Collagen membranes at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of resorbable membranes on hard tissue alterations and osseointegration at implants placed into extraction sockets in a dog model. Material and methods: In the mandibular premolar region, implants were installed immediately into the extraction sockets of six Labrador dogs. Collagen‐resorbable membranes were placed at the test sites, while the control sites were left uncovered. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, a control implant was not integrated (n=5). Both at the test and at the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between the test and the control sites, the alveolar bone crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 1.7 mm) compared with the control sites (loss: 2.2 mm). Conclusions: The use of collagen‐resorbable membranes at implants immediately placed into extraction sockets contributed to a partial (23%) preservation of the buccal outline of the alveolar process. To cite this article:
Caneva M, Botticelli D, Salata LA, Souza SLS, Carvalho Cardoso L, Lang NP. Collagen membranes at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 891–897.
doi: 10.1111/j.1600‐0501.2010.01946.x     

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs

Objectives: To evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets. Material and methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results: With one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7±0.4 mm) than at the control implants (1.5±0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants. Conclusions: The installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants. To cite this article:
Caneva M, Salata LA, de Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 885–895.
doi: 10.1111/j.1600‐0501.2010.01931.x     

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of magnesium‐enriched hydroxyapatite (MHA) (SintLife^®) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. Material and methods: In the mandibular pre‐molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. Conclusions: The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest. To cite this article:
Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium‐enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 512–517
doi: 10.1111/j.1600‐0501.2010.02040.x     

Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs

Aim: To evaluate the influence of implant positioning into extraction sockets on osseointegration. Material and methods: Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results: All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2±0.9 mm and 0.6±0.9 mm, respectively (P<0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS). Conclusions: From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant. To cite this article:
Caneva M, Salata LA, de Souza SS, Baffone G, Lang NP, Botticelli D. Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs.
Clin. Oral Impl. Res. 21 , 2010; 43–49.     

Influence of a microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs

Objective: This study compared the alveolar bone reduction after immediate implantation using microgrooved and smooth collar implants in fresh extracted sockets. Material and methods: Four mongrel dogs were used in this study. The full buccal and lingual mucoperiosteal flaps were elevated and the third and fourth premolars of the mandible were removed. The implants were installed in the fresh extracted sockets. The animals were sacrificed after a 3‐month healing period. The mandibles were dissected and each implant site was removed and processed for a histological examination. Results: During healing, the marginal gaps in both groups, which were present between the implant and the socket walls at implantation, disappeared as a result of bone filling and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12‐week interval, the mean bone–implant contact in the microgrooved group was significantly higher than that of the turned surface group. From the observations in some of the microgrooved groups, we have found bone attachment to the 12 μm microgrooved surface and collagen fibers perpendicular to the long axis of the implants over the 8 μm microgrooved surface. Conclusion: Within the limitations of this study, microgrooved implants may provide more favorable conditions for the attachment of hard and soft tissues and reduce the level of marginal bone resorption and soft tissue recession. To cite this article:
Shin S‐Y., Han D‐H. Influence of microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs.
Clin. Oral Impl. Res. 21 , 2010; 804–814.
doi: 10.1111/j.1600‐0501.2010.01917.x     

Vertical and horizontal ridge alterations after tooth extraction in the dog: flap vs. flapless surgery

Objective: To compare ridge alterations after flap and flapless tooth extraction in the vertical and horizontal dimension in the dog model. Material and methods: This study was carried out on five Beagle dogs. Four extractions were performed in the lower jaw of each dog (two per side. Pm3, Pm4). At the time of tooth extraction, flap surgery was performed on one side (control group). On the contra‐lateral side, a flapless extraction was performed (test group). Mesial sockets were left untreated on both sides. After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. Results: Ten samples were evaluated on each group. The vertical difference in height between the buccal and lingual crest was 1.48 mm for the flap, and 1.22 mm for the flapless group. The horizontal dimension of the ridge was 4.41 mm (at 1 mm from the crest), 5.72 mm (at 3 mm from the crest) and 6.67 mm (at 5 mm form the crest) in the flap group. In the flapless group, the measurements were 4.5, 5.58 mm and 6.44 at 1, 3 and 5 mm from the crest, respectively. Conclusion: Evaluating ridge alterations in the vertical and horizontal dimension after 3 months of healing following tooth extraction, results for the flap and the flapless group were very similar. To cite this article:
Blanco J, Mareque S, Liñares A, Muñoz F. Vertical and horizontal ridge alterations after tooth extraction in the dog: flap vs. flapless surgery.
Clin. Oral Impl. Res. 22 , 2011; 1255–1258.
doi: 10.1111/j.1600‐0501.2010.02097.x     

Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs

Aim: To evaluate the influence of deproteinized bovine bone mineral (DBBM) particles concomitant with the placement of a collagen membrane on alveolar ridge preservation and on osseointegration of implants placed into alveolar sockets immediately after tooth extraction. Material and methods: The pulp tissue of the mesial roots of ₃P₃ was removed in six Labrador dogs and the root canals were filled. Flaps were elevated in the right side of the mandible, and the buccal and lingual alveolar bony plates were exposed. The third premolar was hemi‐sectioned and the distal root was removed. A recipient site was prepared and an implant was placed lingually. After implant installation, defects of about 0.6 mm wide and 3.1 mm depth resulted at the buccal aspects of the implant, both at the test and at the control sites. The same surgical procedures and measurements were performed on the left side of the mandible. However, DBBM particles with a size of 0.25–1 mm were placed into the remaining defect concomitant with the placement of a collagen membrane. Results: All implants were integrated into mature bone. No residual DBBM particles were detected at the test sites after 4 months of healing. Both the test and the control sites showed buccal alveolar bone resorption, 1.8±1.1 and 2.1±1 mm, respectively. The most coronal bone‐to‐implant contact at the buccal aspect was 2±1.1 an 2.8±1.3 mm, at the test and the control sites, respectively. This difference in the distance was statistically significant. Conclusion: The application of DBBM concomitant with a collagen membrane to fill the marginal defects around implants placed into the alveolus immediately after tooth extraction contributed to improved bone regeneration in the defects. However, with regard to buccal bony crest preservation, a limited contribution of DBBM particles was achieved. To cite this article:
Caneva M, Botticelli D, Pantani F, Baffone GM, Rangel IG Jr, Lang NP. Deproteinized bovine bone mineral in marginal defects at implants installed immediately into extraction sockets: an experimental study in dogs.
Clin. Oral Impl. Res. 23 , 2012; 106–112.
doi: 10.1111/j.1600‐0501.2011.02202.x     

Extraction Socket Healing in Humans After Ridge Preservation Techniques: Comparison Between Flapless and Flapped Procedures in a Randomized Clinical Trial

Background: The preservation of hard and soft tissue volume, partially lost after tooth removal, can potentially reduce the need for the more demanding augmentation procedures used in implant‐supported rehabilitation. The objective of this research study is to investigate the effect of filling with xenogeneic material the postextractive sockets of two surgical procedures (flapless versus flapped). Methods: In this prospective randomized clinical survey, two types of socket preservation were performed on two groups of patients: the control, treated via full‐thickness mucoperiosteal flap, and the test, via a flapless procedure. Anatomic measurements and related outcome variables at the third month were analyzed using multiway analysis of variance. Multiple comparison tests, using Tukey honestly significant difference test, and appropriate pairwise comparison tests for independent samples were carried out. Results: Sixty‐four patients were treated, 32 for each of the two socket preservation procedures. Statistically significant differences were registered for the output variables — changes in width of keratinized gingiva, changes in bucco‐lingual width, and vertical bone changes at four sites — between the two socket preservation techniques, with P values of <0.001, <0.001, and 0.0105, respectively. Conclusions: A full‐thickness mucoperiosteal flap gave significantly more negative results than that of the less‐demanding flapless procedure, with an increased width resorption of the postextraction site. Moreover, the increased value of the keratinized gingival width attested to the positive outcome of a flapless procedure in terms of soft tissue preservation and improvement. On the other hand, the flapped technique seemed to show less vertical bone resorption on the buccal aspect than the flapless technique.     

Measurement of ridge alterations following tooth removal: a radiographic study in humans

Objective: The aim of this study was a radiographic mesiodistal analysis of the shape of the bone crest 3 months after tooth removal. Material and methods: One hundred single tooth extractions were performed on 100 patients because of orthodontic or prosthetic causes. Bite blocks were used for two radiographs: one on the day of extraction and the other after healing of the socket, 3 months later. These X‐rays were used to determine: (1) the most apical distance of alveolar ridge resorption, with baseline as the line between bone‐to‐teeth contact (the greatest distance in bone resorption height) and (2) the mesiodistal distance (MDD) and mesial and distal angles arising after bone tissue modeling. Results: Significant differences (P<0.05) emerged between the MDDs of multiple‐ [8 mm, 95% confidence interval (CI): 6.09, 9.90] and single‐root teeth (5.60 mm, 95% CI: 4.80, 6.50). However, mesial or distal angles or the most apical distance of alveolar ridge resorption did not differ (mean distance in height=4.32 mm, 95% CI: 3.85, 4.78; mean angle=24°). Conclusions: In this study, the post‐extraction mesiodistal bone distance between teeth adjacent to the edentulous ridge depends on the size of the edentulous space. Nevertheless, the distance does not affect the distance in bone loss height. The distance of bone resorption height reaches a balance at the midpoint, which we consider indicative of stable healing. This resorption process must be considered when placing dental implants in fresh extraction sockets, especially in aesthetic sites, because the implant surfaces could be exposed after 3 months. To cite this article:
Moya‐Villaescusa MJ, Sánchez‐Pérez A. Measurement of ridge alterations following tooth removal: a radiographic study in humans.
Clin. Oral Impl. Res. 21 , 2010; 237–242.
doi: 10.1111/j.1600‐0501.2009.01831.x     

Socket grafting with the use of autologous bone: an experimental study in the dog

Background: Studies in humans and animals have shown that following tooth removal (loss), the alveolar ridge becomes markedly reduced. Attempts made to counteract such ridge diminution by installing implants in the fresh extraction sockets were not successful, while socket grafting with anorganic bovine bone mineral prevented ridge contraction. Aim: To examine whether grafting of the alveolar socket with the use of chips of autologous bone may allow ridge preservation following tooth extraction. Methods: In five beagle dogs, the distal roots of the third and fourth mandibular premolars were removed. The sockets in the right or the left jaw quadrant were grafted with either anorganic bovine bone or with chips of autologous bone harvested from the buccal bone plate. After 3 months of healing, biopsies of the experimental sites were sampled, prepared for buccal–lingual ground sections and examined with respect to size and composition. Results: It was observed that the majority of the autologous bone chips during healing had been resorbed and that the graft apparently did not interfere with socket healing or processes that resulted in ridge resorption. Conclusion: Autologous bone chips placed in the fresh extraction socket will (i) neither stimulate nor retard new bone formation and (ii) not prevent ridge resorption that occurs during healing following tooth extraction. To cite this article:
Araújo MG, Lindhe J. Socket grafting with the use of autologous bone: an experimental study in the dog.
Clin. Oral Impl. Res. 22 , 2011; 9–13.
doi: 10.1111/j.1600‐0501.2010.01937.x     

Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis

Aim: To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket. Material and methods: Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re‐entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S‐OC), (ii) the horizontal residual gap (S‐IC), (iii) the vertical residual gap (R‐D) and (iv) the vertical position of the bone crest opposite the implant (R‐C). Results: It was demonstrated that (i) the S‐OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco‐lingual implant position influenced the amount of buccal crest resorption. Conclusions: Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing. To cite this article:
Tomasi C, Sanz M, Cecchinato D, Pjetursson B, Ferrus J, Lang NP, Lindhe J. Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis.
Clin. Oral Impl. Res. 21 , 2010; 30–36.     

Bio-Oss collagen in the buccal gap at immediate implants: a 6-month study in the dog

Background: Following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. Objective: The objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. Material and methods: Five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible (₄P₄) were selected and used as experimental sites. The premolars were hemi‐sected and the distal roots removed and, subsequently, implants were inserted in the distal sockets. In one side of the jaw, the marginal buccal‐approximal void that consistently occurred between the implant and the socket walls was grafted with Bio‐Oss^® Collagen while no grafting was performed in the contra‐lateral sites. After 6 months of healing, biopsies from each experimental site were obtained and prepared for histological analyses. Results: The outline of the marginal hard tissue of the control sites was markedly different from that of the grafted sites. Thus, while the buccal bone crest in the grafted sites was comparatively thick and located at or close to the SLA border, the corresponding crest at the control sites was thinner and located a varying distance below SLA border. Conclusions: It was demonstrated that the placement of Bio‐Oss^® Collagen in the void between the implant and the buccal‐approximal bone walls of fresh extraction sockets modified the process of hard tissue healing, provided additional amounts of hard tissue at the entrance of the previous socket and improved the level of marginal bone‐to‐implant contact. To cite this article:
Araújo MG, Linder E, Lindhe J. Bio‐Oss^® Collagen in the buccal gap at immediate implants: a 6‐month study in the dog.
Clin. Oral Impl. Res. 22 , 2011; 1–8.
doi: 10.1111/j.1600‐0501.2010.01920.x     

Radiographic evaluation of marginal bone levels during healing period,adjacent to parallel‐screw cylinder implants inserted in the posterior zone of the jaws,placed with flapless surgery

Objective: The purpose of this study was to compare changes at the marginal bone level adjacent to implants placed with flapless surgery and flap surgery during a stress‐free healing period. Material and methods: Seven hundred and eighty‐five implants were placed in 417 patients with a flapless approach and 459 implants were placed in 227 patients using flap techniques. The marginal bone level was determined radiographically, using digitized panoramic radiographs, at two time points: at implant placement (baseline) and after the healing period. Results: The median follow‐up time was 0.5 years (SD, 1.2; range: 0.3–0.7). Implants placed with flapless surgery had a mean crestal bone loss of 0.5 mm (SD, 0.5; range: ?0.7–2.4) and implants placed with flap surgery had a mean bone loss of 0.5 mm (SD, 0.7; range: ?2.0–3.0) after healing. Differences in bone level changes between smokers and non‐smokers were statistically significant for the flapless group (P<0.01). Conclusions: A radiographic evaluation of marginal bone levels adjacent to implants showed comparable results for implants placed with flapless surgery and flap surgery. Appropriate case selection after virtual planning of the implant position and a sound surgical protocol is necessary for flapless surgery. Smoking habits may compromise the efficacy of flapless implant procedures. To cite this article:
Nickenig H‐J, Wichmann M, Schlegel KA, Nkenke E, Eitner S. Radiographic evaluation of marginal bone levels during healing period, adjacent to parallel‐screw cylinder implants inserted in the posterior zone of the jaws, placed with flapless surgery.
Clin. Oral Impl. Res. 21 , 2010; 1386–1393.
doi: 10.1111/j.1600‐0501.2009.01961.x     

Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in Beagle dogs

Introduction: After a tooth extraction, the height of the buccal wall tends to decrease. The literature indicates that regenerative techniques (guided bone regenerative [GBR] techniques) have succeeded in improving the bone levels. Therefore, this experiment set out to compare the physiological bone remodelling in Beagle dog models after implant placement in a fresh extraction socket, with and without the application of regenerative procedure. Materials and methods: Five dogs were used in this study. Test and control sites were randomly selected. The experimental teeth (fourth pre‐molar and first molar) were hemi‐sected removing the distal roots and placing implants. Porcine bone was placed to fill the gap around the implant on the test sites and a reabsorbable membrane was used to cover the area. The dogs were put down at different times (2 weeks, 1 month and 3 months). The measurements were taken immediately and at 2, 4, 12 weeks after implant placement. Student's test for paired data was used to compare the means of the clinical measurements. Results: At 2 weeks: On the control sites, few signs of resorption were detected at the first molar only, while at the test sites bone levels were placed at the implant shoulder or above. At 4 weeks: On the control site, slight bone remodelling was observed, while on the test site minor signs of resorption or an increase of bone levels were detected. At 12 weeks: The alveolar crest on the control sites showed various degrees of remodelling. On the test sites stable bone levels or an increase of bone crest was observed. Conclusion: With the limits of this study, the findings showed that GBR techniques were able to limit resorption of the alveolar crest after tooth extraction. A pattern of bone remodelling after tooth extraction and implant placement was observed in the control sites (no GBR) as well as in test sites (GBR), and although the exact cause of this is unclear, surgical trauma could play a role. Further studies are necessary to confirm these results and to clarify the precise causes of bone remodelling in fresh extraction sockets. To cite this article:
Barone A, Ricci M, Calvo‐Guirado JL, Covani U. Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in the Beagle dogs.
Clin. Oral Impl. Res. 22 , 2011; 1131–1137
doi: 10.1111/j.1600‐0501.2010.02084.x     

Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs

Aim: To compare the influence of autologous or deproteinized bovine bone mineral as grafting material on healing of buccal dehiscence defects at implants installed immediately into the maxillary second incisor extraction socket in dogs. Material and methods: In the maxillary second incisor sockets of 12 Labrador dogs, implants were installed immediately following tooth extraction. A standardized buccal defect was created and autologous bone particles or deproteinized bovine bone mineral were used to fill the defects. A collagen membrane was placed to cover the graft material, and the flaps were sutured to fully submerge the experimental areas. Six animals were sacrificed after 2 months, and six after 4 months of healing. Ground sections were obtained for histological evaluation. Results: After 2 months of healing, all implants were osseointegrated. All buccal dehiscence defects were completely filled after 2 months irrespective of the augmentation material (autologous bone or Bio‐Oss^®) applied. Bone‐to‐implant contact (BIC) on the denuded implant surfaces was within a normal range of 30–40%. However, the newly formed tissue at 2 months was partially resorbed (>50% of the area measurements) after 4 months. Conclusions: Applying either autologous bone or deproteinized bovine bone mineral to dehiscences at implants installed immediately into extraction sockets resulted in high degree of regeneration of the defects with satisfactory BIC on the denuded implant surface. To cite this article:
De Santis E, Botticelli D, Pantani F, Pereira FP, Beolchini M, Lang NP. Bone regeneration at implants placed into extraction sockets of maxillary incisors in dogs.
Clin. Oral Impl. Res. 22 , 2011; 430–437.     

Clinical and histomorphometric evaluation of extraction sockets treated with an autologous bone marrow graft

Purpose: The aim of this study was to evaluate the potential of an autologous bone marrow graft in preserving the alveolar ridges following tooth extraction. Materials: Thirteen patients requiring extractions of 30 upper anterior teeth were enrolled in this study. They were randomized into two groups: seven patients with 15 teeth to be extracted in the test group and six patients with 15 teeth to be extracted in the control group. Hematologists collected 5 ml of bone marrow from the iliac crest of the patients in the test group immediately before the extractions. Following tooth extraction and elevation of a buccal full‐thickness flap, titanium screws were positioned throughout the buccal to the lingual plate and were used as reference points for measurement purposes. The sockets were grafted with an autologous bone marrow in the test sites and nothing was grafted in the control sites. After 6 months, the sites were re‐opened and bone loss measurements for thickness and height were taken. Additionally, before implant placement, bone cores were harvested and prepared for histologic and histomorphometric evaluation. Results: The test group showed better results (P<0.05) in preserving alveolar ridges for thickness, with 1.14±0.87 mm (median 1) of bone loss, compared with the control group, which had 2.46±0.4 mm (median 2.5) of bone loss. The height of bone loss on the buccal plate was also greater in the control group than in the test group (P<0.05), 1.17±0.26 mm (median 1) and 0.62+0.51 (median 0.5), respectively. In five locations in the control group, expansion or bone grafting complementary procedures were required to install implants while these procedures were not required for any of the locations in the test group. The histomorphometric analysis showed similar amounts of mineralized bone in both the control and the test groups, 42.87±11.33% (median 43.75%) and 45.47±7.21% (median 45%), respectively. Conclusion: These findings suggest that the autologous bone marrow graft can contribute to alveolar bone repair after tooth extraction. To cite this article:
Pelegrine AA, da Costa CES, Correa MEP, Marques JFC Jr. Clinical and histomorphometric evaluation of extraction sockets treated with an autologous bone marrow graft.
Clin. Oral Impl. Res. 21 , 2010; 535–542.
doi: 10.1111/j.1600‐0501.2009.01891.x     

Effect of immediate or delayed loading following immediate placement of implants with a modified surface

Objective: To evaluate the effect of the timing of loading on bone‐to‐implant contact (BIC) following immediate placement of implants with a hydrophilic sandblasted, large‐grit and acid‐etched surface (modSLA) into fresh extraction sockets in a minipig model. Material and methods: Six minipigs were used in this study. In each hemi‐mandible, two conical shape implants (TE, Straumann implants) with a hydrophilic surface (modSLA) were placed in fresh extraction sockets. In one side of the mandible (control), two implants were immediately placed in fresh extraction sockets. The implants were loaded after 4 weeks of healing. At the contralateral side (test), two implants were immediately placed and loaded. After 8 weeks of healing, the animals were sacrificed and histologically analysed. Results: During the experimental period, no implants were lost and all of them presented to be osseointegrated. The percentage of BIC was similar in both groups: 66.1% and 65.1% for the control and test group, respectively. Furthermore, the distance from the shoulder of the implant to bone crest and the distance from the shoulder to the first BIC were similar in both groups. Conclusion: Immediate implant placement and loading showed similar BIC with immediate placement and delayed loading when implants with a modSLA surface were used. Both procedures showed similar buccal bone crest levels, which presented some resorption irrespective of the treatment modality. To cite this article:
Liñares A, Mardas N, Dard M, Donos N. Effect of immediate or delayed loading following immediate placement of implants with a modified surface.
Clin. Oral Impl. Res. 22 , 2011; 38–46.
doi: 10.1111/j.1600‐0501.2010.01988.x     

Establishment of the epithelial attachment and connective tissue adaptation to implants installed under the concept of "platform switching": a histologic study in minipigs

Aim: To validate the “platform switching” concept at oral implants with respect to the preservation of the alveolar crestal bone levels in an animal model. Material & methods: Five minipigs received three implants each with a 0.25 mm implant/abutment mismatch and were placed flush (T₀), 1 mm below (T₁) and 1 mm above (T₊₁) the alveolar bony crest, and as a control, one conventionally restored implant placed at the bone level. The implants were randomly inserted flapless into the mandible. Four months after implant insertion, the animals were sacrificed, and undecalcified block sections were obtained and used for histological analyses. Results: The mean values for peri‐implant bone resorption were 1.09±0.59 mm (Control), 0.51 (±0.27 mm, T₀), 0.50 (±0.46 mm, T₊₁) and 1.30 (±0.21 mm, T_?1), respectively. Statistically significant differences (P<0.05) were found among the test (T₀, T_?1) and the control sites. Control implants presented an average biologic width length of 3.20 mm (±0.33), with a connective tissue adaptation compartment of 1.29 mm (±0.53) and an epithelial attachment of 1.91 mm (±0.71). T₀, T₊₁ and T_?1 implants presented with a mean biologic width of 1.97mm (± 1.20), 2.70mm (± 1.36) and 2.84mm (± 0.90), respectively, with a connective tissue adaptation compartment of 1.21mm (± 0.97), 1.21mm (± 0.65) and 1.50mm (± 0.70) and an epithelial attachment of 0.84mm (± 0.93), 1.66mm (±0.88) and 1.35mm (± 0.44), respectively. Differences between the configurations were mainly associated with the length of the epithelial attachment. The epithelial attachment was significantly longer in the C sites than in T₀ (P=0.014). However, no other differences between configurations were detected. Conclusion: If the implants are positioned at the level of the alveolar bony crest, the platform‐switching concept may have a minor impact on the length of the epithelial attachment (0.84 vs. 1.91 mm), while the connective tissue adaptation compartment remains relatively unaffected. Moreover, platform switching resulted in less resorption of the alveolar crest (0.58 mm). To cite this article:
Farronato D, Santoro G, Canullo L, Botticelli D, Maiorana C, Lang NP. Establishment of the epithelial attachment and connective tissue adaptation to implants installed under the concept of “platform switching”: a histologic study in minipigs
Clin. Oral Impl. Res. 23 , 2012; 90–94.
doi: 10.1111/j.1600‐0501.2011.02196.x     

Comparison of Crestal Bone Loss Around Dental Implants Placed in Healed Sites Using Flapped and Flapless Techniques: A Systematic Review

Background : The aim of the present systematic review is to compare the crestal bone loss (CBL) around dental implants placed in healed sites using flapped and flapless surgical techniques. Methods: The focused question was, “Does flapped and flapless surgical technique influence CBL around dental implants placed in healed sites?” Databases were searched from 1975 up to and including May 2014 using different combinations of the following keywords: “crestal bone loss”; “dental implant”; “surgery”; “flap”; and “flapless.” Unpublished data, experimental studies, letters to the editor, review articles, case reports, commentaries, and articles published in languages other than English were excluded. In all studies, the test group comprised implants placed using flapless surgery, and the control group, implants placed after reflection of a full‐thickness mucoperiosteal flap. Results: Ten clinical studies were included. In five studies, CBL around implants was comparable between the test and control groups. In four studies, implants in the test group showed significantly less CBL compared with the control group. In one study, CBL was significantly higher in the test group than the control group. Conclusion: CBL around dental implants placed in healed sites using flapped and flapless techniques is comparable.     

Tissue alterations after tooth extraction with and without surgical trauma: a volumetric study in the beagle dog

Objectives: The aim of this study is to evaluate whether tooth extraction without the elevation of a muco‐periosteal flap has advantageous effects on the resorption rate after tooth extraction. Material and Methods: In five beagle dogs polyether impressions were taken before the surgery. The roots of the first and second pre‐molars (P₁ and P₂) were extracted and the sites were assigned to one of the following treatments: treatment group (Tx) 1, no treatment; Tx 2, surgical trauma (flap elevation and repositioning); Tx 3, the extraction socket was filled with BioOss Collagen^® and closed with a free soft‐tissue graft; Tx 4, after flap elevation and repositioning, the extraction socket was treated with BioOss Collagen^® and a free soft‐tissue graft. Impressions were taken 2 and 4 months after surgery. The casts were scanned, matched together with baseline casts and evaluated with digital image analysis. Results: The “flapless groups” demonstrated significant lower resorption rates both when using socket‐preservation techniques and without. Furthermore, socket‐preservation techniques yielded better results compared with not treating the socket. Conclusion: The results demonstrate that leaving the periosteum in place decreases the resorption rate of the extraction socket. Furthermore, the treatment of the extraction socket with BioOss Collagen^® and a free gingival graft seems beneficial in limiting the resorption process after tooth extraction.