The International Journal of Oral & Maxillofacial Implants, 04/2008

Purpose: One-visit in-office CAD/CAM fabrication of esthetic ceramic crowns as a superstructure for posterior implants is quite new. The aim of the study was to evaluate the strength of esthetic ceramic CAD/CAM crowns with varied occlusal thickness and seated with adhesive and nonadhesive cements on titanium and zirconia abutments. Materials and Methods: Esthetic ceramic CAD/CAM-generated molar crowns (n = 15 per group) with occlusal thicknesses of 0.5 mm and 1.5 mm were seated on titanium (1) and zirconia (2) abutments: noncemented (a) and with nonadhesive cement (b) or 2 adhesive resin-based cements (c) and (d). In addition, 15 molar crowns with 5.5-mm occlusal thickness were seated on short zirconia abutments (3) using cements (c) and (d). All crowns had the identical occlusal morphology and were loaded with a crosshead speed of 0.5 mm/min until fracture. Load data were analyzed using 2-way ANOVA, the Scheffé test, and Weibull probability of failure analysis. Results: Fracture loads of 1.5-mm occlusal thickness crowns (a, b, c, d) were higher (P .001) than those of 0.5-mm crowns (except for group 1d). Occlusal 5.5-mm crowns on short zirconia abutments had similar (2c) or less (2d) strength than the respective 1.5-mm crowns. Nonadhesive crowns (1b, 2b) were weaker (P .001) than adhesive crowns (1c, 1d, 2c, 2d). Fracture loads of 0.5- and 1.5-mm crowns were significantly higher on titanium than on zirconia abutments with both cements. Adhesive cement d generally showed higher fracture loads than c on both titanium and zirconia. Conclusion: Esthetic ceramic CAD/CAM molar implant crowns gained high strength with adhesive cements on both titanium and zirconia implant abutments compared to nonadhesive cementation. Schlagwörter: adhesive cementation, CAD/CAM esthetic ceramic, CAD/CAM implant crowns, fracture load, titanium abutments, zirconia abutments

Purpose: The aim of this study was to compare 2 different methods of assessment of implants at different inclinations (90 degrees and 65 degrees)-with a profilometer and AutoCAD software. Materials and Methods: Impressions (n = 5) of a metal matrix containing 2 implants, 1 at 90 degrees to the surface and 1 at 65 degrees to the surface, were obtained with square impression copings joined together with dental floss splinting covered with autopolymerizing acrylic resin, an open custom tray, and vinyl polysiloxane impression material. Measurement of the angles (in degrees) of the implant analogs were assessed by the same blinded operator with a profilometer and through analysis of digitized images by AutoCAD software. For each implant analog, 3 readings were performed with each method. The results were subjected to a nonparametric Kruskal-Wallis test, with P £ .05 considered significant. Results: For implants perpendicular to the horizontal surface of the specimen (90 degrees), there were no significant differences between the mean measurements obtained with the profilometer (90.04 degrees) and AutoCAD (89.95 degrees; P = .9142). In the analyses of the angled implants at 65 degrees in relation to the horizontal surface of the specimen, significant differences were observed (P = .0472) between the mean readings with the profilometer (65.73 degrees) and AutoCAD (66.25 degrees). Conclusions: The degrees of accuracy of implant angulation recording vary among the techniques available and may vary depending on the angle of the implant. Further investigation is needed to determine the best test conditions and the best measuring technique for determination of the angle of the implant in vitro. Schlagwörter: dental implants, prostheses, software validation, systems analysis

Purpose: To investigate the micromotion between the implant and surrounding bone caused by the implementation of an angled abutment for an immediately loaded single dental implant located in the anterior maxilla. Materials and Methods: A simplified half premaxillary bone model was fabricated. The dimension of the alveolar ridge was adopted from a dry human skull. Based on Brånemark protocol for Mk IV implants in type-3 bone, an immediate loading model was developed by press-fitting a 4-mm-diameter cylinder implant into a 3.15-mm osteotomy site in a numeric model. Material properties were assigned to the simulated model, and the model was meshed. A bite force of 89 N was applied to the tops of the 0-degree, 15-degree, and 25-degree angled abutments at a 120-degree angle to the abutment long axis. The micromotion between the bone-implant interfaces was calculated using ANSYS 9.0 software featuring a nonlinear contact algorithm. Results: The micromotion values for 15-degree and 25-degree angled abutments were 119% and 134%, respectively, compared to the corresponding values for straight abutments. Compared to straight abutments, the 25-degree abutments resulted in increased maximum von Mises stresses to a level of 18%. Most of the stresses were concentrated within the cortical bone around the neck of the implants. Conclusion: Within the limits of the present finite element analysis study, abutment angulation up to 25 degrees can increase the stress in the peri-implant bone by 18% and the micromotion level by 30%. Schlagwörter: angled abutment, finite element analysis, immediate loading, micromotion

Purpose: This study was undertaken to investigate surface properties of surface-modified titanium implants in terms of surface chemistry, morphology, pore characteristics, oxide thickness, crystal structure, and roughness. Materials and Methods: An oxidized, custom-made Mg implant, an oxidized commercially available implant (TiUnite), and a dual acid-etched surface (Osseotite) were investigated. Surface characteristics were evaluated with various surface analytic techniques. Results: Surface chemistry showed similar fingerprints of titanium oxide and carbon contaminant in common for all implants but also revealed essential differences of the elements such as about 9 at% Mg for the Mg implant, about 11 at% P for the TiUnite implant and about 12 at% Na for the Osseotite implant. Surface morphology of the Mg and TiUnite implants demonstrated a duplex oxide structure, ie, an inner barrier layer without pores and an outer porous layer with numerous pores, whereas the Osseotite implant revealed a crystallographically etched appearance with pits. The diameter and depth of pores/pits was = 2 µm and = 1.5 µm in the Mg implant, = 4 µm and = 10 µm in the TiUnite implant, and = 2 µm and = 1 µm in the Osseotite implant, respectively. Oxide layer revealed homogeneous thickness, about 3.4 µm of all threads in the Mg implants. On the contrary, TiUnite showed heterogeneous oxide thickness, about 1 to 11 µm, which gradually increased with thread numbers. Crystal structure showed a mixture of anatase and rutile phase for the Mg implants. With respect to roughness, Sa showed 0.69 µm in the Mg implant, 1.35 µm in the TiUnite implant, and 0.72 µm in the Osseotite implant. Conclusions: Well-defined surface characterization may provide a scientific basis for a better understanding of the effects of the implant surface on the biological response. The surface-engineered implants resulted in various surface characteristics, as a result of different manufacturing techniques. Schlagwörter: acid-etched surface, characterization of surface properties, oxidized Mg-incorporated surface, titanium implant

Purpose: To investigate the effect of chemically modified implants with similar microtopographies but different nanotopographies on early stages of osseointegration. Materials and Methods: Forty screw-shaped implants were placed in 10 New Zealand white rabbits. The implant surface modifications investigated in the present study were (1) blasting with TiO2 and further (2) fluoride treatment or (3) modification with nano-hydroxyapatite. Surface evaluation included topographical analyses with interferometry, morphologic analyses with scanning electron microscopy, and chemical analyses with x-ray photoelectron spectroscopy. Bone response was investigated with the removal torque test, and histologic analyses were carried out after a healing period of 4 weeks. Results: Surface roughness parameters showed a slight decrease of the average height deviation for the fluoride-treated compared to the blasted (control) and nano-hydroxyapatite implants. Scanning electron microscopic images at high magnification indicated the presence of nanostructures on the chemically modified implants. Chemical analyses revealed the presence of titanium, oxygen, carbon, and nitrogen in all implant groups. The blasted-fluoride group revealed fluoride, and the blasted-nano HA group calcium and phosphorus with simultaneous decrease of titanium and oxygen. Removal torque values revealed an increased retention for the chemically modified implants that exhibit specific nanotopography. The histologic analyses demonstrated immature bone formation in contact with the implant surface in all groups, according to the healing period of the experiment. Conclusion: Chemical modifications used in the present study were capable of producing a particular nanotopography, and together with the ions present at the implant surface, may explain the increased removal torque values after a healing period of 4 weeks. Schlagwörter: dental implants, hydroxyapatite, nanotopography, osseointegration, surface modification, titanium fluoride

Purpose: Passive fit is difficult to achieve in implant-supported restorations with existing superstructure fabrication techniques. The aim of the study presented was to investigate whether computer-generated fixed partial dentures (FPDs) based on optical impressions lead to less strain development than conventionally fabricated FPDs. Materials and Methods: A measurement model with 2 implants was set up and strain gauges were attached to the model material mesially and distally adjacent to the implants. Two groups of conventional cementable restorations based on repositioning and pick-up impressions, respectively, and 1 group of CAD/CAM-generated FPDs based on optical impressions were fabricated (n = 10). Strain development during FPD fixation was recorded. In order to compare the different FPD groups with one another, a multivariate analysis of variance (MANOVA) was performed at a level of significance of a = .05. Results: The mean strain development at the different strain gauge locations ranged from 80.38 µm/m to 437.11 µm/m. The 2 groups of conventionally fabricated FPDs showed no significant difference in terms of strain development (P = .07). The CAD/CAM-fabricated FPDs revealed a significantly lower strain development than those made from pick-up technique impressions (P = .01). No significant difference could be detected between the FPDs manufactured from repositioning technique impressions and the CAD/CAM-generated restorations (P = .19). Conclusion: Within the limitations of the study presented, it can be concluded that restorations fabricated on the basis of optical impressions demonstrate a level of fit which is at least as passive as that of conventional FPDs. Schlagwörter: CAD/CAM, implant-supported restoration, impression accuracy, passive fit

Purpose: Two polymorphisms in the promoter region of human MMP-1 gene, an insertion of a guanine at position -1607 and A-519G substitution, have been shown to increase the transcriptional activity of these matrix metalloproteinases (MMPs). The objective of this study was to investigate the possible relationship between these polymorphisms and early implant failure. Materials and Methods: A sample of 104 nonsmokers was divided into 2 groups: a test group comprising 44 patients with 1 or more early failed implants and a control group consisting of 60 individuals with 1 or more healthy implants. Genomic DNA from oral mucosa was amplified by polymerase chain reaction and analyzed by restriction endonucleases. The significance of the differences in observed frequencies of polymorphisms were assessed by x2 tests. Results: The G-1607GG polymorphism with the genotype G/G was observed at a frequency of 62% in the control group, while in the test group this genotype was noted in 34% of the individuals (P = .011). The allele G was found at a frequency of 75% in control group and 61.66% in the test group (P = .05). No significant differences were seen in the genotypes and allele frequencies in the A-519G polymorphism among the groups (P = .064 and P = .124, respectively). The distribution of the haplotypes arranged as alleles and genotypes showed a significant difference between control and test groups (P = .031 and P = .002, respectively). Conclusion: On the basis of this study of 60 patients who experienced no implant failure and 44 patients who experienced implant failure, the results suggest that G-1607GG polymorphism in MMP-1 gene is associated with early implant failure, while A-519G polymorphism in MMP-1 gene does not show a significant relationship with implant loss. This study also suggests that haplotypes G-1607GG and A-519G of MMP-1 may be associated with the osseointegration process.

Purpose: Anodic spark deposition techniques have been effectively applied to achieve a microporous morphology on metals. To investigate the effect of a new anodic spark deposition-based treatment in the enhancement of titanium implant osseointegration in trabecular bone of aged and ovariectomized sheep, a histomorphometric and microhardness study was carried out. Materials and Methods: Ten sheep were divided into 2 groups. Five were submitted to a bilateral ovariectomy to induce an estrogen-deficiency osteopenia (Ovariectomized), and 5 were left untreated (Aged). Twenty-four months later, they underwent a bilateral implantation of commercially pure titanium screw threads in the lateral surface of femoral condyles: electrochemically treated titanium (SP) and acid-etching treated titanium (BioRough). Twelve weeks after the second operation, the animals were sacrificed and femur segments and iliac crest biopsy specimens were examined for histomorphometric and microhardness evaluations. Results: The histomorphometry of the trabecular bone of the iliac crest biopsy specimens and that around screws showed marked signs of bone rarefaction in the Ovariectomized group when compared to the Baseline and Aged groups. Significantly greater bone-implant contact was observed for SP implants in comparison with BioRough implants in both the Aged (P .001) and Ovariectomized (P .01) groups. No significant differences in terms of microhardness were found between SP and BioRough implants within the Aged group, while a significantly higher Bone Maturation Index was observed for SP in the Ovariectomized group (P .05). Conclusions: The novel electrochemical treatment SP produced the most promising results and was able to introduce substantial improvements in achieving the fast and stable osseointegration of implants in osteopenic bone. Schlagwörter: anodic spark deposition, electrochemical, osteopenia, titanium

Purpose: The aim of this study was to compare implant cast accuracy as a function of impression technique, closed tray impressions using indirect, metal impression copings at the implant level or direct, plastic impression caps at the abutment level, and impression material viscosity combinations. Materials and Methods: A stainless steel master model with three implant replicas was utilized to produce Type IV stone casts. Master model impressions were made using closed trays at the implant level with screw-on metal impression copings (indirect/implant level) or at the abutment level with snap-on plastic impression caps (direct/abutment level). With both techniques, either medium-body or heavy-body polyether impression material was syringed around the implant impression coping or abutment impression cap with medium body material in a custom tray. Twenty casts were produced with 5 casts in each test group. A measuring microscope (0.001 mm accuracy) was used to measure cast inter-implant or inter-abutment distances. Cast accuracy was calculated based on the percent difference of the measurements as compared to the master model. Results: A repeated measures 2-factor ANOVA (a = .05) indicated no significant difference in cast accuracy as a function of impression viscosity. However, cast accuracy was significantly different between casts made with indirect/implant level versus direct/abutment level impressions. With the plastic impression caps, the cast inter-abutment distances were larger than the master model, with mean percent differences of 0.19% to 0.24% across the 3 measurement sites. In contrast, with the metal impression coping impressions, the cast inter-implant distances were almost equal to or slightly smaller than the master model, with mean percent differences -0.06% to 0.02%. Conclusions: Impression material viscosity does not appear to be a critical factor for implant cast accuracy. However, casts made with indirect, metal impression copings might be more accurate than casts made with direct, plastic impression caps. This could be an especially important factor with casts used to fabricate multiple-implant restorations. Schlagwörter: closed tray direct impressions, closed tray indirect impressions, dental implants

Purpose: The purpose of this study was to compare properties of roughened and polished titanium with respect to their ability to attach to cells and bind to protein as well as their cell spreading behavior. Materials and Methods: Three different titanium surface treatments were compared for their ability to support cell attachment and spreading: sandblasted and acid-etched, resorbable blast media, and machine-polished titanium. The surface of the materials was characterized for surface roughness, surface energy, and surface chemistry. Osteoblast-like MG-63 cells were tested for in vitro attachment and spreading in the presence of serum proteins. Cell attachment was assessed by direct counting, dye binding, and microculture titanium assays. Cell spreading was determined by measuring area/cell in phalloidin-AlexaFluor 488 stained cells. Absorption of bovine serum albumin was determined by assay. Results: Scanning electron micrography and x-ray diffractometry confirmed increased surface roughness of the roughened materials. All 3 materials had similar albumin binding kinetics. Three different methods confirmed that roughened surfaces enhance early cell attachment to titanium in the presence of serum. Cells spread better on smoother machined surfaces than on the roughened surfaces. Conclusion: Roughened titanium surfaces exhibited better early cell attachment than smooth surfaces in the presence of serum. The cells attached to roughened titanium were less spread than those attached to machined titanium. Although albumin binding was not different for roughened surfaces, it is possible that roughened surfaces preferentially bound to serum adhesive proteins to promote early cell attachment. Schlagwörter: cell attachment, implant, spreading, titanium

Purpose: The purpose of this study was to systematically review clinical studies on the incidence of abutment screw loosening in single-implant restorations with different implant-abutment connection geometries. Materials and Methods: The literature search was conducted using several electronic databases. Specific terms were used for the database search, which spanned the years 1990 to 2006. The search was augmented by using the option of "related articles" as well as hand searching of references and relevant journals. Relevant studies were selected according to predetermined inclusion and exclusion criteria. Agreement between reviewers was determined by using Cohen's kappa coefficients. Three-year complication-free rates (survival proportions) were calculated with the aid of a survival function, assuming constant failure rates. Summary estimates per group for complication-free rate after 3 years (M-estimator) were calculated using Tukey's biweight estimator. Results: The initial database search yielded 1,526 relevant titles. After the subsequent filtering process, 27 studies were finally selected. Interexaminer agreement ranged from good to perfect. The external-connection group comprised 12 studies following 586 single-implant restorations for a mean follow-up time that ranged from 3 to 5 years. The estimated percent of complication-free single-implant restorations after 3 years was 97.3% (95% CI: 95.6-98.3). The internal connection group comprised 15 studies following 1,113 single-implant restorations for a mean follow-up time that ranged from 3 to 10 years. The estimated percentage of complication-free single-implant restorations after 3 years was 97.6% (95% CI: 96.5-98.3). Conclusion: The results show that abutment screw loosening is a rare event in single-implant restorations regardless of the geometry of implant-abutment connection, provided that proper antirotational features and torque are employed. Schlagwörter: implant complications, implant geometry, meta-analysis, screw loosening, single implants

Purpose: Zirconia ceramics, a biocompatible material with favorable mechanical properties, has been suggested for use in the manufacture of dental implants instead of the commonly used titanium. Not much data exist on the early healing response around zirconia dental implants. The aim of this study was to give a descriptive histologic assessment of the degree of early bone apposition around zirconia dental implants at 2 and 4 weeks after insertion compared to surface-modified titanium implants. Materials and Methods: Four zirconia and 4 titanium implants were placed in New Zealand white male rabbits. One implant was inserted in the condyle of each distal femur. Specimens were harvested at 2 and 4 weeks and processed with light microscopic analysis. The area of bone-implant contact was evaluated histomorphometrically. Results: A high degree of bone apposition could be observed on all implants at both time points. Differences in the percentage of implant surface covered with bone were noted between the 2 time points, with comparable results for the 2 materials. Conclusion: The results of this limited histologic study demonstrate a similar rate of bone apposition on zirconia and surface-modified titanium implant surfaces during early healing. To confirm these results, further studies need to be conducted, involving larger sample size at more time points. Schlagwörter: early healing, implants, osseointegration, zirconia

Purpose: The aim of this 5-year prospective evaluation was to assess the bone and peri-implant mucosa responses at unsplinted, microthread implants supporting mandibular overdentures and to determine patient responses to therapy. Materials and Methods: Two implants were placed by a 1-stage procedure in the parasymphyseal mandibles of 59 subjects. Implant placement was followed by immediate insertion of overdentures without connection to abutments. After 3 months, connection using Dalla Bona attachments was made and peri-implant mucosa, peri-implant bone, and patient perceptions of treatment were evaluated. Results: The implant success rate was 95.9% from 6 to 60 months. The changes in marginal bone levels were positive (bone gain) but did not reach statistical significance at 12, 36, or 60 months (+0.13 ± 0.59 mm, +0.23 ± 0.66 mm, and +0.09 ± 0.79, respectively). Treatment was viewed as effective; patients rating satisfaction with their teeth increased from a preoperative level of 12.1% to 94.6% at overdenture abutment connection and remained high (81.6%) after 5 years. Conclusions: Expedited mandibular overdenture therapy utilizing unsplinted, microthreaded mandibular parasymphyseal implants was associated with high implant survival, preservation of crestal bone, and high patient satisfaction. Complications were minor and related to prosthodontic features of therapy. Schlagwörter: dental implant, mandibular edentulism, microthread, patient satisfaction

Purpose: The aim of this multicenter study was to evaluate implant success and restorative complications of cement-retained implant-supported anterior partial prostheses in Jordan. Materials and Methods: A retrospective study of all implants with a minimum of 1-year follow-up were used to support fixed, cement-retained restorations from April 2000 until March 2007. The cement-retained implants were loaded with either single- or multiple-tooth replacements. The Fisher exact test was performed to test the presence of any statistically significant difference in success concerning gender or arch of placement. Results: Eighty-seven implants were placed in the anterior region of the mandible or maxilla in 49 patients at multiple clinical practices in Jordan. The age of the patients ranged from 17 to 85 years. Eighteen implants were placed in the mandible and 69 in the maxilla. Three maxillary implants in 2 male patients had 3-mm horizontal bone loss. Those 3 implants are still functioning and were considered surviving implants but not successful implants. Therefore, the implant cumulative survival rate for both arches and genders was 100%. The implant cumulative success rate was 95.78%. Three crowns (maxillary) were dislodged. No significant differences were revealed regarding gender or arch of placement (P > .05). Conclusions: Cement-retained implants exhibited high survival and success rates among a Jordanian population. Schlagwörter: cement, implant-supported prosthesis, restorative problems, success rate, survival rate

Purpose: To assess the clinical effectiveness of immediate nonfunctional loading for single-tooth implants placed in the anterior maxilla following augmentation with cancellous freeze-dried block graft. Materials and Methods: The clinical outcomes of immediately nonfunctionally loaded implants up to 18 months after placement in the anterior maxilla were evaluated in 11 consecutive patients. Implants were immediately restored with unsplinted acrylic resin provisional crowns. Follow-up was monthly, and intraoral radiographs were obtained immediately after implant placement and at 6, 12, and 18 months. Survival rate and radiographic marginal bone loss were evaluated at 0, 6, 12, and 18 months. In the anterior maxilla, 12 implants were placed. Results: Marginal bone loss did not extend beyond the first thread up to 18 months follow-up, and the survival rate was 100%. Conclusion: Within the limits of the present study, immediate nonfunctional loading for single-tooth implants placed in the anterior maxilla following augmentation with cancellous freeze-dried block graft seems a promising treatment alternative. (Case Series)

Purpose: The aim of this study was to evaluate the use of provisional implants, which can provide patients with provisional fixed partial dentures during the healing time of augmentation procedures and/or during the osseointegration period of definitive implants until delivery of the definitive prosthesis. Materials and Methods: Thirty-one patients were consecutively included in the study. Eighteen patients (group A, primary simultaneous group) were initially treated simultaneously with provisional and definitive implants and provided with 18 interim fixed partial dentures. Thirteen patients (group B) received provisional implants in a staggered procedure. In the first stage of group B patients (augmentation phase), provisional implants were placed to bridge the augmentation phase and for anchoring 13 interim fixed partial dentures. In the second stage (secondary simultaneous group), patients of group B received provisional implants to bridge the osseointegration phase for simultaneously placed definitive implants by further use of 13 interim fixed partial dentures. All patients were followed from provisional implant and definitive implant placement to delivery of the definitive prosthesis. Loss of provisional implants and interim fixed partial dentures was noted, and stability of provisional implants was evaluated using the Periotest device. The procedures of immediate rehabilitation with fixed partial dentures using provisional implants were subjectively rated by patients with regard to satisfaction, treatment period, and acceptance. Results: In 31 patients, 44 provisional fixed partial dentures were supported by 98 provisional implants. No provisional implant loss in group A or group B-second stage was observed. Only 3 (3%) provisional implants were lost in group B-first stage during the augmentation phase. Incidence (90.8% versus 9.2%) and stability (Periotest values: 8.6 ± 3.9 versus 4.8 ± 2.7) of provisional implants differed significantly between maxilla and mandible (P .01). All interim fixed partial dentures (n = 44) remained in place for the intended time period but in 3 cases with provisional implant loss they were shortened. No definitive implant loss (n = 94, survival: 100%) and especially no implant loss in cases of maxillary sinus augmentation was seen. The items rated showed high satisfaction and good acceptance of the intensive surgical and prosthodontic program. Conclusion: This clinical review showed that (1) provisional implants can successfully provide patients with a fixed partial denture for immediate rehabilitation to bridge the osseointegration or augmentation phase, even in cases with an initially compromised bone situation and (2) although treatment is elaborate, the selected patients decided on a fixed interim rehabilitation with provisional implants rather than on a removable solution. Schlagwörter: immediate rehabilitation, partially edentulous jaw, provisional implants

Purpose: The aim of this study was to evaluate the success rate of 2 different implant systems with sandblasted and acid-etched modified surfaces loaded after reduced healing periods. Materials and Methods: One-hundred seventeen patients with a mean observation period of 3.75 years (24 to 61 months) were included in this evaluation. Chart reviews of a standardized recall program were evaluated. All 532 placed implants showed an unloaded healing time of 6 weeks in the mandible and 12 weeks in the maxilla. At abutment placement a torque value of 35 Ncm was one of the primary variables, and the success of the implants over time was determined by the criteria of Buser et al. The survival was analyzed using Kaplan-Meier method, and the probability of an event within 1 group independent of time was evaluated using the chi-square test and Fisher exact test. Results: Of the 532 implants, 235 were placed in female and 297 in male patients; 448 implants were located in the maxilla and 84 in the mandible. Three implants were lost prior to abutment connection in 3 patients. Life table analyses show an overall success rate of 99.4% at 5 years, as no implants were lost after abutment connection. There was no significant association of the implant type (P = .185), gender (P = .99), or jaw (maxilla/mandible; P = .06) and the survival of the implants within this study. Conclusion: Based on the data found in this investigation, it can be concluded that implants with sandblasted, acid-etched surfaces can be restored after a 6- to 12-week healing period with a high predictability of success. Schlagwörter: reduced healing period, sand-blasted and acid-etched

Purpose: This 5-year follow-up report presents the outcome of early and delayed placement of single-tooth implants. Materials and Methods: An implant was placed on average 10 days after tooth extraction in 23 patients (early) and 3 months after tooth extraction in 22 patients (delayed). All implants were placed in the anterior or premolar regions of the maxilla or mandible. Survival rates, prosthodontic complications, probing pocket depths (PPDs), marginal bone levels measured on radiographs (MBLs), soft tissue appearance (papilla dimensions and clinical crown height), and patient satisfaction were evaluated during an observation period of 5 years. Several patients with prior generalized gingival recession were included in the study, and modification of the papilla scoring was made in these cases. Results: Two implants in the early group and 1 in the delayed group failed before occlusal loading. No further implants were lost during the follow-up period. The mean PPD varied from 3.3 to 4.5 mm in the early group and from 3.6 to 4.4 mm in the delayed group 5 years after implant placement. During the 5-year period, an annual marginal bone loss of less than 0.2 mm was found in both groups. Although the early group performed slightly better than the delayed group as to soft tissue appearance just after seating of the implant restoration, the papilla dimensions and the clinical crown height improved spontaneously over time, and no significant differences between the 2 protocols were seen after 5 years. Furthermore, patients in both groups were highly satisfied with the outcome of their implant treatment. Conclusion: The outcomes of early and delayed placement of single-tooth implants were comparable in terms of high survival rates, few prosthetic complications, acceptable MBLs and PPDs, as well as soft tissue appearance and patient satisfaction during a 5-year follow-up period. Schlagwörter: delayed implant placement, early implant placement, patient satisfaction, prosthetic complications, soft tissue appearance

Purpose: To investigate the effect of type-2 diabetes on implant survival and complication rate. Materials and Methods: Prospective study enrolling type-2 diabetic patients suffering from edentulism, having a mean perioperative HbA1c level of 7.2%, and compliant with a maintenance program. All the patients underwent dental and periodontal examinations and had laboratory testing for HbA1c, fasting plasma glucose, blood lipids, and microalbuminuria. Nondiabetic patients matched for implant treatment indication served as controls. The influence of clinical diabetes-related factors and periodontal parameters (Plaque Index, bleeding on probing, probing depth) on implant survival were assessed via univariate then multivariate methods. Results: Forty-five diabetic patients, followed for 1 to 12 years, mean age 64.7 years, received 255 implants: 143 following a classical protocol and 112 in cases of sinus floor elevation, immediate loading, and guided bone regeneration. Forty-five nondiabetic control patients received 244 implants: 142 following a classical protocol and 102 in cases of advanced surgery. Implant survival following conventional or advanced implant therapy was not statistically different between the well-controlled (HbA1c 7%, P = .33) and the fairly well-controlled group (HbA1c 7% to 9%, P =.37). The overall survival rate for the diabetic group was 97.2% (control 98.8%) and was not significantly different for age, gender, diabetes duration, smoking, or type of hypoglycemic therapy. The mean peri-implant bone loss was 0.41 ± 0.58 mm (control, 0.49 ± 0.64 mm). PI and BOP fairly correlated with postoperative complications. HbA1c was the only multivariate independent factor affecting the complication rate (P = .04). No statistically significant difference was found for patients (P = .81) or for implants (P = .66) for the advanced surgery cases or the conventional approach in diabetic patients compared to nondiabetic patients. Schlagwörter: diabetes, diabetes control, HbA1c, implant therapy, type-2 diabetes

Purpose: The aim of this study was to report a clinical comparative assessment of crestal bone level change around single implants in fresh extraction sockets in the esthetic zone of the maxilla either immediately loaded or loaded after a delay. Materials and Methods: Forty patients were included in a prospective, randomized study. All patients required 1 tooth extraction (ie, 1 tooth with a hopeless prognosis) and were randomized into either the test group or the control group. Implants were positioned immediately after tooth extraction and were loaded immediately in the test group (20 implants) and after 3 months in the control group (20 implants). The implant site was prepared, with at least 4 mm of sound apical bone below the implant apex, and the coronal margin of the implant was placed at the buccal level of the bone crest. All implants were 13 mm long; 30 implants had a diameter of 5 mm, and 10 had a diameter of 3.75 mm. Radiographic examinations were made at baseline, at 6 months, and at 24 months. To compare the mean values between test and control group, a paired t test was performed (considered statistically significant at P .05). Results: After a 24-month follow-up period, a cumulative survival rate of 100% was reported for all implants. The control group resulted in a mean mesial bone loss of 1.16 ± 0.32 mm and a mean distal bone loss of 1.17 ± 0.41 (mean bone loss, 1.16 ± 0.51 mm). The test group resulted in a mesial bone loss of 0.93 ± 0.51 mm and a distal bone loss of 1.1 ± 0.27 mm (mean bone loss, 1.02 ± 0.53 mm). No statistically significant difference between control and test groups (P > .05) was found. Conclusion: The success rate and radiographic results of immediate restorations of dental implants placed in fresh extraction sockets were comparable to those obtained in delayed loading group. Schlagwörter: dental implants, immediate loading, postextraction sockets

Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance throughout the treatment period. Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited. Recently, novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides in an attempt to improve precision of implant placement. The aim of this case report was to show a modified surgical template used throughout implant placement as an alternative to a conventional surgical guide. (Case Report) Schlagwörter: computerized tomography, dental implants, immediate function/loading, stereolithography, surgical templates