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The term "buccal implant position" is commonly used but lacks a precise definition and missing a reference point. Considering its major impact on peri-implantitis and esthetic failures the purpose of this study was to find a correlation between bucco-palatal implant positioning and the midfacial soft tissue level of implant crowns using newly defined Emergence-points.Patients with unilateral single-tooth implant crowns in the region of the central or lateral maxillary incisor were included in this study. Digital intraoral scans were superimposed over a scan of the master cast or the original digital data set and analyzed in a computer planning program. In relation to the corresponding natural tooth, an ideal Emergence-point (ESeventy-three patients met the inclusion criteria. AD ranged from 0 to 3.5 mm (AD = 0.87 ± 1.01), SIP from 0.2 to 5.1 mm (AD = 2.66 ± 1.64). Statistical analysis showed a significant inverse correlation between AD and SIP (ρ = -.55, p .001). VIP, the implant inclination, time span since implant insertion, and phenotype revealed no significant correlation to AD.The more palatal the implant was positioned, the less AD was observed. The position of the implant shoulder should preferably be planned more than 2 mm behind the ideal E-point. This E-point can be used for implant planning as it defines the ideal crown length for prospective planning. more...

Objectives The aim of the present systematic literature review was to determine whether long-term treatment results with single-tooth implants may differ depending on the timing of implant placement in relation to tooth extraction (immediate IP/early EP/delayed DP) and the timing of prosthetic loading (immediate IL/early EL/delayed DL). Material and methods Electronic and manual searches were performed to identify studies reporting on long-term results (survival rate and/or marginal bone resorption after ≥3 years) of maxillary single-tooth implants in the aesthetic zone using defined placement and loading protocols. Comparative trials were subjected to meta-analyses whilst data from single-arm studies were pooled to evaluate differences between timing protocols. Results A total of 7 controlled trials were considered for meta-analyses: immediate loading was compared to delayed loading in 3 studies on immediate placement (IPIL vs. IPDL, p = .306) and in 2 studies on delayed placement (DPIL vs. DPDL, p = 1.000) whilst 2 studies compared early versus delayed placement with delayed loading (EPDL vs. DPDL, p = .600), however, without significant differences. Pooled data analysis of 29 studies (965 implants) did not show differences between timing of placement or loading as well as marginal bone remodelling. No impact of the one abutment - one time concept, flap design and simultaneous bone or soft tissue augmentation could be established. Conclusions Insufficient data are available for meta-analytic comparison of all combinations of implant placement and loading protocols. more...

Background Due to chronic inflammation or trauma facial bone is frequently missing after tooth loss in the esthetic zone. As a consequence, procedures to augment or at least to preserve bone are frequently necessary prior to implant placement. Purpose The aim of this retrospective case series is to demonstrate the applicability of a staged all-flapless concept to establish satisfactory implant restorations following situations of partial missing facial bone in the esthetic zone. Materials and methods Radiological/clinical data of 25 patients were analyzed and an esthetic evaluation of 24 patients was performed. The staged concept included ridge preservation at time of tooth extraction and delayed guided implant placement. Marginal bone loss was measured radiologically and esthetic evaluation was performed based on standardized photographs using the Pink Esthetic Score as well as the Papilla Index. Results Implant success rate revealed 100%. The mean radiological peri-implant marginal bone loss measured 1.16 mm (SD: 0.16). Regarding the esthetic outcome 71% of patients were evaluated with a Pink Esthetic Score higher or equal to 10 constituting satisfactory esthetics (median pink esthetic score: 10). The mean follow-up time for clinical and radiographic analysis was 1.3 years (SD: 0.6 years) and 1.2 years (SD: 0.6) for esthetic evaluation. Conclusion Although marginal bone loss cannot be avoided, the staged concept of flapless ridge preservation and subsequent delayed flapless guided implant placement carries the potential to improve esthetics of single-tooth implants in the anterior maxilla. more...

Bone grafting of the maxillary sinus is attempted to compensate for sinus pneumatization and permit reliable insertion of endosseous dental implants for prosthetic rehabilitation. The aim of the present clinical investigation was to study bone regeneration four months after transcrestal sinus floor elevation via the Gel-Pressure Technique (GPT) and application of pasteous nano-crystalline hydroxyapatite bone substitute. A total of 25 patients with deficient alveolar ridges in the posterior maxilla (mean residual bone height: 4.7 ± 1.8 mm) were subjected to 32 flapless transcrestal sinus floor augmentations and simultaneous insertion of 40 implants. Sinus membrane elevation height averaged 11.2 ± 2.7 mm and minimal vertical graft resorption of 0.1 mm was observed after four months. Radiographic bone density averaged 460 Hounsfield units in regions adjacent to the native jawbone (1 to 7 mm distance), while reduction of bone density by −7.2%, −11.3%, −14.8%, −19.6% and −22.7% was recorded in more apical regions of 8, 9, 10, 11, and ≥12 mm distance to the original sinus floor, respectively. The results suggest that graft remodeling is completed up to a distance of 7 mm within a healing period of four months after sinus augmentation using nano-crystalline hydroxyapatite bone substitute material. more...

Research on oral surgery and dental implants has a long tradition at the Medical University of Vienna, Austria and is profoundly associated with the head of the Dental Clinic’s Department of Oral Surgery for over three decades, Professor Georg Watzek. He has (co)authored more than 200 scientific papers and edited 9 books in the field. The aim of this series of review articles is to provide an overview of research topics and results published in PubMed listed international scientific journals. The first part presents a summary of publications by Georg Watzek and coworkers in the time period of 1976–1991. Thematic issues involve oral malignancies, neurofibromatosis, macroglossia, amyloidosis, craniosynostosis, maxillary sinusitis, oral anatomy, endoscopic and temporomandibular joint surgery, fibrin adhesives, heavy metal deposits, dental cysts, root resections, interradicular periodontal defects, marginal bone resorption and mucosal condition around dental implants as well as interdisciplinary treatment planning. more...

Periimplantitis is the most frequent cause of late implant failure; however, little is known about the long-term success of periimplantitis treatment and the effectiveness of various therapeutic interventions.A total of 142 patients were referred to the Academy for Oral Implantology in Vienna for the treatment of recurrent periimplantitis around single-tooth implants. Of them, 72 patients (51%) were treated by laser decontamination, 47 patients (33%) by implantoplasty surgery, and 23 patients (16%) by a combination of both approaches.Overall success of periimplantitis therapy was 89% after 9 years of follow-up, and it did not differ significantly between female and male patients (P = 0.426). The number of implant failures that could not be prevented by periimplantitis treatment was 6 after laser decontamination (8%), 6 after implantoplasty surgery (13%), and 4 after a combination of both therapies (17%). Implant loss occurred after 4.9 ± 1.9 years of therapy, on average. No significant difference between the 3 treatment groups could be observed (P = 0.393).The present results suggest that success rates of periimplantitis therapy with either laser decontamination or surgical implantoplasty are high. These success rates do not appear to be associated with patient gender or treatment strategy. more...

Explantation of failed dental implants using a piezoelectric device may provide a viable treatment modality, especially for implants in precarious locations. The traditional mechanical procedures compared to piezosurgical technique for maxillary implant removal are described. Furthermore, the remaining bone on dental implants was analyzed by scanning electron microscopy (SEM) in order to semi-quantitatively evaluate the amount and structure. The piezoelectric device appears to be a valuable minimally invasive alternative if removal of dental implants is required. more...

Aim To gain further insights and resolve conflicting results in the literature regarding prevalence, predominant location and morphologic variability of maxillary sinus septa. Material and Methods Electronic and hand searching of English literature identified 33 investigations published from 1995 to 2011. Septa were defined as at least 2–4 mm in height. Results Septa were present in 28.4% of 8923 sinuses investigated (95% confidence interval: 24.3–32.5%). Prevalence was significantly higher in atrophic sinuses compared with dentate maxillae (p more...

Non-invasive precursor lesions precede the development of oral squamous cell carcinoma. The prevalence of such conditions varies among literature. The awareness of treating dentists enables a timely diagnosis and treatment. A total of 230 patients with oral soft tissue lesions were examined during a 1-year period at the Department of Oral Surgery, Medical University of Vienna. The following data were collected: the type of lesion, benign, potentially malignant and malignant lesions according to gender and different age groups. The most common lesions were fibrous hyperplasia (n = 57; 25%), lichen ruber (n = 46; 20%) and leukoplakia (n = 36; 16%). Precursor lesions were present in 38% (n = 87) and malignoma in 3% (n = 7) of the patients. Most lesions were found in patients between the age of 30 and 60 years (n = 132; 57%). Precursor lesions have a high prevalence in the younger population (30–60 years of age). The referring practitioners act well in collaboration with a specialized center. Teamwork in healthcare promotion is important in the management and prevention of precursor lesions. more...

Pommer B, Frantal S, Willer J, Posch M, Watzek G, Tepper G. Impact of dental implant length on early failure rates: a meta-analysis of observational studies. J Clin Periodontol 2011; 38: 856–863. doi: 10.1111/j.1600-051X.2011.01750.x. Abstract Aim: To test the null hypothesis of no difference in failure rates of short (minimum length: 7 mm) and longer dental implants (10 mm), a meta-analysis was performed on prospective observational trials. Materials and Methods: A systematic electronic and hand search was performed to identify eligible studies. Having additional data supplied by the authors, 54 publications were included (19,083 implants). Results: In case of mandibular implants, the null hypothesis of no impact of reduced implant length on failure within the first year of prosthetic loading could not be rejected. A significant impact of implant length could be substantiated for short machined implants in the anterior [odds ratio (OR) 5.4] and posterior maxilla (OR 3.4), while short rough-surfaced implants demonstrated increased failure rates in the anterior maxillary sites. No influence of implant diameter and denture type on the failure rate of short implants could be revealed. Conclusion: In areas of reduced alveolar bone height the use of short dental implants may reduce the need for invasive bone augmentation procedures. more...

Objectives: Altered pulp sensitivity of anterior lower teeth is a frequent finding following chin bone harvesting. Persistent loss of tooth sensitivity has been reported in up to 20% of the patients. The aim of this study was to evaluate current recommendations for the location of the harvest zone with respect to the course of the mandibular incisive canal (MIC), the intrabony continuation of the mandibular canal mesial to the mental foramen. Material and methods: On computed tomographic (CT) scans of 50 dentate mandibles, the MIC was located and its distance to the root apices, to the labial bony surface, and to the inferior margin of the mandible was assessed. The risk of nerve injury and the percentage of patients suitable for chin bone grafting were calculated. Results: Respecting current recommendations for chin bone grafting, the content of the MIC was endangered in 57% of the CTs. Therefore, new safety margins are suggested: the chin bone should be harvested at least 8mm below the tooth apices with a maximum harvest depth of 4mm. Conclusions: Applying the new safety recommendations and proper patient selection in chin bone harvesting could reduce the risk of altered postoperative tooth sensitivity due to injury of the mandibular incisive nerve. more...

Purpose: To assess the methodologic quality of systematic reviews on the effect of platform switching upon peri-implant marginal bone loss. Materials and Methods: An electronic literature search of several databases was conducted by two reviewers. Articles were considered for quality assessment if they met the following inclusion criterion: systematic reviews that aimed at investigating the effect of platform switching/mismatch on marginal bone levels around dental implants. Two independent examiners evaluated the review publications using two quality-ranking scales (assessment of multiple systematic reviews [AMSTAR] and Glenny checklist). Descriptive statistics were used to summarize the results, and Cohen’s kappa coefficients were calculated to appraise interrater agreement of each checklist. Results: Overall, five systematic reviews (including three of them with meta-analysis) were evaluated. The mean AMSTAR score ± standard deviation was 8.4 ± 2.6 (range, 4 to 11), and the mean Glenny score was 10.8 ± 2.9 (range, 6 to 14), showing high statistical correlation (rs = 0.98, P = .005). Cohen interexaminer test yielded values of κ = 0.88 and κ = 0.86 for the AMSTAR and Glenny checklist, respectively. The AMSTAR items rated positive in 78%, whereas 18% met the criteria for “no” and 4% were “not applicable.” Only one review article met all criteria. Items of the Glenny checklist rated positive in 73% and negative in 27%. All but one study with the lowest quality scores (finding no difference) demonstrated a clinical benefit of implant platform switching in preserving the peri-implant marginal bone loss. Conclusion: According to the quality-ranking scales appraised, substantial methodologic variability was found in systematic assessment of benefits with the platform switching concept to preserve peri-implant bone level. High-quality systematic reviews, however, generally favored platform switching over platform matching. more...

To compare five different implant treatment protocols in the anterior maxilla, including immediate, early, and delayed implant placement, as well as implant placement in conjunction with simultaneous guided bone regeneration and implant placement 3 months following horizontal autologous bone block grafting.Aesthetic indices used included the Pink Esthetic Score (PES), Papilla Index (PI), Subjective Esthetic Score (SES), and White Esthetic Score (WES). Subjective evaluation of implant aesthetics was performed using a visual analogue scale (VAS). The VAS consisted of a 10 cm-long line representing the degree of discontent (0%) or satisfaction (100%).A total of 153 implants in 153 patients (80 women, 73 men) were evaluated after a mean follow-up of 4.5 ± 2.9 years. Mean peri-implant bone loss was 1.6 ± 0.9 mm and not affected by treatment protocol, time after implant placement, or crown length. Papilla presence, by contrast, differed significantly between the protocols: Papilla formation was more pronounced following delayed and immediate implant placement. No statistical significance was found among treatment modalities with regard to PES, SES, or WES. Longer crowns were associated with lower PES and PI ratings and correlated with greater midfacial recession. SES was also influenced by time after implant placement and keratinized mucosa. Patient satisfaction differed significantly among treatment protocols, favoring immediate implant placement. Agreement between objective and subjective aesthetic ratings was low.The present study suggests that comparable clinical, radiological, and aesthetic results can be achieved with all treatment protocols. Gingival recession, however, seems to occur in the long term irrespective of the technique used. more...

To test the null hypothesis of no difference in failure rates of short (minimum length: 7 mm) and longer dental implants (≥ 10 mm), a meta-analysis was performed on prospective observational trials.A systematic electronic and hand search was performed to identify eligible studies. Having additional data supplied by the authors, 54 publications were included (19,083 implants).In case of mandibular implants, the null hypothesis of no impact of reduced implant length on failure within the first year of prosthetic loading could not be rejected. A significant impact of implant length could be substantiated for short machined implants in the anterior [odds ratio (OR) 5.4] and posterior maxilla (OR 3.4), while short rough-surfaced implants demonstrated increased failure rates in the anterior maxillary sites. No influence of implant diameter and denture type on the failure rate of short implants could be revealed.In areas of reduced alveolar bone height the use of short dental implants may reduce the need for invasive bone augmentation procedures. more...

To evaluate a novel surgical technique for flapless transcrestal elevation of the maxillary sinus floor via surgical templates using gel pressure.Computed tomographic scans of fresh human cadaver maxillae and three-dimensional treatment planning software were used to design surgical templates. Access to the maxillary sinus was gained by guided transcrestal osteotomies to puncture the bony sinus floor. By injection of radiopaque gel, the maxillary sinus membrane was elevated to attain a postoperative bone height of 15 mm.The gel-pressure technique was performed in 10 atrophic maxillary sites with a mean residual bone height of the alveolar crest of 4.7 +/- 1.6 mm. The sinus membrane was successfully elevated in all sites without causing iatrogenic perforation (mean elevation height, 10.6 +/- 1.6 mm).The gel-pressure technique may provide a new option for minimally invasive transcrestal sinus surgery and may represent a safe method to increase bone volume in the atrophic posterior maxilla. more...

OBJECTIVES Perforation of the Schneiderian membrane (maxillary sinus mucosa) is a common complication of maxillary sinus graft procedures. Membrane perforation increases the chance of postoperative sinusitis and endangers graft as well as implant survival. The aim of the present study was to explore the mechanical properties of the Schneiderian membrane. MATERIAL AND METHODS Three test methods were performed on sinus specimen of 20 fresh human cadavers: one- and two-dimensional membrane elongation as far as perforation, as well as membrane detachment from the adherent bone. RESULTS Perforation of the Schneiderian membrane (mean thickness: 90 mum) occurred at a mean tension of 7.3 N/mm(2). The membrane could be stretched to 132.6% of its original size in one-dimensional elongation, and to 124.7% in two-dimensional elongation. Thicker membranes demonstrated significantly higher load limits (P more...

At the end of 2012 Professor Georg Watzek retired as head of the Department of Oral Surgery at the Bernhard Gottlieb School of Dentistry, Vienna Medical University. This gives the opportunity to look back on 36 years of publication history since his first research article was published in 1976. Professor Georg Watzek was affiliated to the Department of Oral and Maxillofacial Surgery (Vienna Medical University, Austria, head: Univ. Prof. Dr. Siegfried Wunderer) from 1973 and published his first papers there. After his habilitation in 1980 he became head of the Department of Oral Surgery (University Dental Clinic, Vienna Medical University, Austria) and in 1987 head of the Dental Clinic. From 1983 to 1993 he was editor of the journal Stomatologie, president of the Austrian Society for Oral Surgery and Implantology (1983–2002) and president of the Austrian Dental Association (1989–1993). Professor Georg Watzek is an honorary member of the Hungarian Dental Association (1991) and the German and Czech Society for Implantology (2003). From 1994 to 1997 he was visiting professor at the University of Pennsylvania and in 2003 he served as president of the European Association for Osseointegration (EAO). He is a founding member of the scientific board of the Osteology Foundation in 2004 and became associate editor for the International Journal of Oral & Maxillofacial Implants (JOMI) in 2006. This special issue of The International Journal of Stomatology and Occlusion Medicine gives a survey of all PubMed listed scientific articles published by Watzek and coworkers from 1976 to 2012 structured into four time periods. We hope you enjoy this 36th anniversary compilation of research on oral surgery and implantology in Vienna. J. Stomat. Occ. Med. (2013) 6:1 DOI 10.1007/s12548-013-0085-8 more...