Georg Watzek

Medical University of Vienna, Wien, Vienna, Austria

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Publications (197)464.96 Total impact

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    ABSTRACT: Background Flapless implant placement using surgical templates may guarantee predictable and esthetic results provided that preplanned implant positions are transfered precisely into surgical reality.PurposeThe study aims to investigate the effect of three-dimensional accuracy in guided implant surgery on the esthetic outcome of single-tooth implants in the anterior maxilla.Materials and Methods Single-tooth implants for delayed replacement of upper incisors were inserted in 27 patients using stereolithographic templates. Superimposition of postoperative cone beam computed tomography (CBCT) scans allowed assessment of positional inaccuracy at the implant shoulder and apex, as well as angular deviation. Objective evaluation of implant esthetics was performed after a mean follow-up of 2.3 years using the Pink Esthetic Score (PES).ResultsMean deviation between planned and actual implant position was 0.84 mm at the implant shoulder and significantly correlated to average PES of 12 (p = .031). Inaccuracy toward the buccal side was most frequent (70%). Deviations ≥ 0.8 mm resulted in significantly worse implant esthetics (median PES: 9.5, interquartile range [IQR]: 8–11) compared with more accurate implant positions (median PES: 13, IQR: 12–13, p = .039).Conclusion Positional inaccuracy is low in guided implant surgery, but may however significantly compromise implant esthetics in the anterior maxilla.
    Clinical Implant Dentistry and Related Research 11/2014; · 3.82 Impact Factor
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    ABSTRACT: Rehabilitation of the incomplete dentition by means of osseointegrated dental implants represents a highly predictable and widespread therapy; however, little is known about potential risk factors that may impair long-term implant success.
    Journal of periodontal & implant science 06/2014; 44(3):102-8.
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    ABSTRACT: To clinically and radiographically evaluate dental implant treatment in adolescents with extensive oligodontia. Patients with more than nine permanent teeth congenitally missing and implant treatment before the age of 16 years were included. Clinical follow-ups involved bleeding on probing, plaque index and peri-implant probing value. The peri-implant bone level was analysed on panoramic radiographs at time of implant treatment and at follow-up. Characteristics of the dental implants and patients were retrieved. This study involved 18 patients (nine males, nine females) having 71 dental implants. The lower left premolar was predominantly missing. The mean age at the time of dental implant treatment was 12.5 (±2.6) years. The bleeding on probing value was determined negative on 44%. The mean pocket depth was 3.6 (±1.1) mm. The peri-implant bone level correlated significantly negative with the age at time of implant placement (r = -0.346, P = 0.004). The region of implant habits had no influence on peri-implant bone level. Dental implant treatment in adolescents resulted in a survival rate of 89% (63/71) and a mean loading time of 11.0 (±4.1) years. The implant crowns to be renewed resulted in 54% (9 of 18 patients, 38 of 71 crowns) after a period of 7.8 ± 4.5 years. Dental implant treatment in maturing adolescents with extensive oligodontia before is supported by the data of the present study. Providing that other treatment options are considered, the areas of skeletal growth are respected and the patients are well informed. To enhance quality of life of growing children with oligodontia clinicians are asked to evaluate their long-term outcome on dental implant treatment in adolescents.
    Clinical Oral Implants Research 01/2014; · 3.43 Impact Factor
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    ABSTRACT: Purpose: To evaluate patient satisfaction, oral health-related quality of life, and patients' preferences towards minimally invasive treatment options for graftless rehabilitation of complete edentulism by means of dental implants. Material and methods: A MEDLINE search of literature in the English language up to the year 2013 was performed to summarise current evidence from the patient's perspective. The final selection included 37 studies reporting on minimally invasive implant treatment of 648 edentulous maxillae and 791 edentulous mandibles in 1328 patients, via a total of 5766 implants. Results: Patient satisfaction averaged 91% with flapless implant placement (range: 77 to 100%), 89% with short implants, 87% with narrow-diameter implants (range: 80 to 93%), 90% with a reduced number of implants (range: 77 to 100%), 94% with tilted implant placement (range: 58 to 100%), and 83% with zygomatic fixtures (range: 50 to 97%). Indirect comparison yielded patient preference towards tilted implant placement compared to a reduced number of implants (P = 0.036), as well as to zygomatic implants (P = 0.001). Conclusions: While little evidence on patients' preferences towards minimally invasive treatment alternatives vs. bone augmentation surgery could be identified from within-study comparison, it may be concluded that patient satisfaction with graftless solutions for implant rehabilitation of completely edentulous jaws is generally high. Comparative effectiveness research is needed to substantiate their positive appeal to potential implant patients and possible reduction of the indication span for invasive bone graft surgery. Conflict-of-interest notification: The authors declare that they have no conflict of interest.
    European journal of oral implantology. 01/2014; 7(2):91-109.
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    ABSTRACT: Adhesion of osteogenic cells on titanium surfaces is a prerequisite for osseointegration. Alkali treatment can increase the hydrophilicity of titanium implant surfaces, thereby supporting the adhesion of blood components. However, it is unclear if alkali treatment also supports the adhesion of cells with a fibroblastic morphology to titanium. Here, we have used a titanium alloy (Ti-6AL-4V) processed by alkali treatment to demonstrate the impact of hydrophilicity on the adhesion of primary human gingival fibroblast and bone cells. Also included were the osteosarcoma and fibroblastoma cell lines, MG63 and L929, respectively. Cell adhesion was determined by scanning electron microscopy. We also measured viability, proliferation, and protein synthesis of the adherent cells. Alkali treatment increased the adhesion of gingival fibroblasts, bone cells, and the two cell lines when seeded onto the titanium alloy surface for 1 h. At 3 h, no significant changes in cell adhesion were observed. Cells grown for 1 day on the titanium alloy surfaces processed by alkali treatment behave similarly to untreated controls with regard to viability, proliferation, and protein synthesis. Based on these preliminary In vitro findings, we conclude that alkali treatment can support the early adhesion of cells with fibroblastic characteristics to a titanium alloy surface.
    Clinical Oral Implants Research 12/2013; · 3.43 Impact Factor
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    ABSTRACT: Nitric oxide (NO) is a mediator involved in bone regeneration. We therefore examined the effect of the novel NO donor, S-nitroso human serum albumin (S-NO-HSA) on bone formation in a rabbit calvaria augmentation model. Circular grooves (8mm diameter, two per animal) were created by a trephine drill in the cortical bone of 40 rabbits and titanium caps were placed on the rabbit calvaria bone filled with a collagen sponge soaked with either 100μL S-NO-HSA (5%, 20%) or human albumin (5%, 20%). After 4 weeks the titanium hemispheres were subjected to histological and histomorphometric analysis. Bone formation and the volume of the residual collagen sponge were evaluated. S-NO-HSA treatment groups had a significantly higher volume of newly formed bone underneath the titanium hemispheres compared to the albumin control groups (5%: 15.5±4.0% versus 10.6±2.9%; P<0.05; 20%: 14.0±4.6% versus 6.0±3.8%; P<0.01). The volume of residual collagen sponge was also significantly lower in the S-NO-HSA groups compared to the control groups (5%: 0.4±0.5% versus 2.6±2.4%; P<0.05 and 20%: 1.5±2.7% versus 13.0±18.7%; P<0.01). This study demonstrates for the first time that S-NO-HSA promotes bone formation by slow NO release. Additionally, S-NO-HSA increases collagen sponge degradation.
    International Journal of Oral and Maxillofacial Surgery 10/2013; · 1.52 Impact Factor
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    ABSTRACT: Bone volume available for dental implant placement in the posterior maxilla is frequently reduced by maxillary sinus expansion and resorption of the alveolar ridge following tooth loss. Internal bone augmentation of the sinus floor is routinely performed by elevation of the maxillary sinus membrane via a lateral or transcrestal approach. The key issue in minimally invasive transcrestal techniques is the avoidance of membrane perforation in the course of osteotomy and membrane elevation. Novel devices to reduce the risk of membrane perforation have been recently developed and protected by patents. The present review presents recent sinus membrane elevation techniques (balloon-mediated elevation, hydraulic injection, gel-pressure technique) as well as new approaches to prevent sinus membrane perforation during transcrestal osteotomy (lasers, piezoelectric devices, auto-stop drills). The overview of patented designs is supplemented by an outlook on future surgical techniques and technical possibilities in transcrestal sinus floor augmentation surgery.
    Recent Patents on Biomedical Engineering. 09/2013; 6(3).
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    ABSTRACT: OBJECTIVES: Single-tooth replacement of anterior mandibular teeth is frequently complicated by insufficient bucco-lingual bone width and limited mesio-distal space available for implant placement. The aim of the present study was to assess implant esthetics in the partially edentulous anterior mandible. MATERIAL AND METHODS: Esthetic evaluation of 43 anterior mandibular single-tooth implants in 15 women and 28 men was performed using esthetic indices (PES = Pink Esthetic Score, PI = Papilla Index, SES = Subjective Esthetic Score) as well as subjective patients' Visual Analogue Scale (VAS) ratings. Clinical and radiological parameters (implant and crown dimensions, pocket depth, bleeding on probing, plaque, keratinized mucosa, marginal bone level, and distance to adjacent teeth) were tested for influence. RESULTS: Implant esthetics were judged satisfactory (PES ≤10) in 42% of implants compared with a patient satisfaction rate of 87%. Correlation between objective indices (PES/PI: rs = 0.62, PES/SES: rs = -0.73, PI/SES: rs = -0.48) was highly significant (P ≤ 0.001); however, no association to subjective patients' ratings could be observed. Type of prosthetic restoration (single crown vs. tulip-shaped double crowns), mesio-distal crown width as well as anatomic crown length significantly affected esthetic scores. Patients' judgment, by contrast, could not be associated to any prognostic factor. CONCLUSION: Subjective patient satisfaction with implant esthetics in the partially edentulous anterior mandible is high, however, remains hard to predict or objectively quantify.
    Clinical Oral Implants Research 06/2013; · 3.43 Impact Factor
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    ABSTRACT: BACKGROUND: Intrabony temperature increase is not only dependent on shearing energy and mechanical friction between bone and surgical drill but is also related to heat capacity and thermal conductivity of the surrounding bone and the applied surgical instrument. Thus time of occurrence of the highest temperature rise can be expected after the shearing process of the osteotomy, potentially affecting the process of osseointegration. PURPOSE: The aim of this study was to evaluate temperature changes during the shearing and withdrawing processes during osteotomies. MATERIALS AND METHODS: An overall 160 automated intermittent osteotomies (10/16 mm drilling depth) with 2 mm diameter twist drills and 3.5 mm diameter conical drills and different irrigation methods (without/external/internal/combined) were performed on standardized bone specimens. The drilling cycles were operated by a computer-controlled surgical system, while a linear motion potentiometer and multichannel temperature sensors in various intrabony levels ensured the real-time documentation of temperature changes during the shearing and withdrawing processes. RESULTS: The highest temperature changes were invariably recorded during the process of withdrawal. Significantly lower temperature changes (p < .02) could be recorded at maximum drilling depths during the shearing process regardless of drilling depth, diameter or irrigation method. During coolant supply, 2 mm diameter twist drills showed higher temperatures (10 mm, p < .01/16 mm, p < .03) compared with 3.5 mm diameter conical implant drills. Internal (10 mm, p < .01) or combined irrigation (16 mm, p < .01) was associated with significantly lower temperatures compared with external irrigation by the use of conical implant drills. CONCLUSIONS: Considering that heat generation during osteotomies is a multifactorial scenario, this study could demonstrate that the highest temperature rise during implant osteotomies occurs during the withdrawing process and that the time of occurrence is influenced by predominant factors such as osteotomy depth and mode of irrigation.
    Clinical Implant Dentistry and Related Research 05/2013; · 3.82 Impact Factor
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    ABSTRACT: Platelets modulate formation of osteoclasts and osteoblasts, but research with different preparations of platelets remains inconclusive. Here, we assessed whether serum components modulate the effect of platelet preparations. In murine bone marrow cultures, osteoclastogenesis was investigated in the presence of platelet-released supernatant (PRS), serum containing PRS (SC-PRS), and serum. Osteoclastogenesis was quantified by the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, TRAP activity and resorption assays. Also human osteoclastogenesis assays were performed. Viability and proliferation were tested by MTT and (3) [H]thymidine incorporation assays, respectively. Osteoblastogenesis was assessed by histochemical staining for alkaline phosphatase-of murine bone marrow cultures and human MG63 cells. We found PRS to increase the number of TRAP(+) multinucleated cells in the early phase and TRAP activity in the later phase of osteoclastogenesis. SC-PRS and serum decreased the number and activity of TRAP(+) multinucleated cells. Both serum containing preparations reduced viability and proliferation of hematopoietic progenitors. PRS decreased the numbers of alkaline phosphatase-positive colonies while SC-PRS and serum increased osteoblastmarkers in MG63. Proliferation of MG63 was stimulated by all preparations. These results show that activated platelets support osteoclastogenesis, while platelet preparations that contain serum components decrease osteoclastogenesis and increase osteoblastogenesis in vitro, suggesting that serum components modulate the effects of platelets on osteoclastogenesis and osteoblastogenesis. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
    Journal of Orthopaedic Research 05/2013; · 2.88 Impact Factor
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    ABSTRACT: Peripheral (extraosseous) dentinogenic ghost-cell tumours are extremely rare neoplasms, representing less than 1% of all odontogenic tumours. Only 28 cases (including the present report) are described in literature: the majority of patients (89%) are over 40 years of age (mean: 59.1 ± 20.5 years) and 63% are male. Seventy-three per cent are located in the mandible, and anterior jaw regions are most commonly affected (74%). Erosion of the underlying bone can be observed in 53% radiographically. The present case report describes a recurrent swelling after excisional biopsy of a peripheral dentinogenic ghost-cell tumour in the anterior maxilla of a 78-year-old male patient mimicking tumour recurrence. Histopathological examination of the second biopsy, however, revealed no evidence of ghost-cell tumour recurrence but development of a pyogenic granuloma. In contrast to central dentinogenic ghost-cell tumours, there is no evidence of recurrence of peripheral dentinogenic ghost-cell tumours in literature to date.
    Oral Surgery 05/2013; 6(2).
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    ABSTRACT: OBJECTIVES: Based on a novel standardized bovine specimen, the aim of this study was to investigate thermal effects of different irrigation methods during intermittent and graduated drilling. MATERIAL AND METHODS: Temperature changes during implant osteotomies (n = 320) of 10 and 16 mm drilling depths with various irrigation methods were investigated on manufactured uniform bone samples providing homogenous cortical and cancellous areas and analogous thermal conductivity comparable to human bone. Automated sequences were performed with surgical twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. Real-time recording of temperature increase was done using two custom-built multichannel thermoprobes with 14 temperature sensors at a predefined distance of 1 and 2 mm to the final osteotomy. The effects of drilling depth, drilling diameter and irrigation methods on temperature changes were investigated by a linear mixed model. RESULTS: Using this uniform bone specimen, the greatest temperature rise was observed without any coolant supply with 29.87°C, followed by external with 28.47°C and then internal with 25.86°C and combined irrigation with 25.68°C. Significant differences (P ≤ 0.0156) between drill depths of 10 vs. 16 mm could be observed with all irrigation methods evaluated. With each of the irrigation methods, significantly higher temperature changes (P < 0.0001) during osteotomies could be observed between twist drills of 2 mm ∅ and conical drills of 3.5, 4.3 and 5 mm ∅. During 10 and 16 mm drilling osteotomies, external irrigation showed significantly higher temperatures (P < 0.05) for all conical drills compared with internal or combined irrigation, respectively. Significantly lower temperatures (P < 0.05) could be detected with internal or combined irrigation for the use of conical drills with various diameters and drilling depths. CONCLUSIONS: This fully standardized bone model provides optimized comparability for the evaluation of bone osteotomies and resulting temperature changes. As regards the efficiency of the various irrigation methods, it could be demonstrated that internal and combined irrigation appears to be more beneficial than external irrigation.
    Clinical Oral Implants Research 01/2013; · 3.43 Impact Factor
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    ABSTRACT: OBJECTIVES: Simultaneous implant placement in conjunction with lateral or transcrestal maxillary sinus floor augmentation gives the benefit of reduction in healing times and surgical interventions. Primary implant stability, however, may be significantly reduced in resorbed residual ridges. Aim of the present study was to investigate the impact of residual bone height, bone density, and implant diameter on primary stability of implants in the atrophic sinus floor. MATERIAL AND METHODS: A total of 66 NobelActive(™) implants were inserted in the sinus floor of fresh human cadaver maxillae: 22 narrow (3.5 mm), 22 regular (4.3 mm), and 22 wide (5.0 mm) diameter implants in residual ridges of 2-6 mm height. Presurgical computed tomographic scans were acquired to assess bone height and density. Primary implant stability was evaluated by insertion torque values (ITV), Periotest values (PTV), and Osstell implant stability quotients (ISQ). RESULTS: Correlations within outcomes (ITV, PTV, ISQ) were highly significant (P < 0.001). Radiographic bone density was found to significantly impact all three outcome measures (P < 0.001), while no influence of residual bone height and implant diameter could be revealed by multifactorial analysis. Consistent results were seen in all subgroups (including residual ridges of 5-6 mm height). CONCLUSIONS: Bone density seems to represent the major determinant of primary stability in maxillary sinus augmentation with simultaneous implant placement (as well as 5-6 mm short implants in the maxillary sinus floor). Preoperative bone density assessment may help to avoid stability-related complications in one-stage implant treatment of the atrophic posterior maxilla.
    Clinical Oral Implants Research 11/2012; · 3.43 Impact Factor
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    ABSTRACT: Prolyl hydroxylase (PHD) inhibitors can induce a proangiogenic response that stimulates regeneration in soft and hard tissues. However, the effect of PHD inhibitors on the dental pulp is unclear. The purpose of this study was to evaluate the effects of PHD inhibitors on the proangiogenic capacity of human dental pulp-derived cells. To test the response of dental pulp-derived cells to PHD inhibitors, the cells were exposed to dimethyloxalylglycine, desferrioxamine, L-mimosine, and cobalt chloride. To assess the response of dental pulp cells to a capping material supplemented with PHD inhibitors, the cells were treated with supernatants from calcium hydroxide. Viability, proliferation, and protein synthesis were assessed by formazan formation, (3)[H]thymidine, and (3)[H]leucine incorporation assays. The effect on the proangiogenic capacity was measured by immunoassays for vascular endothelial growth factor (VEGF). We found that all 4 PHD inhibitors can reduce viability, proliferation, and protein synthesis at high concentrations. At nontoxic concentrations and in the presence of supernatants from calcium hydroxide, PHD inhibitors stimulated the production of VEGF in dental pulp-derived cells. When calcium hydroxide was supplemented with the PHD inhibitors, the supernatants from these preparations did not significantly elevate VEGF levels. These results show that PHD inhibitors can stimulate VEGF production of dental pulp-derived cells, suggesting a corresponding increase in their proangiogenic capacity. Further studies will be required to understand the impact that this might have on pulp regeneration.
    Journal of endodontics 11/2012; 38(11):1498-503. · 2.95 Impact Factor
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    ABSTRACT: PURPOSE: To assess up-to-date expectations and preferences of patients seeking dental implants. MATERIAL AND METHODS: One hundred and fifty consecutive patients (66 male and 84 female interviewees) were asked to rank their concerns regarding implant therapy and answer a questionnaire on implant and bone graft surgery, cost and time considerations and second-opinion behaviour. RESULTS: Treatment predictability and avoidance of removable dentures were ranked high priority (compared with time and cost efficiency or avoidance of bone grafts). Patients' estimation of the 10-year implant success rate was 84%, and 59% of patients expected implants to last for a lifetime. Total treatment time was estimated to be 4 months on average, and only 12% would tolerate increased risk of implant failure for the sake of shortening treatment duration. 61% of interviewees accepted autologous bone grafts (the majority favouring the retromolar area), while only 23% were willing to undergo bone harvesting from the hip. 43% opted for bone substitute material to avoid donor site morbidity. 67% would accept the additional costs associated with computed tomography, software-based treatment planning and guided implant placement to avoid bone graft surgery. Motivation for second-opinion seeking was high (46-62%), especially in young and male patients. CONCLUSION: Patient expectations on implant success and predictability are high compared with their reluctance towards treatment costs and duration. Acceptance of treatment morbidity is high among patients reporting low denture satisfaction; however, minimally invasive treatment alternatives are generally preferred.
    Clinical Oral Implants Research 10/2012; · 3.43 Impact Factor
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    ABSTRACT: OBJECTIVES: The purpose of this study was to evaluate the temperature changes during implant osteotomies with a combined irrigation system as compared to the commonly used external and internal irrigation under standardized conditions. MATERIAL AND METHODS: Drilling procedures were performed on VII bovine ribs using a computer-aided surgical system that ensured automated intermittent drilling cycles to simulate clinical conditions. A total of 320 drilling osteotomies were performed with twist (2 mm) and conical implant drills (3.5/4.3/5 mm) at various drilling depths (10/16 mm) and with different saline irrigation (50 ml/min) methods (without/external/internal/combined). Temperature changes were recorded in real time by two custom-built thermoprobes with 14 temperature sensors (7 sensors/thermoprobe) at defined measuring depths. RESULTS: The highest temperature increase during osteotomies was observed without any coolant irrigation (median, 8.01°C), followed by commonly used external saline irrigation (median, 2.60°C), combined irrigation (median, 1.51°C) and ultimately with internal saline irrigation (median, 1.48°C). Temperature increase with different drill diameters showed significant differences (P < 0.05) regarding drill depth, confirming drill depth and time of drilling as influencing factors of heat generation. Internal saline irrigation showed a significantly smaller temperature increase (P < 0.05) compared with combined and external irrigation. A combined irrigation procedure appears to be preferable (P < 0.05) to an external irrigation method primarily with higher osteotomy depths. CONCLUSIONS: Combined irrigation provides sufficient reduction in temperature changes during drilling, and it may be more beneficial in deeper site osteotomies. Further studies to optimize the effects of a combined irrigation are needed.
    Clinical Oral Implants Research 09/2012; · 3.43 Impact Factor
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    ABSTRACT: OBJECTIVE: Moderately rough, surfaced implants are widely used. Nevertheless data on long-term soft and hard tissue parameters are still conflicting. The purpose of this study was to evaluate peri-implant bone level and soft tissue integration of anodized vs. turned surfaced implants in the anterior mandible after a mean functional loading time of 85 months. METHODS: Of 114 edentulous patients invited for follow-up, 41,2% were available for recall. Forty-seven patients with a mean age of 71 ± 9 years (14 men and 33 women) received 188 dental implants; All patients were edentulous and prosthetic rehabilitation was carried out by a bar-retained overdenture. Radiographic peri-implant bone level was assessed twice at baseline and recall. Clinical examination contained peri-implant sounding (PPD, BoP) and indexing oral hygiene (mPI). RESULTS: From baseline up to 85 months two patients experienced implant loss (four implants), which corresponds to an overall-survival rate of 97.9%. No significant differences were found between implant surfaces concerning the clinical parameters, such as plaque, calculus, bleeding on probing and pocket probing depth. The moderately rough surfaced implants showed significantly less decrease in peri-implant bone level (1.53 ± 0.25 mm) than turned surfaced implants (2.42 ± 0.34 mm) (P = 0.036). The interaction between the position of the implant and surface topography (P = 0.037) as well as the site at the implant (P = 0.004) had a significant influence on bone level changes. CONCLUSION: Both surface topographies with bar-supported overdentures have excellent long-term clinical outcomes. Moreover, a moderately roughened, anodized surface has beneficial effects in the anterior lower jaw.
    Clinical Oral Implants Research 05/2012; · 3.43 Impact Factor
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    ABSTRACT: OBJECTIVES: The aim of this study was to evaluate the prevalence of root resorption of maxillary incisors caused by impacted maxillary canines using low-dose dental computed tomography and to gain additional knowledge of the underlying aetiology and the progression of root resorption. MATERIALS AND METHODS: A total of 440 patients (mean age, 24.7 years) with 557 impacted maxillary canines were examined regarding their location and the occurrence of root resorption of maxillary incisors. RESULTS: The frequency of root resorption was 2 % of central and 7.7 % of lateral maxillary incisors. The location of the 557 impacted canines within the dental arch was palatal in 67.5 %, buccal in 15.4 % and central in 17.1 %. No significant differences could be shown with respect to the width and the shape of the dental follicle of the impacted maxillary canines and the presence of root resorption of incisors. The presence of root resorption of central (p < 0.0001) and lateral (p < 0.023) maxillary incisors was significantly correlated with an existing contact relationship of the impacted maxillary canines. CONCLUSIONS: Our investigation confirms the theory of prior reports comprising a much larger patient population, hypothesising that the dental follicle of impacted maxillary canines does not cause resorption of adjacent maxillary incisors per se. CLINICAL RELEVANCE: Root resorption of maxillary incisors is correlated with effects of contact of the impacted maxillary canines, and these findings should be considered in treatment planning. Our findings are consistent with other reports and may develop new treatment approaches for the treatment of this sequela.
    Clinical Oral Investigations 04/2012; · 2.20 Impact Factor
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    ABSTRACT: To gain further insights and resolve conflicting results in the literature regarding prevalence, predominant location and morphologic variability of maxillary sinus septa. 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. 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 < 0.001). Septa were located in premolar, molar and retromolar regions in 24.4%, 54.6% and 21.0% respectively. Orientation of septa was transverse in 87.6%, sagittal in 11.1% and horizontal in 1.3% of cases. Septa height measured 7.5 mm on average. Complete septa (dividing the sinus into two separate cavities) were found in only 0.3%. Other rare conditions included multiple septa in one sinus (4.2%) and bilateral septa (17.2%). Septa diagnosis using panoramic radiographs yielded incorrect results in 29% of cases. In view of their high overall prevalence and significant morphologic variability, 3D radiographic imaging prior to sinus floor augmentation may help to reduce complication rates in the presence of maxillary sinus septa.
    Journal Of Clinical Periodontology 04/2012; 39(8):769-73. · 3.69 Impact Factor
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    ABSTRACT: OBJECTIVE: Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis. METHODS: Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis. RESULTS: Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology. CONCLUSIONS: The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation.
    Clinical Oral Implants Research 04/2012; · 3.43 Impact Factor

Publication Stats

3k Citations
464.96 Total Impact Points

Institutions

  • 2001–2013
    • Medical University of Vienna
      • Universitätsklinik für Radiodiagnostik
      Wien, Vienna, Austria
  • 2011
    • Athens State University
      Athens, Alabama, United States
  • 1988–2007
    • University of Vienna
      • • Department of Anthropology
      • • School of Dentistry
      Vienna, Vienna, Austria
  • 2006
    • Università di Pisa
      Pisa, Tuscany, Italy
  • 2002
    • Ludwig Boltzmann Institute for Osteology
      Wien, Vienna, Austria