Objectives
The purpose of this study was to determine the existence of correlations between marginal peri-implant linear bone loss and the angulation of implants in maxillary and mandibular augmented ...areas over the course of a 2-year survey.
Materials and methods
Dependent variables described the sample of the present retrospective chart review. By using three-dimensional radiographs, input variables, describing the implant angulation (buccal–lingual angle
φ
and mesial–distal angle
θ
) were measured; outcome variables described survival rate and marginal bone resorption (MBR) around dental implants in autogenous grafts (10 maxillae and 14 mandibles). Pairwise comparisons and linear correlation coefficient were computed.
Results
The peri-implant MBR in maxillary buccal and palatal areas appeared less intensive in the presence of an increased angulation of an implant towards the palatal side. Minor MBR was recorded around mandibular dental implants positioned at a right angle and slightly angulated towards the mesial.
Conclusions
Resorption in buccal areas may be less intensive as the angulation of placed implants increases towards the palatal area in the maxilla, whereas for the mandible, a greater inclination towards the lingual area could be negative. In the mandibular group, when the implant was slightly angulated in the direction of the distal area, bone resorption seemed to be more marked in the buccal area.
Clinical relevance
In the planning of dental implant placement in reconstructed alveolar bone with autograft, the extremely unfavourable resorption at the buccal aspect should be considered; this marginal bone loss seemed to be very sensitive to the angulation of the dental implant.
Purpose To evaluate associations between the osseous remodeling and the 3-dimensional features of both the grafted bone and the recipient site, as well as the density of the grafted bone, and to ...assess the relation between the degree of bone resorption and the type of autogenous bone-grafting procedure or the source (block or particulate bone from iliac crest or block bone from chin). Patients and Methods A retrospective chart review of patients receiving sinus lifting and grafting procedures for implant positioning was conducted: radiographic analysis of the volume and area of both sinuses and autogenous bone grafts was performed, as per Smolka et al and Krennmair et al. The volumetric remodeling—measured at 1 year after implant positioning as the percentage of residual bone (%R)—was correlated, with Spearman analysis, to 3-dimensional features of both graft and recipient sites. All quantities correlated with %R at a statistically significant level were used for 2-dimensional and multidimensional visualizations with scattergrams. Results Twenty-five iliac crest or chin grafts were inlay positioned in the maxillary sinuses of patients. Computed tomography scans, taken before implant positioning and after 1 year, showed a 1-year negligible volume remodeling for block graft from chin (97.9%) but slightly greater resorption values (%R) for particulate and block grafts from iliac crest (93.8% and 83.3%, respectively). Three- and four-dimensional scattergrams of significant data resulting from Spearman correlation tests (particulate and block grafts both from iliac crest) showed a variation of the remodeling pattern dependent on 3-dimensional features, namely inlay graft thickness, surface area of the graft in contact with basal bone, volume of the recipient site, and surface area of the graft projecting into the sinus cavity. Conclusions Retrospective data analysis shows that iliac crest grafts positioned on a small basal bone volume (≤2.5 mL) may point to a very favorable remodeling of the volume when the particulate graft is molded to a thickness of less than 4 mm, with a reduced surface area protruding into the sinus (≤5 cm2 ). Bone blocks with a reduced contact surface and with basal bone (≤4 cm2 ) also display minimal resorption.
Objectives
The aim of the study was to analyze volume changes of post‐extractive sockets grafted with or without deproteinized bovine bone mineral (DBBM) and a resorbable barrier.
Materials and ...methods
This retrospective analysis utilized patients who had undergone tooth extraction. Sites, one per patient, were allocated to two groups: post‐extractive non‐grafted sockets (NG) and post‐extractive grafted sockets with DBBM and resorbable barrier insertion (G). Maximal primary soft tissue closure was sought for both procedures. Before extraction and 6 months later, three‐dimensional features of the sockets (linear indexes, areas, and volumes) and outcome variables at 6 months (volume‐ and surface changes) were acquired through computer tomography scans. Intra‐ and inter‐group comparisons of the outcome variables were performed. Nonparametric tests were applied with a level of significance set at P < 0.01.
Results
Twenty‐four sites, 9 grafted and 15 ungrafted, were enrolled. Between baseline and the 6‐month evaluation, significant bone volume loss, superior surface shrinkage, and height reduction were registered for the G (72 mm3, 76 mm2, and 0.5 mm, respectively) and the NG group (274 mm3, 87 mm2, and 1.8 mm, respectively) with all P‐values ≤ 0.0039. A significant difference, regarding the percentage of the volume change, was registered between the two procedures with a volume loss of 9.9% for the grafted sockets and 34.8% for the ungrafted ones (P‐value = 0.0073).
Conclusion
Grafting of the sockets with DBBM and a resorbable barrier insertion seemed to reduce negative osseous remodeling in the short term when compared to that of the ungrafted sockets.
Abstract Objectives To compare volumetric bone changes after sinus augmentation for implant positioning using blocks of autogenous iliac bone or freeze-dried allogeneic bone (FDBA) from the hip. ...Variables were compared between the two sources and for each surgical procedure at set times (pre- and post-augmentation procedure). Patients and methods A non-randomized retrospective chart review of 7 patients who had autogenous and 7 allogeneic block grafts was carried out (1 procedure per patient). Analysis of Computer Tomographic (CT) data of maxillary sinuses, acquired with high-speed, double-detector CT scanner, was performed using dentascan software. The change between the preoperative ( T0 ) and postoperative volume was measured at 4–6 months ( T2 ) and 1.5 year after transplantation ( T3 ). Annual- and overall-rates of bone change were calculated for the two sources. Results All patients were partially edentulous with a residual maxillary floor thickness in the planned implant insertion sites of 2.7 (0.5) mm and 2.8 (0.5) mm for allogeneic and autogenous procedures respectively. From identical intraoperative volume of grafts (2.25 cc at T1 ), volumetric changes were recorded at T2 and T3 . The final volume of the grafts was 1.44 cc for allogeneic group and 1.78 cc for the autogenous group. Significant volumetric changes over time of transplanted grafts for both sources (23% for autograft and 18% for allograft) were found at T2 . At 1.5-years post-operatively comparisons of volumes and rates of bone loss between sources were not statistically significant. No failure was recorded for either bone grafts or dental implants. Conclusions Short-term sinus grafting procedure for dental implant placement performed with FDBA showed an outcome close to that reported for autogenous bone. Volumetric changes were comparable between the sources. These data suggest that performing maxillary sinus augmentation with dry-preserved bone allogeneic materials in block form could be considered even when the residual floor thickness is less than 3 mm.
Background
Alveolar ridge volume loss may be minimized when postextraction sockets are filled by bone substitutes.
Purpose
The aim of the study was to measure the effect of alveolar ridge ...preservation (ARP) in maintaining the external contour of the ridge after fresh socket grafting with or without particulate anorganic bovine bone mineral (BBM) and resorbable barrier covering.
Materials and methods
In the present controlled study, patients subjected to single‐tooth extraction were allocated to 2 groups: postextraction sockets grafted with bovine bone mineral (bbm), and naturally healing sockets (nat). Before and at 5 months following tooth extraction, plaster cast contours of the sockets were acquired by means of an optical scanner; the 2 contours of each patient underwent voxelization and fusion using a matrix elaborator. Outcome variables at 5 months (volumetric, surface, and linear changes) were measured in digital fused plaster casts with a dental scan software analyzing a volume of interest ranging from residual papilla to 10 mm toward the apical point. Intra‐ and inter‐group pair‐wise variables' comparisons were conducted. Level of significance was set at 0.05.
Results
Twenty‐four sites were enrolled: 12 ARP and 12 naturally healed. Five‐month percentage of volume loss of the bbm‐group (21.7% ± 7.4%) was significantly lower (Ps < .0003) than that of the naturally healing group (38.8% ± 7.9%). When tooth position was investigated, volume loss in percentage registered a significantly better (P values ≤ .0485) behavior in molars (ΔV% = −19.1% ± 6.5% and ΔV% = −35.6% ± 7.6%, respectively, for bbm and nat) than that in premolars (ΔV% = −26.9% ± 7.2% and ΔV% = −45.1% ± 4.2%, respectively, for bbm and nat), in both the preserved and naturally healing groups.
Conclusion
The dimensional loss in postextraction sockets grafted with anorganic bovine bone substitute and covered by a resorbable collagen barrier was lower than that of the naturally healing sites. However, ridge preservation was able to maintain almost 80% of the pristine bone.
Objectives
The present study analysed apical and marginal bone remodelling around dental implants placed in both maxillary (sinus elevated with particulated autogenous osseous graft) and ...corresponding native bone areas, with a follow‐up of 5 years. The clinical survival of implants was also observed.
Materials and methods
In this retrospective chart review, 27 patients were enrolled, with 55 dental implants inserted from 2000 to 2006, 26 of which were followed (one implant per patient); if required, patients were treated via sinus lift with autogenous bone and particulate technique. The internal controls were implants positioned in native areas beneath the sinus. Radiologic survey was assessed via computerized tomographic analysis measuring apical bone level (ABL) and marginal bone level (MBL), at 1‐ (T1), 3‐ (T2) and 5 years (T3), around implants (buccal, b; palatal, p; mesial, m; and distal sides, d). Clinical probing depth (CPD) and clinical attachment level (CAL) for all the four peri‐implant aspects were measured. Cumulative survival rate (CSR) and survival rate (SR) of implants were calculated. Significances for paired and unpaired comparisons were searched for.
Results
A significant degree of apical resorption was recorded between T1 and T3 for the mesial particulate group; again, a significant difference was discovered between the native and particulate procedures for mABL. A further feature was discovered for the particulate procedure, for which ABLs resulted negative at least for three of the aspects. Regarding MBL measurements, similar behaviours were revealed using time‐comparison analysis for the two procedures at the buccal aspect. Comparisons among diameters, irrespective of the procedure, showed that resorption times for the bMBL were shorter as the diameter of the implant became wider. The implant CSR was 92% in native areas (two failures/25 implants) and 93.3% in sinuses lifted with particulate bone (two failures/30 implants).
Conclusions
The results suggest that a protrusion of the implant apices into augmented sinus lift occurred, whereas the bone remodelling of the coronal areas was not influenced by the events in the maxillary sinus. A diameter ranging from 4 to 5 mm might better guarantee a conservation of marginal peri‐implant bone level compared with implants with smaller diameters.
Objective: A re‐pneumatization phenomenon was recorded in sinuses grafted with different materials. The specific aims of this paper were to assess the dental implant survival rate and the behavior of ...marginal and apical bone remodeling around dental implants placed following sinus augmentation.
Materials and methods: A retrospective study was conducted on consecutive patients treated in two surgical centers. Different surgical techniques were adopted for sinus augmentation: simultaneous or delayed dental implant insertion with bovine bone‐material augmentation or autologous bone grafting (chin and iliac crest). Survival rates were recorded for the overall number of implants (patients of group A). Apical and marginal bone levels (ABL and MBL, respectively) were radiographically measured, and statistical analysis was performed in implants of a subgroup of patients (group B).
Results: A total of 282 dental implants were positioned. Recorded cumulative survival rates (CSRs) were 95.6% and 100% for autogenous and bovine bone material, respectively, while CSRs at 2‐year follow‐up for immediate and delayed procedures were 99.3% and 96.5%. For the subgroup B, 57 sinus augmentation procedures were performed in 39 patients, with the positioning of 154 implants. Generally, the apical‐ and marginal‐bone resorption of the bovine bone‐material group was less than that of the autogenous group. The differences between the ABL values of the bovine bone‐material and iliac‐crest groups were statistically significant at 1 year, whereas this significance disappeared at the 2‐year follow‐up; tests showed that a statistical difference was recorded in the bovine bone‐material group between the 1‐ and 2‐year follow‐ups. With regard to MBL comparisons between simultaneous and delayed implantation, the differences maintained their significance at the 2‐year follow‐up also.
Conclusions: Differences regarding apical bone alteration between autogenous bone from the iliac crest and bovine bone material at the 1‐ and 2‐year follow‐ups, as well as in the bovine bone‐material group between the 1‐ and 2‐year follow‐ups, attested to slower but more prolonged physiologic bone remodeling in the bovine‐graft‐material group than in the autogenous‐bone group. The MBL analysis showed that remodeling in the delayed implant group demonstrated a greater resorption in the cervical portion than was seen in the simultaneous implant group.
To cite this article:
Sbordone L, Levin L, Guidetti F, Sbordone C, Glikman A, Schwartz‐Arad D. Apical and marginal bone alterations around implants in maxillary sinus augmentation grafted with autogenous bone or bovine bone material and simultaneous or delayed dental implant positioning. Clin. Oral Impl. Res22, 2011; 485–491 doi: 10.1111/j.1600‐0501.2010.02030.x
This article discusses a 3-year retrospective survey of implant clinical survival and computerized tomographic analysis of bone remodeling in atrophic alveolar crests reconstructed via various ...autogenous bone grafting procedures and in similar regions of native bone.
The retrospective chart review included consecutive edentulous patients with severe alveolar crest atrophy treated between 2000 and 2002 with onlay autogenous bone grafts in the mandible and anterior maxilla (as needed) and implant insertion. Implant recipients were followed for 3 years. Defective areas were reconstructed by bone graft harvested from the chin or iliac crest. Implants in reconstructed areas were divided into two groups according to graft source. Implants in corresponding native areas served as controls. Cumulative survival rate (CSR), survival rate, and confidence interval (CI) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were compared for statistically significant differences by Wilcoxon signed-rank test with a significance level a = .05.
Forty patients were treated with 109 screw-type, root-form, rough-surfaced implants inserted in 48 onlay grafts; 88 implants were placed in native bone. The implant 3-year CSRs were 98.9% (CI 96.7% to 100%) in native bone and 99.1% (CI 97.3% to 100%) in onlay grafts, irrespective of bone source. Mean resorption in the maxilla was 4.6 +/- 0.9 mm buccally and 3.8 +/- 0.8 mm palatally in areas reconstructed with chin grafts, 3.4 +/- 1.7 mm buccally and 2.6 +/- 1.4 mm palatally in areas reconstructed with iliac crest grafts, and 3.2 +/- 1.2 mm buccally and 2.1 +/- 0.9 mm palatally in native areas.
Similar implant CSRs were seen in native and grafted sites. Maximal implant CSR was observed in onlay grafts from the chin despite more marked linear bone remodeling in this group as compared to iliac crest grafts or native bone.
The present study was a 3-year follow-up evaluation of implant clinical success and radiographic bone remodeling in sinus floors elevated with different autogenous bone-grafting procedures and in ...similar native bone regions.
This retrospective chart review examined consecutive edentulous patients with severe jaw atrophy treated between 2000 and 2002 via sinus lift, when needed, and implant insertion. Implants in sinus lift areas were divided into four groups by graft source (iliac crest, chin area) and technique (bone block, particulate). Implants positioned in native areas beneath the sinus floor served as controls. The cumulative success rate (CSR) and success rate (SR) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were statistically compared with the Wilcoxon signed rank test.
Twenty-eight patients were treated in the posterior maxilla via insertion of 70 screw-type, root-form, rough implants in 39 sinus-lifted areas. All surgical procedures were uneventful. Twenty-four implants were positioned in native areas beneath the sinus floor. The implant CSR was 95.8% in native areas (one failure/24 implants), 85% in sinuses lifted with particulate chin bone (three failures/20 implants), and 100% in the other three groups (eight in particulate iliac crest, 20 in chin block, and 22 in iliac crest block). Computerized tomographic scans revealed that bone remodeling around apices caused implants to bulge into the sinuses in both particulate bone graft groups. Crestal remodeling around implant necks was similar for all groups.
The use of particulate chin bone grafts in sinus lift procedures does not seem to yield optimal outcomes. Milled iliac crest and chin bone tends to remodel around the implant apices, leading to bulging within the sinuses. Grafting sinuses with either chin or.iliac crest bone blocks yields the highest implant success rates and stable sinus floors.
