Oral implants placed in bone defects treated with Bio‐Oss®, Ostim®‐Paste or PerioGlas: an experimental study in the rabbit tibiae

Objectives: To compare the histological features of bone filled with Bio‐Oss^®, Ostim‐Paste^® or PerioGlas placed in defects in the rabbit tibiae by evaluating bone tissue composition and the integration of titanium implants placed in the grafted bone. Material and methods: Two cylindrical bone defects, about 4 mm in diameter and 6 mm in depth, were created in the tibiae of 10 rabbits. The defects were filled with either Bio‐Oss^®, PerioGlas, Ostim^®‐Paste or left untreated, and covered with a collagen membrane. Six weeks later, one titanium sandblasted and acid‐etched (SLA) implant was inserted at the centre of each previously created defect. The animals were sacrificed after 6 weeks of healing. Results: Implants placed in bone previously grafted with Bio‐Oss^®, PerioGlas or Ostim^®‐Paste obtained a larger extent of osseointegration, although not statistically significant, than implants placed in non‐grafted bone. The three grafting materials seemed to perform in a similar way concerning their contribution towards implant osseointegration. All grafting materials appeared to be osteoconductive, thus leading to the formation of bridges of mineralized bone extending from the cortical plate towards the implants surface through the graft scaffold. Conclusions: Grafting with the above‐mentioned biomaterials did not add any advantage to the osseointegration of titanium SLA implants in a self‐contained defect.     

Long‐Term Follow‐Up on Soft and Hard Tissue Levels Following Guided Bone Regeneration Treatment in Combination with a Xenogeneic Filling Material: A 5‐Year Prospective Clinical Study

Purpose: In the present prospective study, bone augmentation by guided bone regeneration (GBR) in combination with bovine hydroxyapatite (BHA) as filling material was evaluated with regard to soft and hard tissue stability over time. Materials and Methods: Implant survival, radiologic bone level (marginal bone level [MBL]), and clinical soft tissue parameters (marginal soft tissue level [MSTL]) were observed. Twenty patients received a total of 41 implants (Brånemark System, Nobel Biocare, Göteborg, Sweden) in conjunction with GBR treatment. The end point of the study was after 5 years following implant placement. Results: The cumulative implant survival rate was 97.5% corresponding to one implant failure. The radiologic evaluation of the MBL demonstrated a crestal bone height above the level of the fixture head. The bone height decreased from ?3.51 to ?2.38 mm (p < .001). The MSTL was ?1.52 mm at baseline and ?1.15 mm at the 5‐year follow‐up (p < .04) demonstrating a stable submucosal crown margin throughout the study period. Conclusion: GBR treatment in combination with a xenogeneic filling material (BHA) is a viable treatment option in order to maintain stable hard and soft tissue levels in conjunction with augmentative procedure related to oral implant treatment.     

A Prospective 1‐Year Clinical and Radiographic Study of Implants Placed after Maxillary Sinus Floor Augmentation with Synthetic Biphasic Calcium Phosphate or Deproteinized Bovine Bone

Background: The technique of using bone grafts or different biomaterials for augmentation of the maxillary sinus prior to implant placement is well accepted by clinicians. However, clinical documentation of some bone substitutes is still lacking. Purpose: This prospective study was designed to evaluate the success rate of implants placed after maxillary sinus augmentation with a novel synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB), the latter acting as control. Material and Methods: Nine edentulous patients and two partially edentulous patients with a mean age of 67 years with a bilateral need for sinus augmentation, <5 mm residual bone in the floor of the sinus and a crestal width ≥4 mm, were included in the study. After bilateral elevation of the Schneiderian membrane, all patients were randomized for augmentation with synthetic BCP in one side and DBB in the contralateral side. After 8 months of graft healing, 62 implants with an SLActive surface were placed. Implant survival, graft resorption, plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth, and implant success rate were evaluated after 1 year of functional loading. Results: After a mean of 118 days, all patients received their fixed prosthetic constructions. One implant was lost in each biomaterial, giving an overall survival rate of 96.8%. Success rates for implants placed in BCP and DBB were 91.7 and 95.7%, respectively. No significant difference in marginal bone loss was found around implants placed in BCP, DBB, or residual bone, respectively. The mean graft resorption was 0.43 mm (BCP) and 0.29 mm (DBB). Conclusion: In this limited study, implant success rate was not dependent on the biomaterial used for maxillary sinus augmentation. Similar results were found after 1 year of functional loading for implants placed after sinus augmentation using BCP or DBB.     

Long‐Term Follow‐Up of CeraOne™ Single‐Implant Restorations: An 18‐Year Follow‐Up Study Based on a Prospective Patient Cohort

Background: Knowledge on long‐term clinical performance of more than 5 years on the single‐implant CeraOne? (Nobel Biocare AB, Gothenburg, Sweden) concept is limited. Purpose: The aim of this study is to report the long‐term clinical performance of the first CeraOne single‐implant restorations, installed 17 to 19 years ago. Materials and Methods: The group comprised 57 patients provided with 65 CeraOne single‐tooth restorations. Sixty‐two all‐ceramic and three metal‐ceramic crowns were cemented between 1989 and 1991. Patients were followed up clinically and with intraoral radiographs at placement, after 1, 5, and between 17 and 19 years after placement. Results: Data were available for altogether 48 patients, followed up on an average time of 18 years. Excluding deceased patients (n = 2) and failed implant patients (n = 2), only five patients were lost to follow‐up (8.8%). Two implants failed, resulting in an 18‐year implant cumulative success rate (CSR) of 96.8%, and altogether eight original single‐crown restorations were replaced (CSR 83.8%). The most common reason for crown replacement was infra‐position of the implant crown (n = 3). Many of the remaining original crowns showed various signs of implant crown infraposition at the termination of the study. In general, the soft tissue at the restorations was assessed to be healthy and comparable with the gingiva at the adjacent natural teeth. Bone levels were on an average stable with only few patients exhibiting bone loss of more than 2 mm during 18 years in function. Conclusion: This long‐term follow‐up study of single‐implant restorations shows encouraging results with few implant failures and minimal bone loss over an 18‐year period. Original single‐crown restorations were replaced more frequently, because of, for example, implant crown infraposition and veneer fractures. The CeraOne concept proved to be a highly predictable and safe prosthodontic treatment.     

Clinical and radiographic characteristics of single‐tooth replacements preceded by local ridge augmentation: a prospective randomized clinical trial

Objectives: To assess in a randomized‐clinical trial the influence of three augmentation techniques (chinbone with or without a Bio‐Gide^® membrane and Bio‐Oss^® with a Bio‐Gide^® membrane) on the clinical and radiographic characteristics of hard and soft tissues around implants and adjacent teeth in the reconstructed maxillary anterior region, up to 1 year after functional loading. Materials and methods: Ninety‐three patients requesting single‐tooth replacement and presenting with a horizontal (bucco‐palatinal) bone deficiency were included. After augmentation, 93 ITI‐Esthetic^Plus implants were placed. Clinical variables, standardized photographs and radiographs were analysed to assess the impact on the levels of the marginal gingiva (MGL) and marginal bone (MBL) around implants and adjacent teeth, viz at pre‐augmentation, pre‐implantation (TPI) and 1 (T₁) and 12 (T₁₂) months after final crown placement. Results: Implant survival was 97.8%. No significant differences were observed in the treatment outcomes of the three augmentation modalities. Combining the three modalities, a slight but significant increase in the implants approximal pocket depth was found between T₁ and T₁₂. Approximal bone loss at the implant between T₁ and T₁₂ was 0.14 ± 0.76 mm (mesial) and 0.14 ± 0.47 mm (distal); the approximal MGL slightly increased (mesial: 0.24 ± 0.46 mm, distal: 0.25 ± 0.66 mm), and the buccal MGL decreased (0.11 ± 0.61 mm). Bone loss at the adjacent teeth, although minor, was significant between TPI and T₁. No correlations were observed in changes of MBL and MGL. Conclusions: None of the three applied augmentation technique procedures influenced the characteristics of the MGL and MBL or the implant survival of single‐tooth replacements. Peri‐implant hard and soft tissues were very stable in the first year after loading.     

Long‐term results after lateral and osteotome technique sinus floor elevation: a retrospective analysis of 2190 implants over a time period of 15 years

Background: During a time period of 15 years (1992–2007), 2190 implants were inserted in 983 patients after sinus floor elevation. Materials and methods: One thousand two hundred and seven implants (461 patients) were placed into sites, in which the sinus was augmented using the lateral approach (LSFE), and 983 implants (522 patients) in sites augmented with the osteotome technique. Bovine bone mineral (n=1217), β‐tricalcium phosphate (n=126), and in some cases, only autogenous bone were used for augmentation in the LSFE. Generally, bone chips that were collected during the preparation of the osteotomy were added to the bone substitutes. No additional augmentation materials were used for augmentation with the osteotome technique. A retrospective analysis of the treatment results was assessed by patients documentations that were recorded in the impDAT(R) – Program and by the evaluation of pre‐, and post‐surgical orthopantomograms. Results: The implant survival analysis according to Kaplan–Meier showed 97.1% after 176 months of loading for both sinus floor elevation techniques. Discussion and conclusion: The evaluation with respect to the augmentation material used did not reveal significant differences in the implant survival rate and in both cases remodelling processes could be observed in the augmented area. To cite this article:
Tetsch J, Tetsch P, Lysek DA. Long‐term results after lateral and osteotome technique sinus floor elevation: a retrospective analysis of 2190 implants over a time period of 15 years.
Clin. Oral Impl. Res. 21 , 2010; 497–503.
doi: 10.1111/j.1600‐0501.2008.01661.x     

Prospective Evaluation of 2,549 Morse Taper Connection Implants: 1‐ to 6‐Year Data

Background: The aim of this study is to evaluate the implant survival, the implant–crown success, and the prosthetic complications of 2,549 Morse taper interference–fit connection implants. Methods: A total of 2,549 Morse taper connection implants were inserted in 893 patients from January 2003 until December 2008. At each annual recall, clinical, radiographic, and prosthetic parameters were assessed. The implant–crown success criteria included the absence of pain, suppuration, and clinical mobility; an average distance between the implant shoulder and the first visible bone contact <2 mm from initial surgery; and the absence of prosthetic complications at the implant–abutment interface. Prosthetic restorations were fixed partial prostheses (462 units); fixed full‐arch prostheses (60 units); single crowns (531 units); and overdentures (93 units). Results: The cumulative implant survival rate was 98.23% (97.25% maxilla, 99.05% mandible). The implant–crown success was 92.49%. A few prosthetic complications at implant–abutment interface were reported (0.37%). After 6 years, distance between the implant shoulder and the first visible bone contact was 1.10 mm (± 0.30 mm). Conclusion: The use of Morse taper connection implants represents a successful procedure for the rehabilitation of partially and completely edentulous arches.     

A 10‐year retrospective analysis of radiographic bone‐level changes of implants supporting single‐unit crowns in periodontally compromised vs. periodontally healthy patients

Aim: To compare the 10‐year peri‐implant bone loss (BL) rate in periodontally compromised (PCP) and periodontally healthy patients (PHP) around two different implant systems supporting single‐unit crowns. Materials and methods: In this retrospective, controlled study, the mean BL (mBL) rate around dental implants placed in four groups of 20 non‐smokers was evaluated after a follow‐up of 10 years. Two groups of patients treated for periodontitis (PCP) and two groups of PHP were created. For each category (PCP and PHP), two different types of implant had been selected. The mBL was calculated by subtracting the radiographic bone levels at the time of crown cementation from the bone levels at the 10‐year follow‐up. Results: The mean age, mean full‐mouth plaque and full‐mouth bleeding scores and implant location were similar between the four groups. Implant survival rates ranged between 85% and 95%, without statistically significant differences (P>0.05) between groups. For both implant systems, PCP showed statistically significantly higher mBL rates and number of sites with BL≥3 mm compared with PHP (P<0.0001). Conclusions: After 10 years, implants in PCP yielded lower survival rates and higher mean marginal BL rates compared with those of implants placed in PHP. These results were independent of the implant system used or the healing modality applied. To cite this article:
Matarasso S, Rasperini G, Iorio Siciliano V, Salvi GE, Lang NP, Aglietta M. A 10‐year retrospective analysis of radiographic bone‐level changes of implants supporting single‐unit crowns in periodontally compromised vs. periodontally healthy patients.
Clin. Oral Impl. Res. 21 , 2010; 898–903.
doi: 10.1111/j.1600‐0501.2010.01945.x     

Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study

Aim: To evaluate prospectively the clinical and radiographic outcomes after 2 years of loading of 6 mm long moderately rough implants supporting single crowns in the posterior regions. Material and methods: Forty SLActive Straumann^® short (6 mm) implants were placed in 35 consecutively treated patients. Nineteen implants, 4.1 mm in diameter, and 21 implants, 4.8 mm in diameter, were installed. Implants were loaded after 6 weeks of healing. Implant survival rate, marginal bone loss and resonance frequency analysis (RFA) were evaluated at different intervals. The clinical crown/implant ratio was also calculated. Results: Two out of 40 implants were lost before loading. Hence, the survival rate before loading was 95%. No further technical or biological complications were encountered during the 2‐year follow‐up. The mean marginal bone loss before loading was 0.34±0.38 mm. After loading, the mean marginal bone loss was 0.23±0.33 and 0.21±0.39 mm at the 1‐ and 2‐year follow‐ups. The RFA values increased between insertion (70.2±9) and the 6‐week evaluation (74.8±6.1). The clinical crown/implant ratio increased with time from 1.5 at the delivery of the prosthesis to 1.8 after 2 years of loading. Conclusion: Short implants (6 mm) with a moderately rough surface loaded early (after 6 weeks) during healing yielded high implant survival rates and moderate loss of bone after 2 years of loading. Longer observation periods are needed to draw more definite conclusions on the reliability of short implants supporting single crowns. To cite this article:
Rossi F, Ricci E, Marchetti C, Lang NP, Botticelli D. Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study.
Clin. Oral Impl. Res. 21 , 2010; 937–943.
doi: 10.1111/j.1600‐0501.2010.01942.x     

Accuracy of measuring the cortical bone thickness adjacent to dental implants using cone beam computed tomography

Objective: To assess the accuracy of measuring the cortical bone thickness adjacent to dental implants using two cone beam computed tomography (CBCT) systems. Material and methods: Ten 4 × 11 mm Astra Tech^® implants were placed at varying distances from the cortical bone in two prepared bovine ribs. Both ribs were scanned in a reproducible position using two different CBCT scanners. Ten examiners each carried out four measurements on all 10 implants using the two CBCT systems: vertical distance between the top of the implant and the alveolar crest (IT–AC), and thickness of the cortical bone from the outer surface of the implant threads at 3, 6 and 9 mm from the top of the implant. Ground sections were prepared and bone thickness was measured using a light microscope and a graticule to give a gold standard (GS) measurement. Results: The examiner's measurements were significantly different between CBCT systems for the vertical and thickness dimensions (P<0.001) while measuring the cortical bone thickness between 0.3 and 3.7 mm. Within that range, i‐CAT NG^® measurements were consistently underestimated in comparison with the GS. Accuitomo 3D60 FPD^® measurements closely approximated the GS, except when cortical bone thickness was <0.8 mm. The mean percentage errors from the GS at 3, 6 and 9 mm measurement levels were 68%, 28% and 18%, respectively, for i‐CAT NG^® and 23%, 5% and 6%, respectively, for Accuitomo 3D60 FPD^®. Conclusions: Within the limitations of this study, it was concluded that i‐CAT NG^® (voxel size 0.3) may not produce sufficient resolution of the thin cortical bone adjacent to dental implants and, therefore, the measurements may not be accurate; whereas, Accuitomo 3D60 FPD^® (voxel size 0.125) may produce better resolution and more accurate measurement of the thin bone. To cite this article: Razavi T, Palmer RM, Davies J, Wilson R, Palmer PJ. Accuracy of measuring the cortical bone thickness adjacent to dental implants using cone beam computed tomography. Clin. Oral Impl. Res. 21 , 2010; 718–725.
doi: 10.1111/j.1600‐0501.2009.01905.x     

Efficacy of Cancellous Block Allograft Augmentation Prior to Implant Placement in the Posterior Atrophic Mandible

Background: The present study evaluated the outcome of ridge augmentation with cancellous freeze‐dried block bone allografts in the posterior atrophic mandible followed by placement of dental implants. Materials and Methods: A bony deficiency of at least 3 mm, horizontally, vertically, or both, according to computerized tomography (CT) para‐axial reconstruction served as inclusion criteria. Implants were inserted after a healing period of 6 months. Bone measurements were taken prior to bone augmentation, during implant placement, and at second‐stage surgery. Marginal bone loss and crown‐to‐implant ratio were also measured. Results: Twenty‐nine cancellous allogeneic bone blocks were placed in 21 patients. The mean follow‐up was 37 months. Bone block survival rate was 79.3%. Mean horizontal and vertical bone gains were 5.6 and 4.3 mm, respectively. Mean buccal bone resorption was 0.5 mm at implant placement and 0.2 mm at second‐stage surgery. A total of 85 implants were placed. Mean bone thickness buccal to the implant neck was 2.5 mm at implant placement and 2.3 mm at second‐stage surgery. There was no evidence of vertical bone loss between implant placement and second‐stage surgery. Implant survival rate was 95.3%. All patients received a fixed implant‐supported prosthesis. At the last follow‐up, the mean marginal bone loss was 0.5 mm. The mean crown‐to‐implant ratio was 0.96. Conclusion: Implant placement in the posterior atrophic mandible following augmentation with cancellous freeze‐dried bone block allografts may be regarded as a viable treatment alternative.     

A 10‐year retrospective analysis of marginal bone‐level changes around implants in periodontally healthy and periodontally compromised tobacco smokers

Aim: To compare the 10‐year marginal bone loss rates around implants supporting single‐unit crowns in tobacco smokers with and without a history of treated periodontitis. Materials and methods: In this retrospective controlled study, 40 tobacco smokers were divided into four groups of 10 patients each. Two groups of periodontally compromised (PC) patients and two groups of periodontally healthy (PH) patients were established. PC patients had been treated for their periodontal conditions before implant placement. All patients were enrolled in a regular, individually tailored maintenance care program. For the rehabilitation of PC and PH patients, two different types of implants were used (Nobel Biocare AB; Straumann^® Dental Implant System). The radiographic bone loss rate was calculated by subtracting the bone levels at the time of crown delivery from the bone levels at the 10‐year follow‐up. Results: The mean age, mean full‐mouth plaque score and full‐mouth bleeding score and implant location were similar for the four groups. Implant survival rates ranged between 70% and 100%, without statistically significant differences between the four groups (P>0.05). Implants placed in PC patients yielded statistically significantly higher marginal bone loss rates compared with those in PH patients (P<0.05), independent of the implant system used. Conclusion: After 10 years, implants placed in tobacco smokers with a history of treated periodontitis and enrolled in a supportive therapy program yielded lower survival rates and higher marginal bone loss rates compared with those of implants placed in PH smokers. These outcomes were independent of the implant system installed or the healing modality applied. To cite this article:
Aglietta M, Iorio Siciliano V, Rasperini G, Cafiero C, Lang NP, Salvi GE. A 10‐year retrospective analysis of marginal bone‐level changes around implants in periodontally healthy and periodontally compromised tobacco smokers
Clin. Oral Impl. Res. 22 , 2011; 47–53.
doi: 10.1111/j.1600‐0501.2010.01977.x     

Crestal Bone Changes at Teeth and Implants in Periodontally Healthy and Periodontally Compromised Patients. A 10‐Year Comparative Case‐Series Study

Background: Limited data exist on the longitudinal crestal bone changes around teeth compared with implants in partially edentulous patients. This study sought to compare the 10‐year radiographic crestal bone changes (bone level [BL]) around teeth and implants in periodontally compromised (PCPs) and periodontally healthy (PHPs) patients. Methods: A total of 120 patients were evaluated for the radiographic crestal BL around dental implants and adjacent teeth at time of implant crown insertion and at the 10‐year follow‐up. Sixty patients had a previous history of periodontitis (PCPs), and the remaining 60 were PHPs. In each category (PCP and PHP), two different implant systems were used. The mean BL change at the implant and at the adjacent tooth at the interproximal area was calculated by subtracting the radiographic crestal BL at the time of crown cementation from the radiographic crestal BL at the 10‐year follow‐up. Results: At 10 years after therapy, the survival rate ranged from 80% to 95% for subgroups for implants, whereas it was 100% for the adjacent teeth. In all eight different patient categories evaluated, teeth demonstrated a significantly more stable radiographic BL compared with adjacent dental implants (teeth BL, 0.44 ± 0.23 mm; implant BL, 2.28 ± 0.72 mm; P <0.05). Radiographic BL changes around teeth seemed not to be influenced by the presence or absence of advanced bone loss (≥3 mm) at the adjacent implants. Conclusions: Natural teeth yielded better long‐term results with respect to survival rate and marginal BL changes compared with dental implants. Moreover, these findings also extend to teeth with an initial reduced periodontal attachment level, provided adequate periodontal treatment and maintenance are performed. As a consequence, the decision of tooth extraction attributable to periodontal reasons in favor of a dental implant should be carefully considered in partially edentulous patients.     

Implant treatment in combination with lateral augmentation of the alveolar process: a 3-year prospective study

Background: In patients in whom the height of the alveolar process is adequate but the crest is too narrow to host an implant, lateral augmentation is required. Such augmentations have mostly been performed using autogenous bone blocks secured to the buccal surface. An alternative to autogenous bone may be bovine hydroxyapatite (Bio‐Oss, Geistlich Pharma AG, Wolhusen, Switzerland) or other bone substitutes. Purpose: The aim of this study was to evaluate the clinical and radiographic outcome of dental implants inserted after lateral augmentation of too narrow alveolar processes with a combination of bovine hydroxyapatite (Bio‐Oss) and autogenous bone. Methods: Thirty patients (14 males and 16 females) with a mean age of 41.6 years fulfilled the inclusion criteria. Twenty‐nine augmentation sites with a total of 74 implants could be followed for 3 years. Results: Three implants were lost; these were lost before loading (at the abutment operation). The survival rate was 95.9%. The mean marginal bone loss during the 3‐year observation period was 0.3 ± 0.2 mm. Conclusions: A 50/50 combination of Bio‐Oss and autogenous bone chips stabilized with Tisseel (Baxter AG/Duo Quick AG, Vienna, Austria) was useful for lateral augmentation of the alveolar crest. Lateral grafts with Bio‐Oss, autogenous bone, and Tisseel made it possible to achieve good implant stability and high implant survival results. The bone level changes adjacent to the implants were the same as in nongrafted cases.     

The Digital One‐Abutment/One‐Time Concept. A Clinical Report

The digital fabrication of dental restorations on implants has become a standard procedure during the last decade. Avoiding changing abutments during prosthetic treatment has been shown to be superior to the traditional protocol. The presented concept for implant‐supported single crowns describes a digital approach without a physical model from implant placement to final delivery in two appointments. A 54‐year‐old man was provided with a single‐tooth implant on his left mandibular first molar. Before wound closure, the implant position was captured digitally with an intraoral scanning device. After bone healing at the time of second‐stage surgery the final screw‐retained crown fabricated without a physical model was inserted. Soft tissue healing took place at the definitive restoration, avoiding abutment changes or changes of the healing cap. These led to stable soft tissues with a minimum of surgery. The benefits of digital fabrication and the unique way to scan the implant right after placement give an additional value that would not be achieved by analog techniques. In addition to financial benefits it represents a biologically advantageous, one‐abutment/one‐time approach with customized screw‐retained, full‐contour crowns or cemented crowns on custom abutments.     

Volumetric changes of the graft after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios: a radiographic study in minipigs

Objective: The objective of the present study was to learn about the volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone from the iliac crest or the mandible in different ratios in minipigs. Material and methods: Bilateral maxillary sinus floor augmentation was performed in 40 minipigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio‐Oss, (C) 50% autogenous bone and 50% Bio‐Oss, (D) 25% autogenous bone and 75% Bio‐Oss, and (E) 100% Bio‐Oss. The autogenous bone graft was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with implant placement. Computed tomographies of the maxillary sinuses were obtained preoperatively, immediately postoperatively, and at euthanasia after 12 weeks. The volumetric changes of the graft were estimated using the Cavalieri principle and expressed as mean percentage with a 95% confidence interval (CI). Results: The mean volume of the graft was reduced by (A) 65% (95% CI: 60–70%), (B) 38% (95% CI: 35–41%), (C) 23% (95% CI: 21–25%), (D) 16% (95% CI: 12–21%), and (E) 6% (95% CI: 4–8%). The volumetric reduction was significantly influenced by the ratio of Bio‐Oss and autogenous bone (P<0.001), but not by the origin of the autogenous bone graft (P=0.2). Conclusions: The volume of autogenous bone grafts from the iliac crest and the mandible is reduced significantly after maxillary sinus floor augmentation in minipigs. The graft volume is better preserved after the addition of Bio‐Oss and the volumetric reduction is significantly influenced by the ratio of Bio‐Oss and autogenous bone. However, further studies are needed addressing the amount of new bone formation and bone‐to‐implant contact before the final conclusion can be made about the optimal ratio of Bio‐Oss and autogenous bone. To cite this article:
Jensen T, Schou S, Svendsen PA, Forman JL, Gundersen HJG, Terheyden H, Holmstrup P. Volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone in different ratios: a radiographic study in minipigs.
Clin. Oral Impl. Res. 23 , 2012; 902–910
doi: 10.1111/j.1600‐0501.2011.02245.x     

Healing of Extraction Sockets Filled with BoneCeramic® Prior to Implant Placement: Preliminary Histological Findings

Background: Various grafting materials have been designed to minimize edentulous ridge volume loss following tooth extraction by encouraging new bone formation in healing sockets. BoneCeramic® is a composite of hydroxyapatite and bèta‐tricalcium phosphate with pores of 100–500 microns. Purposes: The aim of this study was to evaluate bone regeneration in healing sockets substituted with BoneCeramic® prior to implant procedures. Materials and Methods: Fifteen extraction sockets were substituted with BoneCeramic® and 14 sockets were left to heal naturally in 10 patients (mean age 59.6 years). Biopsies were collected only from the implant recipient sites during surgery after healing periods ranging from 6–74 weeks (mean 22). In total, 24 biopsies were available; 10 from substituted and 14 from naturally healed sites. In one site, the implant was not placed intentionally and, in four substituted sites, implant placement had to be postponed due to inappropriate healing, hence from five sites biopsies were not available. Histological sections were examined by transmitted light microscope. Results: At the time of implant surgery, bone at substituted sites was softer than in controls, compromising initial implant stability. New bone formation at substituted sites was consistently poorer than in controls, presenting predominantly loose connective tissue and less woven bone. Conclusion: The use of BoneCeramic® as a grafting material in fresh extraction sockets appears to interfere with normal healing processes of the alveolar bone. On the basis of the present preliminary findings, its indication as a material for bone augmentation when implant placement is considered within 6–38 weeks after extraction should be revised.     

Bone alterations at implant‐supported FDPs in relation to inter‐unit distances: a 5‐year radiographic study

Objectives: The aim of this 5‐year study was to longitudinally evaluate bone alterations around implants with a conical implant–abutment interface in relation to implant–tooth and inter–implant distances. Material and methods: The patient sample comprised 43 partially dentate patients with a total of 48 implant‐supported fixed dental prostheses (FDPs) supported by 130 Astra Tech^® implants. Following FDP placement (baseline), the patients were enrolled in an individually designed supportive care program. Radiographic examinations were performed at the time of FDP installation, 1 and 5 years of follow‐up. Variables regarding implant position and proximal bone topography at tooth/implant units (n=36) and implant/implant units (n=67) were assessed with the use of a software program after scanning of the radiographs. Results: At tooth/implant units, the mean 5‐year marginal bone loss at the tooth, the implant and the mid‐proximal bone crest was 0.1, 0.4 and 0.2 mm, respectively. The mean longitudinal bone loss at the implant/implant units was 0.5 mm at the implants and 0.3 mm mid‐proximally. Multilevel regression analysis revealed that at implant/implant units, the change in the bone‐to‐implant contact level was a significant predictor with regard to the 5‐year mid‐proximal bone‐level change, whereas the horizontal inter‐unit distance showed a borderline significance (P=0.052). At tooth/implant units, no statistically significant associations were identified. Conclusions: The results of this 5‐year study revealed differences between inter‐implant and tooth–implant proximal areas with regard to bone crest alterations and associated factors. To cite this article:
Chang M, Wennström JL. Bone alterations at implant‐supported FDPs in relation to inter‐unit distances: a 5‐year radiographic study.
Clin. Oral Impl. Res. 21 , 2010; 735–740.
doi: 10.1111/j.1600‐0501.2009.01893.x     

Implant‐Supported Fixed Dental Prostheses with CAD/CAM‐Fabricated Porcelain Crown and Zirconia‐Based Framework

Recently, fixed dental prostheses (FDPs) with a hybrid structure of CAD/CAM porcelain crowns adhered to a CAD/CAM zirconia framework (PAZ) have been developed. The aim of this report was to describe the clinical application of a newly developed implant‐supported FDP fabrication system, which uses PAZ, and to evaluate the outcome after a maximum application period of 36 months. Implants were placed in three patients with edentulous areas in either the maxilla or mandible. After the implant fixtures had successfully integrated with bone, gold‐platinum alloy or zirconia custom abutments were first fabricated. Zirconia framework wax‐up was performed on the custom abutments, and the CAD/CAM zirconia framework was prepared using the CAD/CAM system. Next, wax‐up was performed on working models for porcelain crown fabrication, and CAD/CAM porcelain crowns were fabricated. The CAD/CAM zirconia frameworks and CAD/CAM porcelain crowns were bonded using adhesive resin cement, and the PAZ was cemented. Cementation of the implant superstructure improved the esthetics and masticatory efficiency in all patients. No undesirable outcomes, such as superstructure chipping, stomatognathic dysfunction, or periimplant bone resorption, were observed in any of the patients. PAZ may be a potential solution for ceramic‐related clinical problems such as chipping and fracture and associated complicated repair procedures in implant‐supported FDPs.     

A 10‐Year Prospective Study of Single Tooth Implants Placed in the Anterior Maxilla

Purpose: The aim of the study was to evaluate the biological and technical outcomes of early and delayed placed single tooth implants after 10 years of follow‐up. Materials and Methods: Twenty consecutive patients who needed a single tooth replacement in the anterior maxilla were included in this study. Ten implants were placed with an early placement protocol, that is, 4 weeks after tooth extraction, whereas the other 10 implants were placed with a conventional delayed placement protocol, for example, 12 weeks after tooth extraction. At the baseline and at the annual re‐examinations, pain from implant regions, mobility, plaque, mucositis, and marginal bone levels were recorded. Biological and technical complications were registered. The patients evaluated the functional and aesthetic outcomes subjectively on a visual analogue scale after 3 and 10 years. Results: All implants were still in situ after 10 years. The cumulative implant survival rate was 100%. Two implant‐supported crowns were remade because of ceramic fractures. The 10‐year crown survival rate was 90%. No significant differences in implant survival rates were found between the early and delayed protocols, regarding plaque retention, mucositis, or marginal bone levels. After 10 years, the mean marginal bone loss at both sides of the implants was less than 1.0 mm in the two groups. During the 10‐year interval, 1 patient lost more than 1.5 mm of marginal bone, 3 patients lost between 1.0 mm and 1.4 mm of bone, and 16 patients lost less than 1.0 mm of bone as an average of the mesial and distal bone loss. Conclusions: This 10‐year prospective clinical trial demonstrated a 100% implant survival and a 90% crown survival. The average marginal bone level change was less than 1 mm, and there was no difference between early and delayed implant placement. Patient satisfaction with the implant‐supported single crowns reduced with time.