Quintessence International, 08/2017

Objective: This retrospective study evaluated the clinical success and survival of monolithic lithium disilicate single crowns in the posterior region fabricated with feather-edge margins and cemented with resin-based self-etching cement. Method and Materials: In total, 627 pressed monolithic lithium disilicate restorations on posterior teeth (110 first premolars, 151 second premolars, 240 first molars, 121 second molars, 5 third molars) were placed in 335 patients. All teeth were prepared with feather-edge margins and restored with single crowns. The modified California Dental Association criteria were used to clinically evaluate subjects during regular maintenance recalls. Results: The mean follow-up time was 48.17 months (SD, 27.7; range, 6 to 144). Nine crowns were replaced during the follow-up period due to bulk fracture of the material (overall 97.93% survival rate), and four teeth were extracted. No other technical or biologic failure was observed. Conclusion: In this retrospective evaluation, monolithic lithium disilicate crowns with feather-edge margins yielded clinical outcomes similar to those reported with other margin designs and materials. Following the same clinical protocol, crowns on second molars showed lower survival rates when compared to restorations on other teeth in the posterior region. Careful evaluation is mandatory in high-risk patients and terminal teeth. Alternative restorative materials, such as full-contour zirconia crowns, should be considered for the restoration of second molars. Keywords: feather-edge, knife-edge, lithium disilicate, minimally invasive preparations, posterior single crowns

Objective: Spacers are commonly placed between the canal orifice and the temporary material between endodontic treatment appointments. This prevents the temporary restoration material from obstructing the canal orifices and allows for easy removal. Various endodontic spacers are currently used, including polytetrafluoroethylene (PTFE) tape. Previous in-vitro studies have demonstrated the advantages of using PTFE over using cotton; however, no in-vivo studies have demonstrated this. Hence, the purpose of this study was to evaluate which spacer showed less bacterial leakage between endodontic treatments. Method and Materials: Fifty patients participated in the study and were randomly assigned to either the cotton or the PTFE group. Root canal treatments were completed in two appointments. Cotton and PTFE spacers were collected after a 2- to 4- week time interval between the first and second appointments. Samples were incubated on agar plates for 48 hours and then evaluated for presence of microbial growth. Colony forming units (CFUs) were counted for each of the samples. The results were analyzed using nonparametric statistical tests. Results: Fifteen of the 24 cotton spacers and two of the 24 PTFE spacers were positive for bacterial growth. Conclusion: Cotton fibers exposed to the oral environment could potentially wick contaminants into the pulp chamber. The tendency of cotton to distort under masticatory forces may allow disruption of the temporary material's marginal seal. Based on the results of this study, the use of PTFE is strongly recommended over cotton as an endodontic spacer material. PTFE performed better than cotton in this in-vivo microbial study. Keywords: cotton, endodontic spacers, PTFE, root canal therapy

Objective: The masticatory function of implant-retained overdentures with different attachments has not been sufficiently investigated. This study evaluated the masticatory function of implant-retained mandibular overdentures with ball and resilient telescopic attachments. Method and Materials: Twelve edentulous participants were rehabilitated with new maxillary and mandibular conventional dentures (CD). Three months later, two implants were installed in the canine regions of the mandible. Following a 3-month healing period, duplicate overdentures were constructed for all patients. In a simple random method, six participants were first given ball-retained overdentures (BOD) and the other six received resilient telescopic-retained overdentures (TOD). After testing these prostheses, the first group received the TOD, while the second group received the BOD. Masticatory functions (chewing efficiency [unmixed fraction, UF] and electromyographic activity [EMG] of masseter muscles) were measured 3 months after wearing each of the following dentures: CD, BOD, and TOD. UF was measured using chewing gum and EMG was recorded for right and left bellies of masseter muscle during clenching with (soft and tough) and without foods. Results: Regardless of attachment type, implant-retained overdentures demonstrated significant decrease in UF and significant increase in EMG compared to CD. TOD recorded significantly lower UF and significantly higher EMG when compared to BOD. Conclusion: The TOD improves masticatory functions when compared to BOD. Such improvement may be related to the increased retention and stability of these dentures. Keywords: chewing efficiency, EMG activity, implant, overdenture, telescopic attachments

Patients with an Angle Class III malocclusion are generally treated by orthodontics with or without orthognathic surgery. A literature search revealed very few articles describing solely the prosthodontic treatment of a Class III malocclusion, as it is rarely used as a treatment modality in these cases. The purpose of this article is to show the effects and benefits of an increase in the vertical dimension of the occlusion (VDO) in patients with a Class III malocclusion. An increase in the VDO causes a clockwise rotation of the mandible, thereby increasing the reverse overjet. This phenomenon allows a prosthodontic treatment of the Class III malocclusion in some patients. Therefore, proper diagnostic procedures, careful planning, and a simulation of the final appearance by wax-up and mock-up are mandatory when choosing the modality of prosthodontic treatment. A case with a Class III malocclusion, treated solely by prosthodontic means, is presented. The implemented prosthodontic treatment included the correction of the crossbite and the occlusal plane, the reestablishment of the anterior and canine guidance as well as the provision of a stable occlusion and enhanced facial and dental esthetics. It is proposed that an increase of the VDO should be taken into consideration whenever a patient with a Class III malocclusion is prosthodontically treated. Keywords: case report, Class III malocclusion, increase of vertical dimension of the occlusion (VDO), fixed prosthodontic treatment

Objective: To explore the long-term in-vivo effect of different dental restorative materials on the surrounding enamel and dentin, in primary molars. Method and Materials: Sixteen naturally exfoliated primary molars restored with amalgam, compomer, and glass-ionomer cement were collected after 2 to 5 years of function in the mouth. Four intact molars served as control. The teeth were sliced buccolingually and the ion content in the restorative material, the enamel, and the dentin surrounding the restoration was determined using a scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) program. Results: Amalgam released copper to the enamel and dentin causing a bluish discoloration. No traces of mercury or other ions were detected in the enamel or dentin. The enamel and dentin surrounding the restoration showed reduced inorganic components and increased organic components. The enamel and dentin surrounding the compomer restoration showed similar to amalgam reduction in inorganic components and increased organic components. Traces of fluoride, aluminum, and silicon were found. The enamel and dentin of teeth restored with glass-ionomer cement showed the least reduction in inorganic components, with higher fluoride content and traces of aluminum, silicon, and strontium. Conclusion: This long-term in-vivo study showed release of copper ions from amalgam material to the enamel and dentin, but no traces of mercury. Amalgam and compomers showed no remineralization effect on the dentin surrounding the restoration. Glass-ionomer restorations showed remineralization effect on the tooth components and migration of inorganic ions from the enamel and dentin to the material. Keywords: amalgam, compomer, dentin, enamel, glass-ionomer, primary molars

Objective: In this review article, the role of the dentist in the evaluation and treatment of snoring and Obstructive Sleep Apnea Syndrome (OSAS) in children is described. Snoring and OSAS in children is receiving increased awareness, with reported rates approximating 10% of children who regularly snore, and up to 4% who suffer from OSAS. OSAS in children may have serious developmental and behavioral consequences. Apnea Hypopnea Index (AHI) is the main outcome of the polysomnography test, but its diagnostic values differ from children to adults, as do treatment approaches. Data Sources and Study Selection: A comprehensive literature search of publications from 1973 to 2017 in the PubMed Direct databases was performed to collect information about snoring and OSAS in children. The search was limited to peer-reviewed articles written in English with a few exceptions in other languages. Conclusion: Dentists play a significant role in early detection of OSAS, helping in reducing and preventing its serious consequences. A multidisciplinary treatment team, which manages and treats OSAS, should include the dentist in addition to the sleep specialist and the ENT physician. Keywords: adenoidectomy, obstructive sleep apnea, pediatric, sleep-disordered breathing, snoring, tonsillectomy

In contemporary reconstructive periodontal and implant surgery, attaining uncomplicated wound healing in the early postoperative healing phase is the key to achieving a successful treatment outcome and is of central interest, from the clinical as well as the scientific perspective. The realization of primary wound healing is the central challenge in most cases. Two of the evidence-based factors that affect postoperative wound healing can be influenced by the surgeon: the blood supply to the surgical site and postoperative wound stability. The surgical suture is a key determinant of whether adequate wound stability is achieved in this context without complicating the course of wound healing by exerting unnecessary trauma or excessive tensile strain on the wound edges. Therefore, the inclusion of anchors in the suturing process that make it possible to achieve the best wound stability possible is often an important key to success. This article provides an overview of the principles of successful wound closure that are relevant to postoperative wound healing in order to equip dentists with the tools needed for the correct, indication-specific selection and performance of surgical suturing techniques in daily practice. (Quintessence Int 2017;48:647-660; originally published (in German) in Implantologie 2016;24:281-294; doi: 10.3290/j.qi.a38706) Keywords: microsurgery, suture anchoring, suture material, suturing technique, wound closure, wound healing

Objective: The aim of this study was to assess and present, using sialo-cone beam computed tomography (sialo-CBCT) examination, cases of submandibular gland (SM) chronic obstructive sialadenitis (COS) caused by dental rehabilitation. Data Sources: Clinical and radiographic data of all patients referred for SM sialo-CBCT imaging in the Oral and Maxillofacial Imaging Unit with recurrent SM swelling between January 2012 and July 2015 were reviewed. Cases with suggested iatrogenic cause were selected and described. A literature review of similar cases was also performed. Results: Seventy-one patients with salivary gland (SG) swelling were referred for SM sialo-CBCT. Of these, 16 had implant-supported fixed partial prostheses and seven had full mandibular overdentures. In five patients, COS was diagnosed and a causal relationship between their dental rehabilitation and symptoms was suggested. A literature search revealed 11 cases of SM COS secondary to anterior mandibular rehabilitation. Conclusion: Clinicians rehabilitating the anterior edentulous mandibular region should be aware that both fixed and removable devices may block the orifices of the SM, causing COS.

Objective: The purpose of this study was to evaluate the accuracy of full-arch scans using 11 different cast scanners. Method and Materials: Dental arch length (AL), intermolar width (IMW), and intercanine width (ICW) of the reference plaster casts were measured using a coordinate measuring machine (Zeiss O-Inspect 422). The master cast was subsequently scanned 37 times using 11 desktop scanners (3Shape R500, 3Shape R700, 3Shape R1000, 3Shape R2000, Medianetx grande, Medianetx colori, DentaCore CS ULTRA, Dentaurum OrthoX, Maestro 3D, Imetric IScan D104i, GC Aadva Lab Scan). Using the software Convince Premium 2012 (3Shape), AL, IMW, and ICW were measured on the digital models and compared to the reference plaster cast. Results: The accuracy of the cast scanners differed significantly. The most accurate measurements were given by the cast scanners 3Shape R700 (ICW: 7.4 ± 5.9 µm) and Imetric IScan D104i (ICW: 9.1 ± 4.9 µm). The cast scanners 3Shape R1000 (ICW: 11.2 ± 3.4 µm) and GC Aadva Lab Scan (ICW: 13.8 ± 8.1 µm) yielded comparable measurements. DentaCore (ICW: 26.6 ± 7.5 µm) and Dentaurum OrthoX (ICW: 31.1 ± 24 µm) were significantly less accurate. Conclusion: Almost all scanners demonstrated a level of accuracy so high that further improvement would not provide additional benefit for use in orthodontics. Advancement of the scanners should focus primarily on reducing time and cost. For prosthodontic use, the scanners with the highest accuracy are recommended. Keywords: accuracy, CAD/CAM, desktop scanner, digital model, full-arch scan, plaster cast