Histomorphometric Study In Dogs Research Articles

Influences of standardized clinical probing on peri-implant soft tissue seal in a situation of peri-implant mucositis: A histomorphometric study in dogs.

Clinical probing is commonly recommended to evaluate peri-implant conditions. In a situation of peri-implant mucositis or peri-implantitis, the peri-implant seal healing from the disruption of soft tissue caused by probing has not yet been studied. This study aimed to investigate soft tissue healing after standardized clinical probing around osseointegrated implants with peri-implant mucositis in a dog model. Three transmucosal implants in each hemi-mandible of six dogs randomly assigned to the peri-implant healthy group or peri-implant mucositis group were probed randomly in the mesial or distal site as probing groups (PH or PM), the cross-sectional opposite sites as unprobed control groups. Histomorphometric measurements of implant shoulder (IS)-most coronal level of alveolar bone contact to the implant surface (BCI), apical termination of the junctional epithelium (aJE)-BCI, mucosal margin (MM)-BCI, and MM-aJE were performed at 1day, 1week, and 2weeks after probing. Apoptosis, proliferation, proinflammatory cytokines, and matrix metalloproteinases (MMPs) of peri-implant soft tissue were estimated by immunofluorescent analysis. In the PM group, apical migration of junctional epithelium was revealed by significantly decreased aJE-BCI from 1day to 2weeks in comparison to unprobed sites (p<0.05), while no significant differences were found in the PH group. Immunofluorescent analysis showed higher levels of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), MMP-1, and MMP-8, together with exaggerated apoptosis and proliferation of peri-implant soft tissue in the PM group. Within the limitations, standardized clinical probing might lead to apical migration of the junctional epithelium in a situation of peri-implant mucositis.

Cross-linked hyaluronic acid gel with or without a collagen matrix in the treatment of class III furcation defects: A histologic and histomorphometric study in dogs.

To histologically evaluate the effects of cross-linked hyaluronic acid (xHyA) with or without a collagen matrix (CM) on periodontal wound healing/regeneration in class III furcation defects in dogs. Class III furcation defects were surgically created in the mandibular premolars in six beagle dogs. The defects were randomly treated as follows: open flap debridement (OFD) + CM (CM), OFD + xHyA (xHyA), OFD + xHyA + CM (xHyA/CM) and OFD alone (OFD). At 10 weeks, the animals were euthanized for histological evaluation. The newly formed bone areas in the xHyA (4.04 ± 1.51 mm2 ) and xHyA/CM (4.32 ± 1.14 mm2 ) groups were larger than those in the OFD (3.25 ± 0.81 mm2 ) and CM (3.31 ± 2.26 mm2 ) groups. The xHyA (6.25 ± 1.45 mm) and xHyA/CM (6.40 ± 1.35 mm) groups yielded statistically significantly (p< .05) greater formation of new connective tissue attachment (i.e., new cementum, with inserting connective tissue fibres) compared with the OFD (1.47 ± 0.85 mm) group. No significant differences were observed in any of the histomorphometric parameters between the xHyA and xHyA/CM groups. Complete furcation closure was not observed in any of the four treatment modalities. Within their limits, the present results suggest that the use of xHyA with or without CM positively influences periodontal wound healing in surgically created, acute-type class III furcation defects.

Evaluating systemic administration effect of propranolol on osseointegration around titanium implants: A histomorphometric study in dogs

Dental implants are known as a widely accepted and predictable method to replace missing teeth. Many factors, including using a class of drugs, such as β-blockers, can improve the osseointegration of dental implants. This study aimed to investigate the relationship between administrating propranolol and osseointegration in dental implants. This experimental animal study was performed on four native male street dogs of 11-13 kg of weight and 16-20 months of age. The specimens underwent teeth extraction. After that, the dogs were randomly divided into two groups. The first group contains two control dogs which would receive oral saline. The second contains two dogs which would receive oral tablets of propranolol daily. After a period of healing, three titanium implants were inserted in each of speciments' left mandibular quadrant, and treatment was resumed with propranolol and saline administration in case and control group, respectively. After 4 weeks, one of control group dogs and one of case group were anesthetized, and dental implants were removed alongside the peripheral bone marrow using a trephine drill. Meanwhile, the other two dogs (1 control and 1 propranolol administered dogs) were anesthetized after 9 weeks of implant placement, and the same procedure was carried out. Due to the histomorphometric assessment, the mean score of bone implant contact (BIC) in week 4 was significantly higher in case group compared to control one (68.33% vs. 20.22%). In week 9, the mean BIC score was higher in case group compared to control group (68.60% vs. 50.17%); meanwhile, in contrast to week 4, it was not statistically significant. In both case and control groups, the formation of woven and lamellar bone was more significant in week 4 rather than week 9. Administration of systemic β-blockers can improve dental implants osseointegration process.

Peri-implant tissue alteration around tissue-level and bone-level implants in fresh extraction sockets: a histomorphometric study in dogs.

BackgroundTo compare tissue alteration in fresh extraction sockets between bone-level and tissue-level implants with different neck designs.MethodsBilateral premolars of 6 adult Labrador dogs were extracted, and 24 bone-level and tissue-level implants with two different neck designs were immediately placed. At the same time, buccal bony wall thickness in fresh extraction sockets was also recorded. The Straumann® Bone Level (BL) and Standard Plus (SP) implants were positioned at two insertion depths: 1mm below and flush with the alveolar crest. All animals were sacrificed 6 months after the implant placement. Undecalcified block sections were obtained for histological measurement. Vertical bone resorption and biological widths were documented. Statistical analysis consisted of two sample t-test and Wilcoxon sign-rank test.ResultsAll implants were histologically osseointegrated. There was no significant difference between BL implants and SP implants in vertical bone resorption regardless of the insertion depths (P>0.05). Meanwhile, significant difference was found in lingual biological width between BL (3.16 mm) and SP (2.43 mm) implants when placed 1mm below the alveolar crest (P<0.05).ConclusionsWithin the limits, it seemed that different implant neck designs had little effect on bone remodeling in fresh extraction sockets. However, longer biological width was found in bone-level implants.

Effect of systemic administration of omeprazole on osseointegration around titanium dental implants: A histomorphometric study in dogs

Dental implants are widely accepted substitutes for replacing missing teeth. Many factors, including the use of specific drugs such as proton-pump inhibitors (PPIs) (omeprazole), can affect the success of dental implantations. The aim of this study was to investigate the relationship between the use of omeprazole and osseointegration of dental implants. This experimental animal study was performed on eight native male dogs weighted 11-13 kg and aged 16-20 months. The dogs were divided into two groups (receivers and nonreceivers of omeprazole). After extraction of mandibular teeth, treatment was started randomly with the administration of omeprazole and saline. After a 2-month recovery period, six titanium implants were placed in the jaws of all dogs and the administration of omeprazole was continued for 2 weeks. After 4 and 12 weeks, the dogs were anesthetized and dental implants with their bone marrow were removed. The samples were examined histomorphometrically to determine osseointegration. Data were analyzed with two-way ANOVA test for 95% confidence interval. The P value was set at 0.05. In the microscopic examination of the samples in week 4, the levels of bone-implant contact (BIC) in the study group were significantly lower than the control group (46.37 vs. 64.37%). In 12 weeks, BIC was significantly lower than that of the control group (67.33 vs. 82.00%). The type of bone formed in week 4 in both the groups was more woven, and in the 12th week, it was mostly lamellar. Systemic administration of PPIs may interfere with osseointegration of dental implants.

The Use of Platelet Rich Fibrin and Nano Hydroxyapatite as Regenerative Treatment of Furcation Class II Defects (A Histomorphometric Study in Dogs)

Objectives: The aim of the present study was to evaluate the use of platelet rich fibrin and Nano-hydroxyapatite as a regenerative treatment in furcation class II defect. Material and methods: Eight young adult dogs was selected for the study; in each dog, class II furcation defects were surgically created in 4 premolars and were treated as follow: First was treated with Nano hydroxyapatite alone ; Second with PRF alone ; Third with Nano hydroxyapatite and PRF ; Fourth did not receive any additional treatment than debridement (controls). Results: histomorphometric analysis revealed that, the greatest amount of newly formed bone was observed in the (PRF+ NHA bone) group, followed by the PRF group, then the NHA group, with the least recorded in the control group. The difference was not statistically significant except in comparing (PRF+ NHA group) with control group (p=0.0035). Conclusion: The combined use of both PRF and Nano hydroxyapatite in treatment of furcation class II defects could accelerate healing processes, getting use of the synergic effect of the powerful inherent regenerative potential of PRF and Nano hydroxyapatite.

Effect of Plasma of Argon Treated Implants on Bone Density: A Randomized, Controlled, Histomorphometric Study in Dogs

Background: Altering surface characteristics by increasing its energy and hydrophilicity will accelerate the interaction between cells and implant surface. Energy and hydrophilicity tend to disappear over a short time. The implant surface may be reactivated by the use of argon plasma Objective: To assess bone density at cleaned and activated titanium implants using argon plasma. Methods: Mandibular premolars and first molars were extracted bilaterally in eight Beagle dogs. After three months, four implants, two treated with argon plasma (test; plasma) and two left without treatment (control), were randomly installed in one side of the mandible. Abutments were applied on the implants and a non-submerged healing was allowed. After one month, the same surgical procedures were adopted on the opposite side of the mandible. The animals were euthanized after one month and ground sections representing the healing after 1 and 2 months were obtained for histological examination. Results: No statistically significant differences were found between test and control sites (p &lt; 0.05). After 1 month of healing, new bone was 32.5 ± 12.2% and 33.8 ± 8.8% at the plasma and control sites, respectively. After 2 months, the respective values were 50.8 ± 21.5% and 47.6 ± 15.6%. Conclusion: The treatment of the implant surface with argon plasma did not have a significant effect on bone density around implants.

Retraction.

Boquete-Castro A, Gómez-Moreno G, Aguilar-Salvatierra A, Delgado-Ruiz RA, Romanos GE, Calvo-Guirado JL. Influence of the implant design on osseointegration and crestal bone resorption of immediate implants: a histomorphometric study in dogs. Clin Oral Impl Res. 2014;26: 876-881. The above article, published online on 26 March 2014 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 26, pp. 876-881, has been retracted by agreement between the journal Editor in Chief, L Heitz-Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to numerical discrepancies in Tables 1-4, resulting in unreliable data. Reference Boquete-Castro A, Gómez-Moreno G, Aguilar-Salvatierra A, Delgado-Ruiz RA, Romanos GE, Calvo-Guirado JL. Influence of the implant design on osseointegration and crestal bone resorption of immediate implants: a histomorphometric study in dogs. Clin Oral Impl Res. 2014;26: 876-881. https://doi.org/10.1111/clr.12381.

Immediate and delayed loading of fixed dental prostheses supported by single or two splinted implants: A histomorphometric study in dogs.

To evaluate presumptive differences in osseointegration at implants supporting crowns that are physiologically loaded either immediately or 3months after installation. All premolars and first molars were extracted bilaterally in six dogs. After 3months of healing, three implants were installed on the premolar region and two in the molar region in one side of the mandible. Likewise, after another 3months, five implants were installed in the contralateral side, and impressions were taken bilaterally. Within 48hours, two single crowns were screwed bilaterally onto two implants in the premolar region, and two splinted crowns reproducing the shape of the first molar were screwed bilaterally onto the implants in the molar region. The mesial implants were used as no-loaded controls. Sacrifices were performed after 3months, and histological analyses were performed. At the premolar sites, mineralised bone-to-implant contact (MBIC%) was 78.0±4.0% and 70.9±7.9% at the delayed and immediately loaded sites, respectively. This difference was statistically significant. At the control implants, MBIC% was 61.4±14.7% and 63.1±13.1% at the delayed and the immediately loaded sites, respectively. At the molar sites, MBIC% was 79.2±10.9% and 61.1±10.3% at the delayed and immediately loaded sites, respectively. Applying a delayed loading to fixed dental prostheses supported by single or two splinted implants yielded higher proportions of bone-to-implant contact (osseointegration) compared to immediately loaded implants. Moreover, both types of loading protocols yielded a higher rate of osseointegration compared to unloaded implant sites after 3months following implant installation.

Soft Tissue and Marginal Bone Adaptation on Platform-Switched Implants with a Morse Cone Connection: A Histomorphometric Study in Dogs.

The purpose of this study was to investigate peri-implant tissue adaptation on platform-switched implants with a Morse cone-type connection, after 3 and 12 weeks of healing in dogs. Ten weeks after mandibular premolar extractions, eight beagle dogs received three implants each. At each biopsy interval, four animals were sacrificed and biopsies were processed for histologic analysis. The height of the peri-implant mucosa was 2.32 mm and 2.88 mm, respectively, whereas the bone level in relation to the implant platform was -0.39 mm and -0.67 mm, respectively, after 3 and 12 weeks of healing. Within the limits of the present study, platform-switched implants exhibited reduced values of biologic width and marginal bone loss when compared with previous data.

Retracted: Influence of the implant design on osseointegration and crestal bone resorption of immediate implants: a histomorphometric study in dogs

The aim of this study was to evaluate bone-to-implant contact after immediate implant placement at different levels in relation to crestal bone in American foxhound dogs. The mandibular second, third, and fourth premolars of six American foxhound dogs were extracted bilaterally. Randomly, three immediate implants were placed in the hemimandible of each dog at the bone crest (control group) or 2 mm subcrestally (test group). Three dogs were allowed an 8-week healing period; the other three were left a 12-week healing period. After healing periods, histomorphometric analyses of the specimens were carried out to measure BIC values and bone remodeling. All implants healed uneventfully and were available for histological analysis. The total BIC mean values were 44.52% (± 8.67) and 39.50% (± 9.25) at 8 and 12 weeks, respectively, for the control group, and 47.33% (± 5.23) and 53.85% (± 4.21) at 8 and 12 weeks after healing for the test group, respectively. There was observed less bone resorption in the group of implants placed subcrestally. Our findings suggest that less resorption may be expected when implants are inserted 2 mm subcrestally. Moreover, higher BIC values in the group of subcrestal implants were found.

Osseointegration of zirconia dental implants modified by femtosecond laser vs. zirconia implants in healed bone: a histomorphometric study in dogs with three-month follow-up

Aim The aim of the present study was to evaluate the stability and osseointegration of zirconia dental implants modified by femtosecond laser vs. zirconia implants with sandblasted surface. Materials and methods A total of 48 dental implants were used in this study. After the extraction of premolars (P2, P3, P4) and molars (M1), and 2-months healing period, implants were randomly inserted in both sides of the lower jaw of 6 American Foxhound dogs: 16 zirconia implants with sandblasted surface on endosseous portion (Control Group), 16 zirconia implants with sandblasting and laser modification of the endosseous neck portion only (Test Group A), and 16 zirconia implants with sandblasting and laser modification over the whole endosseous portion (Test Group B). Stability was evaluated by Periotest, while osseointegration was evaluated by Bone-to-implant contact (BIC) assessed by histomorphometry at 1 and 3 months after surgery. Results All implants were stable; Periotest® values (PTV) for Control Group were -5.75 ± 0.22; for Group A -6.125 ± 0.26 and for Group B -7.625 ± 0.27. BIC was greater for group B implants at both 1 and 3 months. No differences between the Control Group and Group A over the examined time periods were detected. Conclusion The present results suggested that the surface treatment of zirconium implants by femtosecond laser increases implant stability and bone to implant contact.

Efficacy of Acellular Dermal Matrix and Coronally Advanced Flaps for the Treatment of Induced Gingival Recession Defects: A Histomorphometric Study in Dogs

Gingival recession (GR) defects can be treated by various methods, including acellular dermal matrix (ADM) or coronally advanced flaps (CAFs). The aim of this histomorphometric experiment is to compare the efficacy of ADM and CAF for treating GR defects in dogs. In eight beagle dogs, a critical-size labial GR defect was surgically induced on bilateral maxillary cuspids under general anesthesia. Test sites received ADM and CAF, and control sites underwent CAF treatment alone. Plaque index (PI), bleeding index (BI), and gingival index (GI) were measured at 4 weeks (baseline), 8 weeks, and 16 weeks. Width of keratinized gingiva (KG) was determined at baseline and at 16 weeks. Depth of recession and width of GR below the cemento-enamel junction (CEJ) was also determined. After 4 months, animals were sacrificed, and jaw blocks were histomorphometrically assessed for tissue thickness and distance from the stent to the gingival margin (GM) and to the CEJ. At 4-, 8-, and 16-week intervals, there was no significant difference in the BI, GI, and PI at the test and control sites. At 16 weeks, thickness of KG was significantly higher at the control sites than test sites (P <0.01). There was no difference in the midfacial recession depth and recession width at the test and control sites at baseline and before euthanasia (16 weeks). Histomorphometrically, there was no significant difference in tissue thicknesses and distances from the stent to the GM and CEJ in the test and control sites. ADM might yield similar results to a CAF alone and could decrease the amount of KG.

Differences in collagen distribution of healthy and regenerated periodontium. Histomorphometric study in dogs.

Previous studies have shown that there is a relationship between periodontal disease and the distribution of collagen fibers. This study evaluated the distribution of collagen types I and III in regenerated bone and periodontal ligament, comparing them to the tissues near the regenerated area and to the healthy periodontium. In the third (P3) and fourth (P4) mandibular premolars of 5 healthy mongrel dogs, bilaterally, buccal class 2 furcation lesions were surgically created and chronified for 3 weeks. After that, full flaps were elevated and expanded polytetrafluoroethylene (e-PTFE) membranes were adapted, sutured and recovered by the flaps. Two weeks after surgery, two membranes on the same side were removed and the other membranes were removed four weeks after surgery. The dogs were euthanized at 12 weeks following placement of the e-PTFE membranes. P3 and P4 teeth as well as the second premolars (healthy control teeth) and their periodontal tissues were removed and histologically processed for Collagen Quantification (COLQ). The amount of type III collagen was higher in native bone compared to the regenerated area. For periodontal ligament, COLQ for type I collagen showed statistically significant differences (Tukeys's Multiple Comparison, p⟨0.05) between the regenerated groups and the control group. These differences were not found for type III COLQ. There are significant differences in collagen distribution among the regenerated, native and control tissues. Membrane removal 2 or 4 weeks postoperatively did not influence the collagen composition.

Buccal bone remodeling after tooth extraction using the flapless approach with and without synthetic bone grafting. A histomorphometric study in dogs

The aim of this study was to evaluate buccal bone remodeling of fresh sockets following tooth extraction using the flapless approach, with or without synthetic graft materials. Eight dogs had the mandibular bicuspids extracted without flaps, and two alveoli on each side (total of 4) were selected. The following groups were devised: one socket on each side received a grafting material (test group), and the other remained only with a blood clot (control group). Ground sections were prepared from 12-week healing biopsies, and histomorphometry was performed. The buccal crest level (BCL) relative to the new bone (i), in the test group, showed numerically better data when compared with the control group, but without statistical relevance. The BCL relative to the old bone (ii) was very similar for the groups without statistical relevance. The alveolar ridge width (ARW) showed similar results without statistically significant difference between the groups. The total bone area (TBA) showed statistically significant differences between the test (38.60%) and control (47.18%) groups. The new bone area (NBA) presents a numerical difference between the test (15.62%) and control (22.24%), but without statistically significant differences. The old bone and the bone marrow were similar for both groups. It was observed that there was no loss of the buccal bone crest in relation to the lingual bone crest, especially in the test group.

Effect of platelet-rich plasma on bone healing of fresh frozen bone allograft in mandibular defects: a histomorphometric study in dogs

This study histologically analyzed the healing of fresh frozen bone allograft (FFBA) with or without platelet-rich plasma (PRP) in bony defects surgically created in the mandible of dogs. Bilateral resection defects were surgically created on the inferior border of the mandible in 10 dogs. The defects were randomly divided into three groups: C (the defect was filled by blood clot only), FFBA (the defect was filled with particulate FFBA), and FFBA/PRP (the defect was filled with particulate FFBA combined with PRP). The animals were euthanized at 12 weeks post-surgery. Histomorphometric and histological analyses were performed. Data were statistically analyzed using Friedman test and Dunn test (P < 0.05). Group FFBA/PRP presented a statistically greater mineralized bone area and a smaller marrow bone area than Groups FFBA and C. The use of PRP improved the incorporation of FFBA, increasing the density of newly formed bone at 12 weeks post-surgery.

Influence of Autologus Adipose Derived Stem Cells and PRP on Regeneration of Dehiscence-Type Defects in Alveolar Bone: A Comparative Histochemical and Histomorphometric Study in Dogs

Autogenous bone grafts is considered to be the best choice for reconstructive surgery. Adipose Derived Stromal Cells (ASCs) represents a promising tool for new clinical concepts in supporting cellular therapy. The goal of our study was to investigate bone regeneration following application of autologous ASCs with or without Platelet-Rich Plasma (PRP) at dehiscence-type defects in alveolar bone in dogs. Standardized buccal dehiscence defects (4× 3×3 mm) were surgically created in eighteen dogs, the defects were grafted with either ASCs -PRP, ASCs alone, or without grafting material. Three months later; a bone core was harvested from grafted and non grafted sites for histological, histochemical and histomorphometric assessment. There was no evidence of inflammation or adverse tissue reaction with either treatment. Defects grafted with ASCs-PRP showed a significantly higher result (p≤ 0.05), with a mean area % of spongy bone and compact bone of (64.96±5.37 and 837.62±24.95), compared to ASCs alone (47.65±1.43 and 661.92±12.65) and without grafting (33.55± 1.74 and 290.85±7.27) respectively. The area % of lamellated bone increased significantly reaching its highest level in group A followed by group B. Also a significant increase in area % of neutral mucopolysaccharides and calcified reactivity of Masson|s Trichrome stain in groups A and B compared to group C was obtained. Our results suggest that, the addition of PRP to ASCs enhances bone formation after 3 months and may be clinically effective in accelerating postsurgical healing in both periodontal and maxillofacial surgical applications.

Effect of implant surface properties on peri-implant bone healing: a histological and histomorphometric study in dogs

The present study aimed to evaluate and compare two types of implants, i.e. grit-blasted and acid-etched implants (SLActive(®)) with nano-meter-scale hydroxyapatite surface-modified implants (NanoTite™). For histological and histomorphometrical evaluation, 22 SLActive(®) and 22 Nanotite™ implants were inserted in eleven Beagle dogs. The animals were divided into three groups of healing (A: 2 weeks; B: 4 weeks and C: 8 weeks). Two, 4 and 8 weeks after implantation, the animals were sacrificed and bone-to-implant contact (BIC %), first implant-bone contact (1st BIC) as well as amount of bone (BV) were assessed. For SLActive(®) and Nanotite™ implants, BIC% increased significantly over time. No statistically significant differences in BIC% were found between SLActive(®) and Nanotite™ at all the respective implantation times. Moreover, for the different healing periods, no significant differences for BV between SLActive(®) and Nanotite™ implants were found. The present study showed that SLActive(®) and NanoTite™ implants induce a similar bone response after implantation for 2, 4 and 8 weeks in a non-submerged position in the mandible of dogs.

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

To evaluate the influence of magnesium-enriched hydroxyapatite (MHA) (SintLife(®)) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. 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. 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. 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.

Flap vs. “flapless” surgical approach at immediate implants: a histomorphometric study in dogs

To compare the remodeling of the alveolar process at implants installed immediately into extraction sockets by applying a flap or a "flapless" surgical approach in a dog model. Implants were installed immediately into the distal alveoli of the second mandibular premolars of six Labrador dogs. In one side of the mandible, a full-thickness mucoperiosteal flap was elevated (control site), while contra-laterally, the mucosa was gently dislocated, but not elevated (test site) to disclose the alveolar crest. After 4 months of healing, the animals were sacrificed, ground sections were obtained and a histomorphometric analysis was performed. After 4 months of healing, all implants were integrated (n=6). Both at the test and at the control sites, bone resorption occurred with similar outcomes. The buccal bony crest resorption was 1.7 and 1.5 mm at the control and the test sites, respectively. "Flapless" implant placement into extraction sockets did not result in the prevention of alveolar bone resorption and did not affect the dimensional changes of the alveolar process following tooth extraction when compared with the usual placement of implants raising mucoperiosteal flaps.