Evaluation of two printing techniques for maxillary removable partial denture frameworks.

STATEMENT OF PROBLEM: Three-dimensional (3D) printing technology has gained popularity in producing removable partial denture (RPD) frameworks, including direct 3D printing of the metal framework and framework printing using castable resin, subsequently cast and processed. However, whether the technology is sufficiently accurate and precise to supersede traditional methods is unclear. PURPOSE: The purpose of this in vitro study was to determine the accuracy and precision of 2 different methods in the fabrication of RPD frameworks, including 3D printing by selective laser melting (SLM) and digital light processing (DLP). MATERIAL AND METHODS: Maxillary casts were digitized to design RPD frameworks. Thereby, 8 frameworks were produced for each group. The SLM group underwent a thermal finishing process after printing. In the DLP group, castable resin was printed but not cast. All frameworks were scanned to generate digital files, which were then compared with the original design using a metrology software program and manual measurements. Statistical analysis was executed using the t-test for independent specimens (α=.05) and by comparing heatmaps of the overlaid meshes. RESULTS: The analysis of the frameworks indicated minor deviations across all specimens. Regarding accuracy, there were no significant differences between the groups (P=.986). The SLM frameworks demonstrated greater precision, with absolute deviation values of 0.13 mm compared with 0.17 mm in the DLP group (P<.001). CONCLUSIONS: The findings underscored a high consistency between the 2 printing techniques, demonstrating a sufficiently advanced production process to yield predictable results. While the accuracy of both techniques was at a comparably high level and did not differ significantly, the SLM technique delivered RPDs with higher precision.

Eleven- to fifteen-year outcome for two-piece implants with an internal tube-in-tube connection: a cross-sectional analysis of 245 implants.

PURPOSE: The aim of this retrospective study was to evaluate the outcomes of a two-piece implant system with a tube-in-tube internal connection after up to 15 years of clinical use. MATERIAL AND METHODS: A retrospective follow-up examination of patients treated with internal tube-in-tube implants between 2003 and 2006 was conducted. The implant survival rates, peri-implant conditions (marginal bone loss, bleeding on probing, plaque index, probing depth), and technical complications were determined. RESULTS: In total, 312 dental implants were placed in 152 patients. Of the original 152 patients enrolled, 245 implants in 112 patients were available for a follow-up evaluation after 11 to 15 years (mean observation time, 12.9 ± 1.1 years). The overall implant survival rate was 93.9%. Outcomes for MBL (1.49 ± 1.23 mm), PI (24.3 ± 22.2%), BOP (18.3 ± 28.7%), and PD (2.74 ± 1.21 mm) were observed. Selected parameters (time after implant surgery, smoking habits, bone augmentation (GBR)) showed an influence on MBL and PD. CONCLUSIONS: The internal tube-in-tube implant system showed favorable long-term results. The correlation of MBL and PD with the patient-specific factor smoking habit is in accordance with other studies. CLINICAL RELEVANCE: Camlog Root-Line implants with a tube-in-tube implant-abutment connection and a 1.6-mm polished neck configuration have demonstrated favorable long-term outcomes in daily clinical practice. However, it is important to note that these implants are no longer available on the market.

A randomized clinical trial of phycogenic materials for sinus grafting with hydroxyapatite versus biphasic calcium phosphate: 2 years clinical outcomes.

OBJECTIVES: To assess in a prospective randomized trial two phycogenic bone substitutes-biphasic calcium phosphate (BCP) versus almost pure hydroxyapatite (HA)-for their volume stability and clinical implications after sinus floor elevation (SFE). MATERIALS AND METHODS: Twenty patients requiring lateral-window SFE 6 months prior to implant surgery were randomized to a BCP or HA group. As primary outcome, the grafts were analyzed for volume stability, using four cone-beam computed tomography scans obtained immediately/6/12/24 months after SFE. Secondary outcomes were implant survivval, success, periotest values, oral-health-related quality of life (OHIP-G14), and pain (VAS). RESULTS: Kolmogorov-Smirnov goodness-of-fit test revealed normal distribution of samples (p = .200). At 6/12/24 months, the augmented volumes decreased to 96/92/90% (HA) or 99/96/96% (BCP). Volume changes were significantly a factor of time (p < .001; generalized linear model with repeated measures) and reached significantly lower values in HA group (p = .018). Significant intergroup difference in volume losses was notable at 24 months (p = .021; t-test for independent samples). Periotest values decreased from -3/-4.1 (HA/BCP) after implant placement to -6.3/-4.5 (HA/BCP) after 6 months. OHIP scores diverged at 2 months (HA: 9.5; BCP: 5.2) and largely resolved by 24 months (HA: 1.3; BCP: 1.9). VAS scores were comparable, 2.2 at 1 week after SFE being their highest mean level. CONCLUSIONS: After 2 years, both groups experienced no biological or technical complications, demonstrating a consistent healing trajectory without notable symptoms. Although no significant differences were observed in implant stability and survival, BCP demonstrated higher volume stability than HA.

Phycogenic bone substitutes for sinus floor augmentation: Histomorphometric comparison of hydroxyapatite and biphasic calcium phosphate in a randomised clinical pilot study.

Aims: While numerous materials are available for sinus floor elevation, plant-based alternatives still hold promise of overcoming concerns about allogeneic or xenogeneic materials. Thus, the present authors designed a randomised clinical trial to histologically compare an almost pure hydroxyapatite (HA) to a biphasic calcium phosphate comprising 80% ß-tricalcium phosphate (ß-TCP) and 20% hydroxyapatite (ß-TCP/HA), all of phycogenic origin. Materials and methods: Twenty patients scheduled for lateral window sinus floor elevation were randomised to either an HA or a ß-TCP/HA group. Biopsy specimens were taken 3 months after sinus floor elevation and during implant surgery after 6 months. One ground section per biopsy specimen (N = 40) was stained, scanned and histomorphometrically analysed for new bone, old bone, soft tissue, graft, bone infiltration of graft, bone-to-graft contact and penetration depth. Results: At 6 months, more new bone was seen in the ß-TCP/HA group (P = 0.011), whereas more residual graft was present and in more extensive contact with new bone in the HA group. More pronounced alterations, and smaller particle sizes, of graft surrounded and infiltrated by bone were seen in the ß-TCP/HA group. The less extensive bone-to-graft contact in the ß-TCP/ HA group reflected a more advanced state of resorption, while infiltration of residual graft material by bone was also increased in this group. Conclusions: Proper healing was seen in both groups, with the graft materials guiding the formation of new bone, which grew especially well through the particles of the highly osteoconductive and resorptive ß-TCP/HA material. HA was very stable, without significant resorption, but was extensively in contact with new bone after 6 months.

Immediate occlusal vs nonocclusal loading of implants: A randomized prospective clinical pilot study and patient centered outcome after 36 months.

BACKGROUND: Immediate provisionalization reduces chair time and improves patient comfort. PURPOSE: To analyze immediate functional loading vs nonfunctional loading with restorations in the posterior mandible for marginal bone defects, implant success/survival, and patient satisfaction. MATERIALS AND METHODS: A randomized controlled clinical trial was designed to assess these parameters based on 20 adult patients who underwent implant surgery, followed by immediate delivery of screw-retained or cemented single or splinted restorations in full occlusal contact or in infraocclusion (test and control group). A questionnaire with visual analog scales was used to assess patient satisfaction. RESULTS: Following 36-month data were evaluable for 9 patients (21 implants) in the study group (immediate functional loading) and for 10 patients (31 implants) in the control group (immediate nonfunctional loading). One implant in the control group was lost, hence the overall implant survival and success rate was 98.2%. Marginal bone defects were consistent with previous studies and comparable in both groups. Periotest values did not significantly change from baseline and the 12-month follow-up (Friedmann test). Patient satisfaction was high and did not involve any significant intergroup differences (Mann-Whitney U-test). CONCLUSIONS: Both types of immediate provisional restorations are viable in selected patients. Larger randomized controlled trials are needed to establish immediate functional loading as a standard treatment for partially edentulous jaws.

All-ceramic restoration of zirconia two-piece implants--a randomized controlled clinical trial.

OBJECTIVES: Aim of this controlled prospective randomized study was to evaluate the outcome of two-piece zirconia implants compared to titanium implants over a period of up to 24 months. MATERIAL AND METHODS: A total of 31 implants (16 zirconia/Ziterion vario Z(®) + 15 titanium/Ziterion vario T(®) ) were inserted primary stable (>30 Ncm) in the maxilla (7) and mandible (24) of 22 patients (13 male, nine female) requiring neither bone nor soft tissue augmentation. After a healing period of 6 months in the maxilla and 4 months in the mandible, ceramic abutments were luted adhesively to the zirconia implants and definitive all-ceramic restoration was performed with high-density ceramics. Radiographic bone levels, condition of the peri-implant mucosa, aesthetic outcome, implant survival and success were recorded for up to 24 months. RESULTS: Measurements of mean marginal bone levels 24 months after surgery showed a significant bone loss (P < 0.001) in both groups (Ti: 1.43 (SD ± 0.67) vs. Zir 1.48 (SD ± 1.05). One zirconia implant was lost 8 months after restoration. No further complications were recorded, giving an overall survival and success rate of 93.3% for zirconia and 100% for titanium implants after a period of up to 24 months. CONCLUSIONS: After 24 months, success rates of the two-piece ceramic implants showed no significant difference compared to control two-piece titanium implants. The bonded zirconia implant abutment connection appears to be capable with clinical application over the observed period. However, further control measurements need to confirm the presented data.

Immediate Occlusal versus Non-Occlusal Loading of Implants: A Randomized Clinical Pilot Study.

BACKGROUND: Immediate occlusal and non-occlusal loading protocols have been discussed and, despite varying success rates, are considered viable in selected cases. Preoperative implant planning and intraoperative transfer are essential to the success of implant-supported reconstructions in partially or completely edentulous jaws. PURPOSE: This study was performed to compare clinical outcomes of immediate occlusal versus non-occlusal loading of posterior implants. MATERIALS AND METHODS: Of 19 patients with 52 screw-type implants replacing mandibular molars or premolars, nine patients with 21 implants were randomized to a study group that received immediate restorations with occlusal loading, whereas 10 patients with 31 implants were randomized to a control group that received provisional restorations without occlusal loading. Occlusal loading was defined as full loading in maximum intercuspidation. Single-tooth or splinted multiunit restorations were incorporated by screw retention or cementation. Marginal bone defects (MBD), implant survival, and implant success were evaluated 12 months after insertion. RESULTS: Both groups revealed similar MBD levels consistent with previous reports. No implants were lost (overall survival: 100%) or found to fail (overall success: 100%). No significant intergroup differences were noted for any of the evaluated parameters. CONCLUSIONS: Immediate restorations in partially edentulous mandibles demonstrated successful clinical and radiographic 12-month results. Larger long-term prospective studies are needed to confirm the final evidence and predictability of immediate functional loading as a standard treatment concept for partially edentulous jaws.

Influence of prosthetic parameters on peri-implant bone resorption in the first year of loading: a multi-factorial analysis.

BACKGROUND: The first year of prosthetic loading is crucial to peri-implant bone levels; however, contributing factors are yet barely understood. PURPOSE: The purpose of the study is to investigate the influence of patient-, implant-, and prosthetic-related parameters on marginal bone resorption in partially edentulous patients within the first year of prosthetic loading. MATERIALS AND METHODS: This retrospective multifactorial analysis involved the following influencing factors: patient gender and age, implant diameter, implant location and neck design, insertion torque, insertion depth, splinted versus single-tooth restorations, crown height space, and crown-to-implant ratio. RESULTS: Mean peri-implant bone resorption around 200 dental implants was 0.98 ± 0.76 mm and significantly correlated to higher implant insertion depth (p < .001), whereas no association to prosthetic parameters could be observed. CONCLUSIONS: Within the limits of the present analysis, it can be concluded that apical implant positioning may constitute a relevant determinant of early peri-implant bone resorption.

Human cadaver study evaluating a new measurement technique for graft volumes after sinus floor elevation.

PURPOSE: Volumetric data can be used as complementary information to characterize grafting materials. The aim of this cadaveric study was to analyze a noncommercial measurement technique based on the novel concept of an "interactive rigid registration algorithm" (IRRA). Parameters analyzed included the reproducibility of IRRA measurements and their reliability in comparison with the established measurement technique of "region growing segmentation thresholding" (RGST). MATERIALS AND METHODS: Three human skulls were used to simulate a total of 18 sinus grafts, using three incremental grafting procedures in each sinus (three skulls ×t wo sinuses × three grafting increments). Radiopaque impression material was used for the simulated grafts, whose volumes were recorded by computed tomography from three different tilt angles. The reproducibility of IRRA measurements and the reliability of volumetric results obtained with both the IRRA and RGST techniques were evaluated by appropriate intraclass correlation coefficient (ICC) and Bland-Altman analysis. RESULTS: ICC greater than 0.9 indicated close to perfect agreement of the results obtained with both methods and good reproducibility of the IRRA measurements. Bland-Altman analysis demonstrated good inter-method and intramethod agreement. CONCLUSIONS: The IRRA measurement technique can be recommended as a noninvasive tool to evaluate graft volumes in human maxillary sinuses.

Three-dimensional accuracy of guided implant placement: indirect assessment of clinical outcomes.

PURPOSE: Precise preoperative implant planning and its exact intraoperative transfer are crucial for successful implant-supported rehabilitation of partially or completely edentulous patients. In the present pilot study, optical laser scanning was used to evaluate deviations between three-dimensional computer-assisted planned and actual implant positions by indirect methods. MATERIAL AND METHODS: Five patients receiving a total of 15 implants were included in this study. The used planning software was SimPlant 12.0 (Materialise Dental, Leuven, Belgium) to visualize the implant positions, and with an appropriate guided surgery protocol (Navigator™, Biomet 3i, Palm Beach Gardens, FL, USA) implant positions were implemented via tooth-supported stereolithografic surgical guides. All implants (Osseotite™, Biomet 3i) were inserted in a flapless approach and immediately provided with prefabricated temporary splinted restorations. Intraoral pickup impressions were taken postoperatively, and the implant positions of the master casts were compared with presurgical casts. Implant replica deviations were evaluated by three-dimensional optical laser scanning providing distances and angulations between implant replicas. RESULTS: Overall, the postsurgical implant replica positions were found to deviate from the positions in the preoperative cast by a mean of 0.46 ± 0.21 mm (range: 0.09-0.85 mm). Positional deviations were 0.27 ± 0.19 mm (range: 0.04-0.60 mm) along the x-axis representing the buccal-lingual directions, 0.15 ± 0.13 mm (range: 0.0-0.34 mm) along the y-axis representing the ventrodorsal direction, and 0.28 ± 0.19 mm (range: 0.02-0.59 mm) along the z-axis representing cranial and apical directions. Rotational deviations amounted to 14.04 ± 11.6° (range: 0.09-36.47°). CONCLUSIONS: The results of this pilot study demonstrate precise transfer of implant replica position by means of simulated guided implant insertion into a preoperative cast and a postoperative cast obtained from impressioning. Further studies are needed to identify appropriate evaluation techniques and mechanisms to increase the transfer precision of three-dimensional planning and guiding systems.

Overdentures in the edentulous mandible supported by implants and retained by a Dolder bar: a 5-year prospective study.

PURPOSE: This prospective study was performed to evaluate the outcomes of XiVE® S plus implants (Dentsply Friadent, Mannheim, Germany) following conventional restoration with bar structures and overdentures in the edentulous mandible. MATERIALS AND METHODS: A total of 39 patients were treated with four interforaminal implants (n = 156) splinted by a Dolder bar. Overdentures were attached to the bars after 3 months of healing. As primary outcome measures, clinical and radiological parameters were evaluated at the time of implant placement (baseline) and once a year (1, 2, 3, 4, 5 years) after functional loading. Secondary outcome measures included (i) primary stability and surgical complications, as well as (ii) Periotest® (Medizintechnik Gulden, Modautal, Germany) values, implant survival, and prosthetic complications at baseline and follow-up. RESULTS: A total of 156 implants were placed. The vast majority (n = 149) were tightened to >30 Ncm, while torques in the range of 20-30 Ncm were obtained in the remaining cases (n = 7). Mean crestal bone levels around the implants were 0.41 mm at baseline and 1.04/1.20/1.34/1.45/1.44 mm after 1/2/3/4/5 years respectively. The mean values of the plaque, calculus, bleeding, and mucosal indices remained low throughout this period. The reported follow-up periods involved one implant loss after 3 months (survival rate: 99.4%) and one implant failure after 4 years (success rate: 98.4%). Prosthetic complications included factures of bars (n = 3) and denture teeth (n = 7). Prosthetic survival was 100%. CONCLUSIONS: Dolder bars to restore oral implants in the edentulous mandible appear to offer a high rate of implant survival, good stability of the peri-implant tissue, and a low rate of prosthetic complications.

Comparison of variable-thread tapered implant designs to a standard tapered implant design after immediate loading. A 3-year multicentre randomised controlled trial.

OBJECTIVES: This randomised, controlled multicentre trial aimed at comparing two versions of a variable-thread dental implant design to a standard tapered dental implant design in cases of immediate functional loading for 36 months after loading. MATERIALS AND METHODS: 177 patients (325 implants) were included at 12 study centres and randomly allocated into one of three treatment groups: NAI (variable-thread design, NobelActive internal connection), NAE (variable-thread design, NobelActive external connection) and, as control, NR (standard tapered design, NobelReplace tapered groovy). Inclusion criteria concerned healed bony implant sites and feasibility for immediate loading. Clinical and radiographic examinations were performed at implant placement and after 3, 6, 12, 24 and 36 months. The outcome measures were marginal bone remodelling (primary outcome), implant survival and success, papilla score, plaque accumulation, and bleeding on probing. RESULTS: 127 patients (NAI: 45, NAE: 41, NR: 41) were followed-up and evaluated after 36 months. No significant differences in cumulative survival rates were seen for the groups (NAI: 95.7%; NAE: 96.3%; NR: 96.6%). In all groups, bone remodelling occurred during the first 3 months, with stable or even increasing bone levels after the initial remodelling period. The bone remodelling from insertion to 36 months for the NAI group (-0.89 ± 1.65 mm) was comparable (P = 0.98) to that of the NR group (-0.85 ± 1.32 mm). The NAE group showed comparable bone remodelling during the first year, with an increase in following years resulting in significantly less overall bone loss (-0.16 ± 1.06 mm) (P = 0.041). Overall improvement in papilla size was observed in all treatment groups. CONCLUSIONS: Over 36 months, the results show stable or improving bone levels for all treatment groups after the initial bone remodelling seen during the first 3 months after placement. The variable- thread implants showed results comparable to those of standard tapered implants in cases of immediate function, and therefore can be considered as a treatment option for immediate loading.

Prevalence, location and morphology of maxillary sinus septa: systematic review and meta-analysis.

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 < 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. CONCLUSIONS: 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.

Immediate rehabilitation of the edentulous mandible with screw type implants: results after up to 10 years of clinical function.

OBJECTIVES: The aim of this prospective case series was to evaluate the results of an immediate loading concept using four Xi VE S plus implants in the edentulous mandible, after a period of up to 10 years of clinical function. MATERIAL AND METHODS: Thirty patients were treated with four implants each placed interforaminally and provisionally restored within 1 week. Radiographic bone levels, condition of the peri-implant mucosa, implant survival and success were recorded annually from implant insertion (baseline) up to 10 years after final restoration. RESULTS: A total of 120 Xi VE S plus implants were placed in the interforaminal region. A significant coronal bone loss of 1.80 mm (SD ± 0.65) was recorded within the first 8 years of function (P < 0.001). Within the next years no further significant increase of bone resorption was observed. The mean values of the plaque, calculus, bleeding and mucosal indices and probing depth remained low throughout this period. All implants were inserted with an insertion torque of more than 32 N cm. Two losses (1.7%) occurred prior to permanent restoration (1 and 3 months post-insertion), resulting in a survival rate of 98.3% over the entire observation period. Four implants were recorded as failures due to excessive bone resorption, resulting in an overall success rate of 95%. CONCLUSIONS: The results of this study indicate that in selected patients immediate restoration of dental implants in the edentulous mandible will achieve a clinically predictable outcome.

Immediate provisional restoration of screw-type implants in the posterior mandible: results after 5 years of clinical function.

OBJECTIVE: The aim of this prospective study was to evaluate the outcome of immediately provisionally restored implants in the posterior mandible after a minimum of 60 months in function. MATERIAL AND METHODS: Twenty-four patients were treated with 40 screw-type implants replacing mandibular molars and premolars. Implants were provisionalized immediately after placement. Radiographic coronal bone levels, implant survival and success were evaluated 12, 24, 36, 48 and 60 months after the final restoration. RESULTS: Measurements of the mean marginal bone levels around immediately loaded implants after 12 months showed a significant bone loss (P<0.001) within the first year after the final restoration. Measurements of coronal bone levels after 24, 36, 48 and 60 months, respectively, showed no further significant increase of bone resorption. Two implants were lost within the first year after the final restoration, resulting in an overall survival rate of 95%; a total of three implants were recorded as failures (two implant losses and one excessive bone resorption above 50%), resulting in an overall success rate of 92.5 after an implant observation period of up to 8 years. CONCLUSION: The present data revealed results comparable to conventionally loaded implants. Careful patient selection in combination with high primary stability seem to be key factors for immediately loaded implants. Larger long-term randomized clinical trials are needed to confirm the final evidence of this protocol as the standard treatment concept for the partially edentulous mandible.

Randomized controlled trial comparing a variable-thread novel tapered and a standard tapered implant: interim one-year results.

STATEMENT OF PROBLEM: A tapered implant with continuously changing threads purported to provide stable tissue support and allow immediate function has been developed. Treatment success and stabilization of supporting tissues over time require documentation. PURPOSE: The purpose of this prospective, randomized, controlled, multicenter study was to evaluate changes in bone level and soft tissue behavior between the novel implant (NobelActive/NA) and a standard tapered implant (NobelReplace Tapered Groovy/NR) with regard to immediate function. MATERIAL AND METHODS: A total of 177 patients randomly allocated to 3 treatment groups (2 different test implant groups: NA Internal (n=117; internal connection) and External (n=82), and 1 standard treatment group, NR (n=126)) received 325 implants. Implants were placed into healed sites, and all but 6 implants were immediately nonocclusally loaded. Clinical and radiographic evaluations of treatment success, crestal bone levels, and soft tissue changes were performed at the time of placement and after 3, 6, and 12 months. Log-Rank test was used to analyze the differences in survival rate. Marginal bone level was compared using the Kruskal-Wallis test and Mann-Whitney U-test (alpha=.05). RESULTS: One-year cumulative survival rates were comparable (96.6% for NA Internal; 96.3% for NA External; 97.6% for NR; P=.852; Log-Rank). Mean (SD) change in bone level was -0.95 mm (1.37) for NA Internal, -0.64 mm (0.97) for NA External, and -0.63 mm (1.18) for NR (P=.589; Kruskal-Wallis). Stable soft tissues and significantly increased papilla scores (P<.001; Wilcoxon signed-rank) were observed for all implant types. CONCLUSIONS: The novel implants showed high survival rates as well as stable bone and soft tissue levels after 1 year, and may be recommended for clinical use, even under immediate function.

Evaluation of three-dimensional changes after sinus floor augmentation with different grafting materials.

OBJECTIVE: The aim of this retrospective investigation was to assess the dimensional stability of different grafting materials after maxillary sinus floor augmentation with computed tomography (CT) scans. MATERIALS AND METHODS: Two postoperative CT scans were available from 16 patients who had undergone maxillary sinus lift procedures. The first scan was made within a few days after the surgical intervention and the second one >6 months later. A total of 25 maxillary sinuses were augmented with different materials before implant insertion by lateral antrostomy in a staged approach. The volume of bone formation was calculated using the Somaris Sienet Magic View software. RESULTS: Based on volumetric measurements of the augmented domes derived from the image sections, shrinkage was about 26%. The mean of the augmented bone volume was 3.02 cm(3) (1.4-5.56 cm(3); SD+/-1.18 cm(3)) as determined in the first CT scan. The respective mean volume in the second CT scan amounted to 2.28 cm(3) (0.92-4.46 cm(3); SD+/-1.07 cm(3)). CONCLUSION: Within the limits of our descriptive and analytic study, the results indicate a significant reduction of the graft volume after maxillary sinus augmentation. Further prospective studies will have to evaluate the quantitative changes of different bone graft materials for maxillary sinus augmentation procedures in order to improve long-term implant stability.

Surgical factors influencing mesiodistal implant angulation.

OBJECTIVES: The aim of this experimental study was to identify relevant surgical parameters influencing the mesiodistal angular deviation of dental implants. MATERIAL AND METHODS: Pilot drillings of 2 mm diameter were performed in bovine ribs with a parallelometer. The subsequent preparation of the implant socket was performed freehand. Utilizing six different implant systems, at least 80 drillings per system of different diameters were performed. The pilot drillings were marked with 2 mm steel pins and cephalometric radiographs were taken. The mesiodistal angle between the longitudinal implant axis and the marked pilot drillings was measured and evaluated by a blinded investigator. To evaluate the influence of the surgeons' experience, their drillings were compared with those of a group of unexperienced surgeons. Additionally, the influence of drilling speed and size of bur steps on drilling accuracy were evaluated. RESULTS: The difference between the lowest value of 0.91 degrees of mesiodistal angular deviation found for 3i implants and the highest of 1.36 degrees for Ankylos implants was of low statistical significance (P=0.065). Drillings of experienced surgeons showed less deviation compared with those of a beginners group (P<0.0001). Higher deviations were measured when a bur size was skipped. Drillings performed at high speed showed significantly higher deviations than those with fewer rewinds per minute. CONCLUSION: In order to achieve precise implant angulation, all bur diameters available should be used. Utilizing low drilling speeds results in less mesiodistal deviation. The surgeon's experience seems to be the most relevant factor in precise implant placement.

Immediate provisional restoration of XiVE screw-type implants in the posterior mandible.

OBJECTIVES: This prospective study evaluated the clinical outcome of immediately restored screw-type implants for the replacement of mandibular (pre)molars. The results were based on survival, clinical stability and on changes of bone levels from implant placement to delivery of the definitive superstructure 6 months after insertion. MATERIAL AND METHODS: In this study, 24 patients were treated according to an immediate loading protocol. Forty XiVE implants were placed in the mandibular (pre)molar regions for single-tooth restoration and the treatment of free-end situations. Radiographic bone levels in relation to implant margins were measured at the time of insertion and recorded. All implants were provided with a transfer coping and restored with provisional crowns within 7 days. After 6 months, the final restorations were fabricated. At this time, survival, Periotest value and radiographic bone levels were assessed. RESULTS: A total of 40 XiVE implants were placed with an insertion torque value of at least 45 N cm. The median Periotest value 6 months post-insertion was -5 (maximum -2, minimum -7). The mean radiographic coronal bone level at prosthetic delivery was 1.4 mm (SD+/-0.57) compared with 0.47 mm (SD+/-0.37) at the time of insertion. No implant failures were observed up to prosthetic restoration 6 months post-insertion. CONCLUSION: The present data of immediately loaded implants in the posterior mandible are comparable to results with conventional loaded implants. Additional long-term data will be necessary to include this protocol as a standard procedure in our treatment concepts for the edentulous posterior mandible.

Harvesting of cancellous bone from the proximal tibia under local anesthesia: donor site morbidity and patient experience.

PURPOSE: The objective of this retrospective study was to evaluate postoperative morbidity, risk of complications, and patient discomfort after ambulatory tibial bone harvesting procedures under local anesthesia. PATIENTS AND METHODS: Between 2000 and 2005, bone was harvested from the head of the tibia for internal or external maxillary augmentation in 79 patients. A medial osteoplastic approach to the donor region was used. All patients' records were reviewed. Forty-five of the 79 patients later came in for follow-up examination. A traumatologist examined the donor region both clinically and radiologically. Subjective disorders and experiences of the patients were documented using a standardized questionnaire. RESULTS: The patient records revealed that 80% did not report significant complaints or gait disturbances after bone harvesting, and only 5% reported postoperative complaints or gait disturbances lasting longer than 2 weeks. In 1 case, a nondisplaced fracture healed without further complications. Clinical and radiologic examinations of 45 patients revealed full regeneration of the donor region in all cases. Some 91% of the patients described the outpatient bone harvesting procedure under local anesthesia as "not distressing" and would undergo such an intervention again if required. CONCLUSIONS: This study demonstrates that both complaints and risk of complications after outpatient bone harvesting from the proximal tibia under local anesthesia can be considered very low, especially as far as outpatient maxillary augmentation (eg, sinus floor elevation) is concerned.