Peter A. Reichart’s research while affiliated with Charité Universitätsmedizin Berlin and other places

Background: Total stability of dental implant can be obtained from resonance frequency analysis (RFA) device, but without primary and secondary stability values. Purpose: To formulate mathematical equations for dental implant stability patterns during the osseointegration period. Materials and methods: An online systematically search of the literature between January 1996 and December 2017 was performed for all prospective clinical trials that measured implant stability using RFA device during the osseointegration period. Initial mathematical function with adjustable parameters were created. Then curve-fitting was performed using a computerized program to formulate mathematical equations stability patterns. Results: Nine publications (24 study groups) were included in the mathematical analysis. Curve fitting with low sum of squared errors could be applied in all studies, except one. The stability has been divided into high, medium, and low stability. The curve fitting showed stability dip areas and intersection point which predict the returning of the stability to reach the primary stability. The study groups with low primary stability showed the poorest results, the high and medium stability group showed the stability pattern following the assumed primary stability pattern according to the mathematic equations. Conclusions: The model of primary and secondary stability could be predicted from the proposed equations.

Background: To give an overview on implant survival rates in patients with oral manifestations of systemic autoimmune (oral Lichen planus (oLp), Pemphigus (Pe)), muco-cutaneous (Epidermolysis bullosa (EB)), autoimmune multisystemic rheumatic diseases (Sjögren's syndrome (SjS), systemic Lupus erythematosus (sLE), or systemic Sclerosis (sSc)). Material and methods: Systematic literature review (PubMed/Medline, Embase) using MESH and search term combinations, published between 1980 and August 2018 in English language reporting on dental implant-prosthetic rehabilitation of patients with oLp, Pe, EB, SjS, sLE, sSc, study design, age, gender, follow-up period (≥ 12 months), implant survival rate. Implant-related weighed mean values of implant survival rate (wmSR) were calculated. Results: After a mean follow-up period (mfp) of 44.6 months, a wmSR of 98.3 % was calculated from data published for patients with oLp (100 patients with 302 implants). Data of 27 patients (152 implants) with EB revealed wmSR of 98.7 % following mfp of 32.6 months. For 71 patients (272 implants) with SjS, wmSR was 94.2 % following a mfp of 45.2 months, and for 6 patients (44 implants) with sSc, wmSR was 97.7 % after mfp of 37.5 months. One case report on one patient each with Pe (two implants) as well as sLE (6 implants) showed 100 % SR following at least 24 months. Conclusions: Guidelines regarding implant treatment of patients with oLp, Pe, EB, SjS, sLE or sSc do not exist nor are contraindicating conditions defined. Implant survival rates of patients affected are comparable to those of healthy patients. For implant-prosthetic rehabilitation of patients with Pe and sLE no conclusions can be drawn due to lack of sufficient clinical data. Implant-prosthetic treatment guidelines regarding healthy patients should be strictly followed, but frequent recall is recommended in patients affected with oLp, SjS, EB, SSc, Pe or sLE.

This study evaluated the accuracy of cone beam computed tomography (CBCT) measurements using post-surgical, implant placement, CBCT images by measuring the length and width of implants on CBCT images and comparing these measurements to the actual sizes of the implants, as well as investigated critical anatomical structure injuries after using CBCT for planning. Ninety-six post-operative CBCT scans of 171 dental implants, placed between October 2012 and March 2015, were included in the study. Each implant was measured on the CBCT images for both diameter and length, using the measuring tool in the CBCT software. The measured values were compared with the actual implant diameters and lengths and calculated as a percentage of error. The mean percentage of error was 2.26%. There were no significant differences in percentage of error between implant size, implant diameters, implant positions, upper jaw, lower jaw, anterior area, or posterior area (p>0.05). Anatomical structure injuries were not found post-operatively. The accuracy of CBCT used for measurement in this study was 97.74%, and comparable to that reported for other commercial CBCT machines. The use of CBCT for implant planning can avoid anatomical structure injuries.

Purpose: The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. Methods: The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer's recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Results: Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). Conclusions: Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading.

Objectives The purposes of this study were to examine the correlation between the stability of dental implants and bone formation markers during the healing period and to monitor the stability of dental implants using the resonance frequency analysis (RFA) method. The null hypothesis of the study is no correlation between the stability of dental implant and bone formation markers. Methods The study is a prospective clinical study during the 3-month healing period of implant. At implant placement (PW Plus, Nakhon Pathom, Thailand) and after 1, 2, 3, 4, 6, 8, 10, and 12 weeks, RFA assessments were performed and gingival (GCF)/peri-implant crevicular fluids (PICF) were collected from ten patients. The level of osteocalcin (OC) was measured by using ELISA kits, and the level of alkaline phosphatase (ALP) activity was measured by colorimetric analysis. Repeated measures analysis of variance, the Friedman test, the Mann-Whitney U test, and the Pearson correlation were performed for data analysis. ResultsThere was a statistical decrease in the mean implant stability quotient (ISQ) values between 1 and 3 weeks (P < 0.05). The ISQ values recovered to the initial values at 4 weeks. There was no statistical difference in the ALP level at each measurement, while there was a statistical increase in the OC level at 6, 8, 10, and 12 weeks when compared with 1 week (P < 0.05). There was a significant correlation between ALP levels and ISQ values (r = 0.226, P < 0.05). There was a statistically significant correlation between OC levels and ISQ values at 1–12 weeks (r = 0.245, P < 0.05). Conclusions The ISQ values were weakly correlated with both ALP and OC. The three-thread-design implant showed a high stability through healing period.

Background: Dental implant-retained overdentures have been chosen as the treatment of choice for complete mandibular removable dentures. Dental implants, such as mini dental implants, and components for retaining overdentures, are commercially available. However, comparative clinical studies comparing mini dental implants and conventional dental implants using different attachment for implant-retained overdentures have not been well documented. Purpose: To compare the clinical outcomes of using two mini dental implants with Equator(®) attachments, four mini dental implants with Equator attachments, or two conventional dental implants with ball attachments, by means of a randomized clinical trial. Materials and methods: Sixty patients received implant-retained mandibular overdentures in the interforaminal region. The patients were divided into three groups. In Groups 1 and 2, two and four mini dental implants, respectively, were placed and immediately loaded by overdentures, using Equator(®) attachments. In Group 3, conventional implants were placed. After osseointegration, the implants were loaded by overdentures, using ball attachments. The study distribution was randomized and double-blinded. Outcome measures included changes in radiological peri-implant bone level from surgery to 12 months postinsertion, prosthodontic complications and patient satisfaction. Results: The cumulative survival rate in the three clinical groups after one year was 100%. There was no significant difference (p < 0.05) in clinical results regarding the number (two or four) of mini dental implants with Equator attachments. However, there was a significant difference in marginal bone loss and patient satisfaction between those receiving mini dental implants with Equator attachments and conventional dental implants with ball attachments. The marginal bone resorption in Group 3 was significantly higher than in Groups 1 and 2 (p < 0.05); there were no significant differences between Groups 1 and 2. There was no significant difference in patient satisfaction between Groups 1 and 2 but it was significantly higher than that in Group3 (p < 0.05). Conclusions: Two and four mini dental implants can be immediately used successfully for retaining lower complete dentures, as shown after a 1-year follow up.

The present study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast-associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki-67, Bcl-2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c-met, DNA methyltransferase, podoplanin, TGF-βI, Smad-2/3, Smad-I-5/-8, Smad 4, beta- catenin, calretinin and clonality. Careful interpretation of the findings indicate that the AOT may be more of a hamartomatous than neoplastic nature. This article is protected by copyright. All rights reserved.

The aim of this update was to present the recent notable progress within remaining questions relating to the adenomatoid odontogenic tumour (AOT). Selected issues that were studied included the following: (i) AOT history and terminology, (ii) the so-called peripheral AOT, (iii) AOT and the gubernaculum dentis and (iv) the so-called adenomatoid odontogenic cyst (AOC). The earliest irrefutable European case of AOT was described in 1915 by Harbitz as ‘cystic adamantoma’. Recently, Ide et al. have traced two Japanese cases with irrefutable proof described by Nakayama in 1903. The so-called peripheral (gingival) variant of AOT seems to cover a dual pathogenesis, both an ‘erupted intraosseous’ and an ‘extraosseous’ (gingival) one. In 1992, we theorized that the generally unnoticed gubernaculum dentis (cord and canal) seems to be involved in the development of AOT. Ide et al. have concluded that the dental lamina in the gubernacular cord seems to be an embryonic source of the vast majority of AOTs. The suggestion by Marx and Stern to change the nomenclature of AOT to adenomatoid odontogenic cyst (AOC) is critically discussed. The present authors agree on the background of the work of several groups of researchers and WHO/IARC classifications that the biology of the follicular variant of AOT is already fully explained and does not make room for any change in diagnostic terms. Further, there is no reason to change terminology in this case where improvements or conditions to better clinical management are not an issue.

The 2014–2015 outbreak of the Ebola virus disease (EVD) in West Africa has been considered a major global health emergency by the WHO. Implications for health care providers including oral and maxillo-facial surgeons have been published by the WHO, the Centers for Disease Control and Prevention (USA), and other medical societies and public health organizations. While the risk of infection with the Ebola virus seems to be rather small in Europe, maxillo-facial and plastic surgeons often travel to Africa to treat patients with facial burns, cleft-lip and palate, and noma. The likelihood of an encounter with patients infected by Ebola virus in subsaharan and West Africa, therefore, has increased during the last 2 years. The purpose of this short overview was to summarize the virology of the Ebola virus, transmission, epidemiology, clinical features, oral manifestations, treatment, and possible implications for maxillo-facial surgeons of EDV.