. Results: In total, 243 mandibular sites in 176 subjects were included. Among them, 106 sites displayed branches (43.62%). In the premolar area, most branches were of the anterior extension type (D, 33%), followed by the superior and plexus types (A and C, respectively, 29%), and the forward type (B, 9%). In the molar area, the plexus type was the most common finding (C, 39%), followed by the superior type (A, 32%) and the forward type (B, 29%). Branches in the molar area were significantly more frequent in men than in women (P = .011). Conclusion: IAC branches with four branching patterns in the premolar and molar areas are not rare and could be detected by CBCT. Clinicians should be aware of these branches during surgical procedures concerning the posterior mandible. Schlagwörter: bifid mandibular canal, branching pattern of inferior alveolar canal, cone beam CT, inferior alveolar canal, trifid mandibular canal

Objectives: The effect of gingival retraction paste versus gingival retraction cord on periodontal tissue health is controversial. The aim of the present study was to evaluate the effect of gingival retraction paste versus gingival retraction cord on periodontal health by a systematic review and meta-analysis and to provide scientific guidelines for gingival retraction method selection in clinical work. Data Sources: The databases were systematically queried to collect studies exploring the effect of gingival retraction methods on periodontal tissue health in randomized controlled trials. Literature covering the period of January 1998 to April 2017 was extracted and the quality was assessed, followed by a random-effects meta-analysis with standardized mean differences and 95% confidence intervals. Eight studies met the inclusion criteria. The result of meta-analysis revealed that gingival retraction paste exhibited a less deleterious effect on the periodontal tissue compared with the gingival retraction cord technique measured by probing depth, Gingival Bleeding Index, and bleeding on probing (P .05). However, no statistically significant differences were found in the measurements of Plaque Index, Gingival Index, and gingival recession between these two methods (P > .05). Conclusions: Gingival retraction paste can work better than the gingival retraction cord method in protecting periodontal tissue health. Schlagwörter: gingival retraction cord, gingival retraction paste, meta-analysis, periodontal health, systematic review

Objective: The purpose of this study was to determine whether the persistent high-frequency noise produced by dental equipment could cause hearing impairment among the dental professionals in the United Arab Emirates (UAE). Method and materials: This cross-sectional study was conducted to evaluate the hearing capacity of 90 randomly selected dental practitioners from different specialties working in the UAE. The participants were approached in their workplace and their hearing capacity was evaluated using the pure tone audiometer. Results: Twenty dental practitioners suffered from hearing impairment, which constitutes 22.2% of the studied sample. At high frequencies, left ears were more affected than right ears, but this was not statistically significant. There was a direct relationship between working hours per week and the hearing capacity, but this did not reach a statistically significant level. The lowest hearing capacity was detected in males at a significantly lower value compared to females. Conclusions: Positive correlation was found between years of experience and reduced hearing capacity among dental practitioners. In addition, males had a significantly higher median count of severely affected hearing frequencies compared to females. Online pure tone audiometric testing is an easy, cost-effective tool that can be used to self-assess the hearing capacity of dental professionals, and it is recommended to perform this test annually. Schlagwörter: audiometer, dentist, hearing loss, noise-induced