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This study delves into the osteogenic potential of a calcium-ion modified titanium implant surface, unicCa, employing state-of-the-art proteomics techniques both in vitro (utilizing osteoblasts and macrophage cell cultures) and in vivo (in a rabbit condyle model). When human osteoblasts (Hobs) were cultured on unicCa surfaces, they displayed a marked improvement in cell adhesion and differentiation compared to their unmodified counterparts. The proteomic analysis also revealed enrichment in functions associated with cell migration, adhesion, extracellular matrix organization, and proliferation. The analysis also underscored the involvement of key signalling pathways such as PI3K-Akt and mTOR. In the presence of macrophages, unicCa initially exhibited improvement in immune-related functions and calcium channel activities at the outset (1 day), gradually tapering off over time (3 days). Following a 5-day implantation in rabbits, unicCa demonstrated distinctive protein expression profiles compared to unmodified surfaces. The proteomic analysis highlighted shifts in adhesion, immune response, and bone healing-related proteins. unicCa appeared to influence the coagulation cascade and immune regulatory proteins within the implant site. In summary, this study provides a comprehensive proteomic analysis of the unicCa surface, drawing correlations between in vitro and in vivo results. It emphasizes the considerable potential of unicCa surfaces in enhancing osteogenic behavior and immunomodulation. These findings significantly contribute to our understanding of the intricate molecular mechanisms governing the interplay between biomaterials and bone cells, thereby facilitating the development of improved implant surfaces for applications in bone tissue engineering.

Aim: To investigate the healing after heterotopic mucosa transpositioning at dental implants and teeth., Materials and Methods: One hemimandible per dog (n = 4) was allocated to receive 3 implants (test), whereby 3 premolars on the contralateral side served as controls. After osseointegration, a Z-plasty was performed on the buccal aspect of the test and control sites to heterotopically move the zone of keratinized tissue (KT) into a region with non-keratinized tissue (nKT) and vice versa. Clinical measurements were performed before (T0) and at 12 weeks following heterotopic transposition (T1). Thereafter, specimens were processed for histological analysis., Results: Clinical measurements revealed that at T1, a band of KT was reestablished at teeth (mean: 2.944 ± 1.866 mm), whereas at implants, the transpositioned nKT resulted in a mucosa without any signs of keratinization (mean: 0 mm; p < .0001). At implant sites, the probing attachment level loss was more pronounced compared to tooth sites (-1.667 ± 1.195 mm and -1.028 ± 0.878 mm, respectively; p = .0076). Histologically, the transpositioned nKT, was accompanied by the formation of KT at the tooth but not at implant sites. The supracrestal soft tissues were statistically significantly higher at tooth compared to implant sites (2.978 ± 0.483 mm and 2.497 ± 0.455 mm, p = .0083). The transpositioned KT remained mostly unaltered in its morphological characteristics., Conclusions: The findings of this study indicate that: (a) transpositioned KT may retain its morphological characteristics; and (b) transpositioned nKM was accompanied by the formation of KT at the tooth but not at implant sites., (© 2023 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Aim: To investigate the spontaneous regeneration of the implanto-mucosal and dento-gingival unit after complete removal of keratinized tissue (KT)., Materials and Methods: One hemi-mandible per dog (n = 4) was allocated to receive three dental implants (test sites, premolar region), whereas three premolars on the contralateral side were controls. After osseointegration, the entire KT (buccal + lingual) was surgically excised on all test and control sites, leaving the bone exposed. Clinical measurements were performed before excision (T 0 ) and after 12 weeks (T 1 ). Following healing, the animals were euthanized, and the specimens were histologically processed. Descriptive statistical analyses were performed., Results: Clinical measurements revealed that at T 1 , on all teeth, a band of KT was spontaneously regenerated (mean width: 2.60 ± 0.66 mm), whereas on implants, KT was detected only occasionally at mesial or distal but not at buccal sites (mean total: 0.35 ± 0.53 mm; p < .0001). Histologically, spontaneous regeneration of the dento-gingival unit was evident, displaying masticatory mucosa. At the implant sites, on the other hand, the implanto-mucosal unit was characterized by a non-keratinized epithelium and elastic fibres, indicating the characteristics encountered in alveolar mucosa., Conclusion: After excision of KT at implant sites, the spontaneous regeneration of the soft tissue is characterized by a non-keratinized epithelium typical for alveolar mucosa, while at tooth sites the spontaneous regeneration was characterized by soft tissue resembling gingiva., (© 2023 The Authors. Journal of Clinical Periodontology published by John Wiley & Sons Ltd.)

Objectives: To evaluate the sequential osseointegration of a novel titanium implant system based on a 3D printing technology in comparison with conventional titanium implants., Material and Methods: Two novel titanium implants based on 3D printing were tested in the mandible of eight Beagle dogs. As a control, two different commercially available titanium implants were used. The implants were staged to accommodate healing periods of 2 and 6 weeks. The primary outcome variable was bone-to-implant contact (BIC) in non-decalcified tissue sections and micro-CT analysis., Results: Histomorphometrically, the proportions of tissues adjacent to the implant surfaces were similar for all implants, whereas the BIC percentage of new mineralized bone was greater for the control implants after both 2 and 6 weeks (p < .05). Micro-CT analysis revealed increasing osseous volume and BIC from 2 to 6 weeks. In contrast to the histomorphometry, the BIC evaluation with the micro-CT data revealed a significantly higher BIC for the two test implants compared with controls (p < .001). The analysis of the total implant surface area disclosed a value that was approximately double as high for the test compared to the control implants., Conclusions: The novel titanium implant system based on 3D printing yielded values for osseointegration that were adequate and satisfactory. The higher percentage of new mineralized bone in the control implants is explained by the fact of a completely different three-dimensional surface area., (© 2023 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Objective: To histologically evaluate soft tissue healing following immediately placed one-piece zirconia implant and grafting a xenograft into the buccal gap., Materials and Methods: The third and fourth premolars (PM3 and PM4) in both quadrants of the mandible of nine dogs were used for this experiment. Those teeth were removed flapless and implants were placed into the distal sockets in a lingual position. In one side of the jaw, the gap between the implant and the socket walls was grafted (test) while no grafting was performed in the contralateral side (control), randomly selected. After 6 months of healing, biopsies were obtained and prepared for histological analysis. Soft tissue measures like supracrestal soft tissue height (STH), length of barrier epithelium (BE), and connective tissue (CTC) were measured at buccal and lingual surfaces., Results: The marginal mucosa was in a coronal position on the test side compared with the control side. At the buccal surface, the BE was longer in the test side than in the control side, while the CTC was longer in the control side than in the test side. For the STH (BE + CTC), the difference between the groups was not statistically significant., Conclusion: The placement of a xenograft into the gap between a 1-piece zirconia implant and the buccal wall in dogs modified the process of soft tissue healing, providing less soft tissue recession. The gap size seems to have a modifying effect on the application of this protocol., (© 2023 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Aim: To compare clinical and histological keratinized tissue formation around teeth and implants following coronal repositioning of alveolar mucosa with or without a connective tissue graft (CTG)., Materials and Methods: In nine beagle dogs, the third and fourth premolars (P3 and P4) were extracted from one side of the maxilla. Three months after the tooth extraction, a full-thickness buccal flap was raised and two implants were placed in those healed areas. On the contra-lateral side, a buccal flap was also raised at the P3 and P4 areas. Before suturing, the dogs were randomly assigned to three study groups (control, non-keratinized tissue [NKT], and non-keratinized tissue CTG [NKT-CTG]). In the control group, the buccal flaps were re-positioned around the teeth (P3 and P4) on one side, and implants on the other side, presenting an adequate band of keratinized tissue (KT). For the NKT and NKT-CTG groups, this buccal KT was then excised. In the NKT group, the buccal flap without KT (alveolar mucosa) was re-positioned around the teeth and implants. In the NKT-CTG group, a CTG taken from the excised KT was sutured to the buccal alveolar mucosa and then both were re-positioned around the teeth and implants. The clinical height of the KT was measured at baseline and at 1, 2, and 3 months of healing. The animals were sacrificed at 3 months, at which point the KT height was measured histologically., Results: The control group presented normal healing with a band of KT surrounding the teeth and implants. In the NKT and NKT-CTG groups, a new KT band approximately 2 mm in height (measured clinically and histologically) spontaneously formed around all teeth, regardless of whether a CTG had been placed. In the NKT implant group, no new KT was observed (clinically or histologically). Around the implants in the NKT-CTG group, a small amount of KT was formed in just two of the six implants., Conclusions: After surgical excision of KT, spontaneous KT is formed around teeth but not around implants, regardless of the placement of a CTG., (© 2022 The Authors. Journal of Clinical Periodontology published by John Wiley & Sons Ltd.)

Objectives: To develop a new preclinical model to study early implant loss, where local infection conditions would impair the implant osseointegration., Materials and Methods: Forty-eight smooth, 2.9-mm diameter experimental implants were placed in the mandible of 8 beagle dogs (3 in each side). In half of the animals (test group, n = 24 implants), the implants received ligatures around the implant-abutment connection. In the other half, no ligatures were placed (control group, n = 24 implants). Four weeks later, implants were extracted in a flapless approach and standard 3.3-mm diameter SLActive implants were placed into the same osteotomy site without any further drilling. Eight weeks after the second implantation, animals were sacrificed and analyzed in terms of implant survival., Results: After 8 weeks of healing, 4 implants were lost in the control group and 14 in the test group. This corresponded to a 17.4% of early implant loss in the control group and 58.3% in the test. Most of the early failures occurred within the first 5 weeks of healing., Conclusions: Implants placed in a pre-contaminated site present higher early loss than those placed in a non-contaminated site. This study represents a valid and robust preclinical model to study mechanisms and reduction of early implant loss as new technologies become available., Clinical Relevance: Scientific rationale for the study: There is lack of animal models to study early implant loss. Thus, a proposal of a new model is presented. With the validation of this model, new technologies can be implemented to prevent early implant loss., (© 2022. The Author(s).)

Objectives: The purpose of this experimental in vivo investigation was to evaluate the influence of modifying the implant surface by adding a monolayer of multi-phosphonate molecules on the de novo bone formation and osseointegration., Material and Methods: The study was designed as an animal preclinical trial with intra-animal control and two healing periods, 2 and 8 weeks, to compare implants with an identical macro-design but with two different surfaces. Eight female Beagle dogs participated in the study. Control implants had a moderately rough surface combining sandblasting and acid etching; test implants had an additional monophosphonate layer covalently bonded to titanium. Histologic and radiographic (micro-CT) outcome variables were evaluated., Results: The first bone-to-implant contact (fBIC) was located more coronally for the test implants at the first (0.065 mm (95% CI = -0.82, 0.60)) and second healing milestones (0.17 mm (95% CI = -0.9, 0.55)). Most coronal BIC of the test implants displayed a higher percentage of osseointegration, +6.33% and +13.38% after 2 and 8 weeks, respectively; however, the differences were not statistically significant. The micro-CT examination did not show any BIC difference., Conclusions: The monophosphonate layer coating demonstrated clinical, histological, and radiographic results similar to the control surface., (© 2021 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Objective: To evaluate the hard tissue volumetric and soft tissue contour linear changes in implants with two different implant surface characteristics after a ligature-induced peri-implantitis., Material and Methods: In eight beagle dogs, implants with the same size and diameter but distinct surface characteristics were placed in the healed mandibular sites. Test implants had an external monolayer of multi-phosphonate molecules (B+), while control implants were identical but without the phosphonate-rich surface. Once the implants were osseointegrated, oral hygiene was interrupted and peri-implantitis was induced by placing subgingival ligatures. After 16 weeks, the ligatures were removed and peri-implantitis progressed spontaneously. Bone to implant contact (BIC) and bone loss (BL) were assessed three-dimensionally with Micro-Ct (μCT). Dental casts were optically scanned and the obtained digitalized standard tessellation language (STL) images were used to assess the soft tissue vertical and horizontal contour linear changes., Results: Reduction of the three-dimensional BIC percentage during the induction and progression phases of the experimental peri-implantitis was similar for both the experimental and control implants, without statistically significant differences between them. Soft tissue analysis revealed for both implant groups an increase in horizontal dimension after the induction of peri-implantitis, followed by a decrease after the spontaneous progression period. In the vertical dimension, a soft tissue dehiscence was observed in both groups, being more pronounced at the buccal aspect., Conclusions: The added phosphonate-rich surface did not provide a more resistant environment against experimental peri-implantitis, when assessed by the changes in bone volume and soft tissue contours., Clinical Relevance: Ligature-induced peri-implantitis is a validated model to study the tissue changes occurring during peri-implantitis. It was hypothesized that a stronger osseointegration mediated by the chemical bond of a phosphonate-rich implant surface would develop an environment more resistant to the inflammatory changes occurring after experimental peri-implantitis. These results, however, indicate that the hard and soft tissue destructive changes occurring at both the induction and progression phases of experimental peri-implantitis were not influenced by the quality of osseointegration.

Objectives: The aim was to evaluate the rate of bone loss progression during experimentally induced peri-implantitis using two different implant-abutment connections in implants with identical surface topography., Material and Methods: Forty-eight Regular Neck tissue-level SLA implants with a matching implant to abutment connection (TL) and 36 bone-level SLA implants with a switching platform implant to abutment connection (BL) were subjected to experimental peri-implantitis in two independent in vivo pre-clinical investigations. Experimental peri-implantitis was induced by means of silk ligatures during 3 months (induction phase), and followed for one extra month without ligatures (progression phase). Radiographic and clinical outcomes were evaluated longitudinally along both studies and subsequently compared between experiments., Results: During the induction phase, radiographic bone loss was significantly higher in implants with matched abutments compared with those with platform switching connections (2.65 ± 0.66 mm vs 0.84 ± 0.16 mm, respectively, p = 0.001). During the progression phase, both types of implant-abutment connection exhibited similar rates of radiographic bone loss. Similar outcomes were observed clinically., Conclusions: A platform switching connection resulted in a more benign development of peri-implantitis during the experimental induction phase of the disease. These differences, however, disappeared once the ligatures were removed (progression phase)., Clinical Relevance: Influence of the implant-abutment connection in peri-implantitis progression may be relevant when considering implant selection in the moment of placement. In this sense, platform switching abutment demonstrated less peri-implantitis development when compared to implant matching connection.

Objective: To histologically evaluate healing following grafting a xenogenous bone substitute in the buccal gap around the immediately placed one-piece zirconia implant., Materials and Methods: The third and fourth premolars (PM3 and PM4) in both quadrants of the mandible of nine Mongrel Hound dogs were used for this experiment. They have been removed, and the recipient sites were prepared. The implants were placed in a lingual position in the socket. In one side of the jaw, the gap between the implant and the socket walls was grafted (test) while no grafting was performed in the contralateral side (control), randomly selected. After 6 months of healing, biopsies were obtained and prepared for histological analysis. Vertical and horizontal measures were recorded in buccal and lingual surface., Results: The hard tissue was in a coronal position on the test side compared with the control side. The bone thickness around ZLA (zirconia large-grit sandblasted and acid-etched surface) level was larger on the test side. On the test side, the first bone-implant contact and bone crest, at the buccal aspect, were more coronal to ZLA in PM4 while in PM3 the same happened with the bone crest. The width of the buccal bone wall was larger in PM4 than in PM3 at the ZLA level and 1 mm apical to ZLA., Conclusion: The placement of a xenograft in the gap between 1-piece zirconia implant and the buccal wall in dogs modified the process of hard tissue healing, providing additional amount of hard tissue., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The goal of the present study was to evaluate human histologic healing of dental implants with a unique triangular neck design that is narrower than the implant body. Four patients in need of full-mouth reconstruction were recruited and received several implants to support a full-arch prosthesis. In each patient, two additional customized reduced-diameter implants were placed, designated to be harvested after 6 months of submerged healing. The eight harvested implants were all placed in healed edentulous maxillary or mandibular ridges. These implants were Ø 3.5 × 8 mm in size, and the final osteotomy drill allowed for the creation of a gap up to 0.2 mm in size between the coronal aspect of the triangular implant neck and the surrounding bone. At the end of the healing period, the implants were retrieved with the surrounding bone. Microcomputed tomography (μCT) was performed before processing the biopsy samples for undecalcified histologic exampination. Bone-to-implant contact (BIC) was measured from the μCT data and from buccolingual/buccopalatal and mesiodistal central histologic sections. All implant gaps were filled by mature remodeled bone. The mean BICs of the BL/BP and MD sections were 64.45% ± 6.86% and 65.39% ± 10.44%, respectively, with no statistically significant difference. The mean 360-degree 3D BIC measured all over the implant surface was 68.58% ± 3.76%. The difference between the BIC measured on the μCT and on the histologic sections was not statistically significant. The positive histologic results of the study confirmed the efficacy of this uniquely designed dental implant.

Objectives: The aim was to evaluate the degree of bone regeneration and re-osseointegration attained when combining a xenogeneic bone replacement graft plus rhBMP-2 and a collagen membrane in ligature-induced peri-implantitis osseous defects in dogs., Material and Methods: Thirty-six implants were placed in a total of 6 Beagle dogs, 3 months after tooth extraction. Once experimental peri-implantitis was induced, defects were randomly allocated into two treatment groups: in the test group guided bone regeneration was applied using de-proteinized bovine bone mineral with 10% collagen soak loaded with rhBMP2 covered with a natural collagen membrane. In the control group, the same scaffold and membrane were used but saline was used to soak the grafting material. After a period of 8 weeks of healing, a submerged environment clinical measurements were taken and histological outcomes were evaluated once the animals were euthanized. Histological bone defect regeneration (BR) was considered as the primary outcome variable, and dog was selected as the unit of analysis., Results: Partial defect resolution was observed in both treatment groups. The histometric analysis showed a higher degree of bone regeneration for the test group, although differences were not statistically significant, both in terms of histological bone gain and percentage of re-osseointegration., Conclusions: (a) The addition of rhBMP2 to a bovine xenograft/collagen vehicle carrier failed to provide a significant added value in terms of bone regeneration or re-osseointegration, (b) partial re-osseointegration of a previously contaminated surface was achieved, although (c) a complete defect resolution and re-osseointegration to the level previous to the induction of the disease failed to occur in any of the treatment groups., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: There is a lack of knowledge concerning the critical buccal bone thickness required for securing favorable functional and esthetic outcomes, conditioned to the dimensional changes after implant placement. A preclinical study was therefore carried out to identify the critical buccal bone wall thickness for minimizing bone resorption during physiologic and pathologic bone remodeling., Materials and Methods: A randomized, two-arm in vivo study in healthy beagle dogs was carried out. The first group of dogs was sacrificed 8 weeks after implant placement for histomorphometric examination of postsurgical resorption of the buccal bone wall. The second group of dogs was monitored during three ligature-induced peri-implantitis episodes and a spontaneous progression episode. Morphometric and clinical variables were defined for the study of physiologic and pathologic buccal and lingual bone loss., Results: Seventy-two implants were placed in healed mandibular ridges of 12 beagle dogs. Two groups were defined: 36 implants were placed in sites with a thin buccal bone wall (< 1.5 mm), and 36 were placed in sites with a thick buccal bone wall (≥ 1.5 mm). No implants failed during the study period. For the great majority of the histomorphometric parameters, a critical buccal bone wall thickness of at least 1.5 mm seemed to be essential for maintaining the buccal bone wall during physiologic and pathologic bone resorption. Suppuration (+) and mucosal recession (-) were more often associated with implants placed in sites with a thin buccal bone wall., Conclusion: A critical buccal bone wall thickness of 1.5 mm at implant placement is advised, since a thicker peri-implant buccal bone wall (> 1.5 mm) is exposed to significantly less physiologic and pathologic bone loss compared with a thinner buccal bone wall (< 1.5 mm).

Objectives: To study the hard and soft tissue volume after placing immediate (IMI) or delayed implants (DLI) with a triangular coronal macro-design (Test/T) or a conventional cylindrical design (Control/C)., Material and Methods: T/C implants were inserted in healed ridges or in fresh extraction sockets of eight beagle dogs. Biopsies were processed for Micro-CT analysis and dental stone casts were optically scanned to obtain STL files revealing the soft tissue contours at 12 weeks. Image analysis software was utilized to match common landmarks superimposing the two sets of data. Three distinct volumes were calculated; buccal bone volume (B-BV), soft tissue volume below the implant shoulder (EC-STV), and the soft tissue volume above the implant shoulder (SC-STV). Using linear measurements, the soft tissue height (STH), the mucosal thickness (MT-IS), and the distance from the implant shoulder to the bone crest (I-BC) were assessed in the digital images and in conventional histology to assess the concordance, reproducibility, and reliability., Results: There were no significant differences between test and control implants regarding the buccal bone volume, although test implants had greater B-BV in all locations except for PM2. The soft tissue volume was similar at T/C implants. The surgical approach influenced the distribution of the total tissue volume. In the IMI, a low position of the bone crest was correlated with low values of B-BV, SC-STV, MT-IS, and STH. Linear measurements showed a high correlation between the histology and digital measurements and high inter and intra examiner agreement., Conclusion: The superimposition of Micro-CT/STL allowed the analysis of soft and hard tissue volumes. Reduction of the implant buccal aspect resulted in nonsignificant higher bone volume although similar soft tissue volume while the surgical approach influenced soft tissue response., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To analyse bone remodelling and peri-implant soft tissues around platform-switching implants with and without a machined collar placed at different levels in relation to bone crest., Material and Methods: All mandibular premolars and the first molars were extracted in five dogs. At 6 months, six implants with and without a machined neck (MACH and GBAE implants, respectively) were randomly inserted in each hemimandible positioning the implant-abutment interface in either a supracrestal (+1.5 mm), equicrestal, or subcrestal (-1.5 mm) position. After 6 months, animals were killed for histomorphometric analysis., Results: When net bone loss (primary outcome variable) was compared between MACH and GBAE groups, the multivariable regression analysis revealed no significant differences between implants inserted at the same vertical position. The dimensions of the peri-implant mucosa were greater in MACH implants compared with GBAE implants; however, these differences failed to reach statistical significance. Regarding the number of inflammatory cells and collagen fibre orientation, no statistically significant differences were found between MACH and GBAE groups., Conclusions: The surface treatment of the implant neck does not seem to have an influence on net bone loss, and there were no statistically significant differences in the peri-implant soft tissues between platform-switching implants with and without a machined neck., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To study the healing of peri-implant tissues around implants with a triangular coronal third (test) or cylindrical (control)., Materials and Methods: In eight beagle dogs, immediate and delayed implants were placed. Test and control implants were randomly assigned and the hard and soft tissue healing was evaluated with histology and micro-CT analysis at 4 and 12 weeks. The soft tissue contour changes were assessed by image analysis software., Results: When measured at the implant shoulder level, the buccal crestal width (primary outcome assessed in mm) attained similar values in test and control implants. More apically (3 mm) test implants had greater buccal crestal width in delayed and immediate sites. For vertical soft and hard tissue measurements, no significant differences were found between Test and Control. Micro-CT evaluation of the buccal volume of interest showed less volume of implant component in T implants in all sites, although bone volume was not significantly different between T/C. Soft tissue contours were similar around T/C implants., Conclusion: Triangular implants showed similar percentage of osseointegration, buccal bone volume and soft tissue contours, although attaining greater buccal crestal bone width. No differences were found in regard to soft tissue dimensions and the position of the first bone-to-implant contact., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To assess (i) bone regeneration around implants placed early in sites with or without ridge preservation and (ii) if the bone substitute material (DBBM-C) has to be removed at implant placement., Materials and Methods: In eight beagle dogs, three sites were randomly assigned to ridge preservation (DBBM-C plus collagen matrix (CMX)) (two sites; RP) or spontaneous healing (1 site; SH). Four weeks later, in one of the RP sites, dental implants were placed without removing the DBBM-C (RP1), whereas in RP2 and SH sites all non-integrated DBBM-C and/or granulation tissue were removed before implant placement and concomitant GBR. Histomorphometric outcomes were assessed at 4 and 12 weeks., Results: The median buccal fBIC (first bone-to-implant contact) was located more apical in groups RP1: 1.34 mm (0.09; 2.96) and RP2: 1.41 mm (0.54; 2.72) than in group SH: 0.79 mm (0.26; 1.50) (p = 0.452) at 4 weeks. At 12 weeks, median buccal fBIC values were for RP1: 0.88 mm (0.00; 2.33), for RP2: 0.16 mm (0.00; 1.33) and for SH: 0.00 mm (0.00; 0.98) (p = 0.362). BIC values increased over 12 weeks in all groups., Conclusions: Ridge preservation followed by early implant placement led to higher BIC values at 12 than at 4 weeks. There is no need to remove the biomaterial at implant placement to ensure osseointegration. No relevant differences were observed between the three groups for any outcome measure., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to evaluate the soft tissue histomorphometric composition around implant abutments comparing two different materials, titanium (Ti) and zirconia (ZrO 2 )., Material and Methods: Twelve implants were placed at bone level in the mandible of six beagle dogs (one in each side). At the same day of surgery one titanium abutment was screwed to the implant in one side (control group) and a zirconia abutment was screwed in the contralateral side. Nine months after implant/abutments placement, animals were sacrificed for histological analysis. Descriptive analysis was calculated for each variable and Wilcoxon test was applied to evaluate histomorphometric variables., Results: At the end of the study the soft tissue dimension at Ti and ZrO 2 were similar in all counterparts: biological width, the length of the barrier epithelium, length of the connective tissue, and the percentage of collagen fibers density. However, the percentage of blood vessels was higher for the Ti in comparison to ZrO 2 (5.11% ± 1.70 and 2.23% ± 0.98, respectively [P = 0.016])., Conclusions: Peri-implant soft tissue histomorphology composition was similar in implant abutments made of ZrO 2 and titanium after 9 months of healing., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to investigate clinical and soft/hard tissues histomorphological outcomes of a ceramic implant comparatively to a titanium implant in a minipig model., Material and Methods: Eighteen soft tissue level implants (9 Ceramic with ZLA(®) surface as test, and 9 titanium SLActive(®) as control, Institut Straumann, Basel, Switzerland) were randomly placed into the mandible of 6 minipigs (n = 6). Two months later, animals were sacrificed and block biopsies were obtained to assess histomorphological outcomes. Unadjusted paired comparisons, of both groups were performed using the Wilcoxon signed rank test. The Dunnett-Hsu test was used to adjust for multiple comparisons., Results: All implants showed excellent integration into bone and soft tissue. The fBIC (distance implant shoulder to most coronal implant contact) and BIC% (percentage bone-to-implant contact) were for both groups; test: 3.95 mm and 85.4%; control 3.97 mm and 84.3% respectively. No difference in peri-implant mucosa height was found, however, the sulcular epithelium was significantly shorter for the ZrO2 (mean: 0.76, 95%CI: 0.46-1.06) than for the Ti (mean: 1.40, 95%CI: 1.10-1.70) (p = 0.0090)., Conclusions: Within the limits of this pilot study, no difference was found between the ceramic implant with ZLA(®) surface and a titanium implant in terms of bone tissue integration. Furthermore, the epithelial attachment favoured this ceramic implant over titanium., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To test whether an equine bone substitute block used for guided bone regeneration (GBR) of peri-implant defects renders different results from bovine block or particulated bone substitutes regarding the dimensions of the augmented ridge and the amount of new bone., Material and Methods: Mandibular premolars and molars were extracted in eight dogs. After 4 months, four semi-saddle bone defects were created in each mandible and one titanium implant was inserted into every site. Bone augmentation by GBR was attempted using the following randomly assigned modalities: (i) particulated deproteinized bovine bone mineral (DBBM) + a collagen membrane (CM), (ii) block DBBM + CM, (iii) equine bone substitute block + CM, and (iv) empty controls. After 4 months, one central and two lateral sections of each site were prepared. Descriptive histological and histomorphometrical assessments were performed evaluating the augmented area (AA) within the former bone defect, the area of mineralized tissue (MT), non-mineralized tissue (NMT), and residual bone substitute (BS) within AA, the horizontal thicknesses of the augmented region (HTaugm ) and of the mucosa (HTmucosa )., Results: At the central sections, AA measured 11.2 ± 3.3 mm(2) for the equine block, 9.5 ± 2.6 mm(2) for DBBM block, 7.9 ± 4.8 mm(2) for particulated DBBM, and 2.4 ± 2.1 mm(2) for the empty control. All GBR groups rendered significantly higher values of AA in comparison with control (P ≤ 0.05). The differences in AA between GBR groups did not reach statistical significance (P > 0.05). The equine block rendered the highest values in HTaugm , although only the differences between equine block and control as well as equine block and DBBM block were statistically significant (P ≤ 0.05). With respect to HTmucosa , all GBR groups reached significantly higher values compared to control (P ≤ 0.05). The equine block revealed the most pronounced signs of graft degradation., Conclusions: Guided bone regeneration lead to higher ridge dimensions and thicker covering mucosa than empty controls. The equine block with CM resulted in the most favorable outcomes regarding the maintenance of ridge contour. There were no significant differences regarding amount of new bone between GBR treatments., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The aim was to test whether or not the marginal bone-level alterations of loaded zirconia implants are similar to the bone-level alterations of a grade 4 titanium one-piece dental implant., Materials and Methods: In six dogs, all premolars and the first molars were extracted in the mandible. Four months later, three zirconia implants (BPI, VC, ZD) and a control titanium one-piece (STM) implant were randomly placed in each hemimandible and left for transmucosal healing (baseline). Six months later, CAD/CAM crowns were cemented. Sacrifice was scheduled at 6-month postloading. Digital X-rays were taken at implant placement, crowns insertion, and sacrifice. Marginal bone-level alterations were calculated, and intra- and intergroup comparisons performed adjusted by confounding factors., Results: Implants were successfully placed. Until crown insertion, two implants were fractured (one VC, one ZD). At sacrifice, 5 more implants were (partly) fractured (one BPI, four ZD), and one lost osseointegration (VC). No decementation of crowns occurred. All implant systems demonstrated a statistically significant (except VC) loss of marginal bone between baseline and crown insertion ranging from 0.29 mm (VC; P = 0.116) to 0.80 mm (ZD; P = 0.013). The estimated marginal bone loss between baseline and 6 months of loading ranged between 0.19 mm (BPI) and 1.11 mm (VC), being statistically significant for STM and VC only (P < 0.05). The changes in marginal bone levels were statistically significantly different between zirconia implants and control implants (STM vs. BPI P = 0.007; vs. VC P = 0.001; vs. ZD P = 0.011)., Conclusions: Zirconia implants were more prone to fracture prior to and after loading with implant-supported crowns compared to titanium implants. Individual differences and variability in the extent of the bone-level changes during the 12-month study period were found between the different implant types and materials., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To evaluate the impact that immediate implant placement may have on bone remodelling in comparison with adjacent sockets left to heal spontaneously., Materials and Methods: In a beagle dog model (N = 16 dogs), mandibular premolars were extracted, and implants were placed in each distal socket (test) with the corresponding mesial site left to heal undisturbed (control). Healing was assessed measuring both the vertical distance between buccal and lingual crest (B'L') and the width of buccal and lingual walls at different levels. Five healing periods were evaluated. Differences between means for each variable and for each healing period between test and control were compared (Kruskal-Wallis test; Friedman test)., Results: At 2 and 8 weeks of healing, the B'L' distance revealed significant higher values at test compared to control sites, being this difference three times higher at the end of the study (P < 0.05). In the test group, the width of the crest was reduced between baseline (0.37 [0.04]) and 8 weeks healing (0.13 [0.64]), demonstrating a 62% reduction of the initial width. These differences were not observed in the control group., Conclusions: Immediate implant placement into fresh extraction sockets may jeopardize the vertical bone remodelling of the socket. Furthermore, a tendency towards greater buccal horizontal resorption was observed in the most coronal aspect of the buccal bone crest., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant., Materials and Methods: In six dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed. CAD/CAM crowns were cemented at 6 months. Six months later, animals were killed and histomorphometric analyses were performed, including: the level of the mucosal margin, the extent of the peri-implant mucosa, the marginal bone loss and the bone-to-implant contact (BIC). Means of outcomes variables were calculated together with their corresponding 95% confidence intervals., Results: In general, the mucosal margin was located coronally to the implant shoulder. The buccal peri-implant mucosa ranged between 2.64 ± 0.70 mm (VC) and 3.03 ± 1.71 mm (ZD) (for all median comparisons p > 0.05). The relative marginal bone loss ranged between 0.65 ± 0.61 mm (BPI) and 1.73 ± 1.68 mm (ZD) (buccal side), and between 0.55 ± 0.37 mm (VC) and 1.69 ± 1.56 mm (ZD) (lingual side) (p > 0.05). The mean BIC ranged between 78.6% ± 17.3% (ZD) and 87.9% ± 13.6% (STM) without statistically significant differences between the groups (p > 0.05)., Conclusions: One- and two-piece zirconia rendered similar peri-implant soft tissue dimensions and osseointegration compared to titanium implants that were placed at 6 months of loading. Zirconia implants, however, exhibited a relatively high fracture rate., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To investigate soft tissue histomorphology and quality around implants with a modified transgingival collar surface comparatively to a machined., Material and Methods: Twenty-seven Straumann Standard Tissue Level implants belonging to the following groups (nine of each group): Ti modSLA with machined collar (Ti-M), Ti modSLA with machined, acid-etched surface collar (Ti-modMA), and TiZr modSLA with machined, acid-etched surface collar (TiZr-modMA) were placed in the mandible of six minipigs. After 8 weeks of healing, buccal sections were obtained and processed for histological evaluation., Results: Histometric soft tissue outcomes were similar for the three types of implants. The percentage of connective tissue attached to implant surface and its length was longer at TiZr-modMA with respect to Ti-M implants. The number of inflammatory cells was slightly higher at the TiZr-modMA with respect to Ti-M implant. The percentage of area occupied by perpendicular collagen fibers was slightly higher for the modified surfaces in comparison with the machined., Conclusions: Modified implant collar surfaces at Ti and TiZr implants showed a soft tissue interface similar to machined. A tendency of increasing number of perpendicular collagen fibers and improved connective tissue contact was found at the modified implant surfaces., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The effect on the marginal peri-implant tissues following repeated platform switching abutment removal and subsequent reconnection was studied., Material and Methods: Six adult female Beagle dogs were selected, and Pm3 and Pm4 teeth, both left and right sides, were extracted and the sites healed for 3 months. At this time, 24 bone level (BL) (Straumann, Basel, Switzerland) Ø 3.3/8 mm implants were placed, 2 in each side on Pm3 and Pm4 regions. In one side (control group), 12 bone level conical Ø 3.6 mm healing abutments and, on the other side (test group), 12 Narrow CrossFit (NC) multibase abutments (Straumann) , Basel, Switzerland) were connected at time of implant surgery. On test group, all prosthetic procedures were carried out direct to multibase abutment without disconnecting it, where in the control group, the multibase abutment was connected/disconnected five times (at 6/8/10/12/14 weeks) during prosthetic procedures. Twelve fixed metal bridges were delivered 14 weeks after implant placement. A cleaning/control appointment was scheduled 6 months after implant placement. The animals were sacrificed at 9 months of the study. Clinical parameters and peri-apical x-rays were registered in every visit. Histomorphometric analysis was carried out for the 24 implants. The distance from multibase abutment shoulder to the first bone implant contact (S-BIC) was defined as the primary histomorphometric parameter., Results: Wilcoxon comparison paired test (n = 6) found no statistically significant differences (buccal P = 0.917; Lingual P = 0.463) between test and control groups both lingually and buccally for S-BIC distance. Only Pm3 buccal aBE-BC (distance from the apical end of the barrier epithelium to the first bone implant contact) (P = 0.046) parameter presented statistically significant differences between test and control groups. Control group presented 0.57 mm more recession than test group, being this difference statistically significant between the two groups (P < 0.001)., Conclusion: It can be conclude, within the limits of this animal study, that the connection/disconnection of platform switching abutments during prosthetic phase of implant treatment does not induce bone marginal absorption. Furthermore, it may present a negative influence in the buccal connective tissue attachment that becomes shorter anyway preventing marginal hard tissue resorption, especially in thin biotypes., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To study early bone healing of immediately loaded implants placed in fresh extraction sockets versus immediate implants without occlusal loading in the dog., Materials and Methods: A total of 48 implants were placed in the distal sockets of Pm3 and Pm4 in the lower jaw of 12 Beagle dogs immediately after tooth extraction. In the control group, no loading was applied. In the test group, an immediate loading restoration with occlusal contacts was performed. Dogs were sacrificed at 2, 4 and 8 weeks for histological analysis., Results: At the end of the study, there was a 100% implant and prosthesis survival. Similar results for test and control groups were observed for bone-to-implant contact (%) and peri-implant bone area. Inter-thread bone area tended to decrease in the control and increase in the test. With respect to ridge alterations, bone resorption was more pronounced on the buccal aspect and was observed in both groups., Conclusion: Immediate loading did not impair early stages of bone healing and crestal bone modelling at two-piece implants in fresh extraction sockets in the beagle dog; however, bone resorption occurred in all specimens in both groups., (© 2013 John Wiley & Sons A/S.)

Objective: Crohn's disease is a chronic inflammatory process that has recently been associated with a higher risk of early implant failure. Herein we provide information on the impact of colitis on peri-implant bone formation using preclinical models of chemically induced colitis., Methods: Colitis was induced by intrarectal instillation of 2,4,6-trinitro-benzene-sulfonic-acid (TNBS). Colitis was also induced by feeding rats dextran-sodium-sulfate (DSS) in drinking water. One week after disease induction, titanium miniscrews were inserted into the tibia. Four weeks after implantation, peri-implant bone volume per tissue volume (BV/TV) and bone-to-implant contacts (BIC) were determined by histomorphometric analysis., Results: Cortical histomorphometric parameters were similar in the control (n = 10), DSS (n = 10) and TNBS (n = 8) groups. Cortical BV/TV was 92.2 ± 3.7%, 92.0 ± 3.0% and 92.6 ± 2.7%. Cortical BIC was 81.3 ± 8.8%, 83.2 ± 8.4% and 84.0 ± 7.0%, respectively. No significant differences were observed when comparing the medullary BV/TV and BIC (19.5 ± 6.4%, 16.2 ± 5.6% and 15.4 ± 9.0%) and (48.8 ± 12.9%, 49.2 ± 6.2 and 41.9 ± 11.7%), respectively. Successful induction of colitis was confirmed by loss of body weight and colon morphology., Conclusions: The results suggest bone regeneration around implants is not impaired in chemically induced colitis models. Considering that Crohn's disease can affect any part of the gastrointestinal tract including the mouth, our model only partially reflects the clinical situation., (© 2012 John Wiley & Sons A/S.)

Background: Growth hormone (GH) and melatonin belong to the group of growth factors. These substances have been proposed to improve and accelerate osseous healing using topical applications., Purpose: The aim of this study was to evaluate the effect of the topical administration of GH and melatonin on osseointegration of dental implants in Beagle dogs 2, 5, and 8 weeks after their insertion., Materials and Methods: Twelve adult Beagle dogs and 48 implants were used in the study. The maxillary and mandibular premolars and molars were extracted. Each mandible received cylindrical screw implants of 3.25 mm in diameter and 10 mm in length. Prior to implanting, 4 IU of recombinant human GH and 1.2 mg of lyophilized powdered melatonin was applied to one osteotomy at each side of the mandible. None was applied at the control sites. The implants were retrieved at 2, 5, and 8 weeks for light microscopic examination, energy-dispersive x-ray microanalysis, and histomorphometric measurements in ground sections., Results: At week 2, BIC was significantly higher in the melatonin-growth hormone group than in the implant control one (34.20 vs 25.05%; p = .010). The M-GH group also increased significantly the peri-implant bone area (64.72 vs 53.20%; p = .038) and interthread bone area (35.62 vs 25.08%; p = .02). At weeks 5 and 8, BIC and bone density around implants were similar to both groups. Significant differences were detected in bone neoformation at 8 weeks in ML-GH group (9.04 vs 7.53%; p = .05). Regarding the mineral composition, in ML-GH group increments in concentrations of phosphorus (10.70 vs 10.34; p = .013) were observed at 2 weeks and of magnesium (0.29 vs 0.25; p = .019) 5 weeks after implantation., Conclusion: The present study confirms that GH and melatonin synergistically enhance new bone formation around titanium implants in early stages of healing., (© 2009 Wiley Periodicals, Inc.)

Objective: The aim of the present study was to evaluate the peri-implant soft tissue dimensions in flapless immediate implants with and without immediate loading., Material and Methods: This study was carried out on six beagle dogs. Four implants were placed (two per side) immediately after tooth extraction (third and fourth premolars). Flapless immediate implant placement was performed in one hemimandible (control). The same procedure was performed in the contralateral side and immediate prosthesis was connected (test). After 3 months of healing, the dogs were sacrificed., Results: None of the implants and prosthesis were lost. Barrier epithelium in the loaded group was 2.51 mm at the buccal and 2.34 mm at the lingual aspect. In the no loaded group, the results were similar, 2.54 and 2.2 mm at the buccal and lingual side, respectively. Connective tissue in the loaded group was 1.38 mm at the buccal and 0.65 mm at the lingual aspect, and in the no loaded group 1.48 mm at the buccal and 0.53 mm at the lingual side. Biological width dimensions were 3.9 mm at the buccal and 2.95 mm at the lingual aspect for the loaded group, and 4.01 and 2.64 mm at the buccal and lingual aspect for the no loaded group., Conclusions: The results of the present study suggested that soft tissues dimensions around immediate implants with immediate loading were similar to immediate implants without loading., (© 2011 John Wiley & Sons A/S.)

Objective: To assess the effect of immediate loading on ridge alterations following implants placed into fresh extraction sockets in a dog model., Material and Methods: Six Beagle dogs were used. Four implants were placed into post-extraction sockets in the lower jaw immediately after the removal of premolars 3 and 4. In the control side, two implants remained without occlusal loading, and in the test side, they received an immediate prosthesis with occlusal contacts (involving implant sites). Extraction sockets without implants were used as a test in non-involved implant sites. Three months later, the dogs were sacrificed., Results: Vertical distance from implant shoulder to bone crest (BC) was similar for both groups. BC at the buccal aspect was located 3.66 mm apical to the shoulder in the test group and 4.11 mm in the control group. This difference was not statistically significant. Buccal bone resorption was more pronounced in the premolar 3 area than in the premolar 4 area. In edentulous sites, the buccal bone crest was located 0.97 mm apical to the lingual counterpart., Conclusion: Immediate implant placement with or without immediate loading does not prevent the amount of bone resorption that occurs following tooth extraction without immediate implant placement., (© 2011 John Wiley & Sons A/S.)

Objectives: To evaluate whether different implants placed immediately upon tooth extraction may affect the dimension and composition of the peri-implant soft tissues., Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of 3P3 and 4P4. Four commercially available implant systems were evaluated: 3i Osseotite Certain straight; Astra MicroThread-OsseoSpeed; Thommen SPI Element; and Straumann ITI standard. Each animal provided four test implant sites. All animals were sacrificed 6 weeks after implant placement, providing specimens for the evaluation of the soft tissue dimensions by histometric analysis., Results: The biological width at 6 weeks after implant placement consisted of a junctional epithelium measuring between 2 and 2.7 mm and a connective tissue component between 1 and 1.8 mm with no statistical differences among the four implant systems., Conclusion: This study failed to demonstrate differences in the soft tissue healing outcome when placing four different implant systems into fresh extraction sockets. Nevertheless, the length of the epithelium achieved with the four implant systems is longer than what has been reported when placing implants in healed-ridge experimental models.

Objective: To assess the marginal soft tissue healing process after flap or flapless surgery in immediate implant placement in a dog model., Material and Methods: This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control) and flapless on the other (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis., Results: Ten implants were placed in each group. Two failed (one of each group). The length of the junctional epithelium in the flapless group was 2.54 mm (buccal) and 2.11 mm (lingual). In the flap group, the results were very similar: 2.59 mm (buccal) and 2.07 mm (lingual), with no significant differences observed between the groups. The length of the connective tissue in the flapless group was 0.68 mm (buccal) and 0.54 mm (lingual), and 1.09 mm at the buccal and 0.91 mm at the lingual aspect in the flap group, with no significant differences between groups. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was significant between both groups (3.02 mm-flapless and 3.69 mm flap group). However, this difference was mostly due to the Pm3 group (flapless: 2.95/flap: 3.76) because no difference could be detected in the Pm4 group. Both groups showed minimal recession, with no significant differences between groups (flapless group - 0.6 mm buccal and 0.42 mm lingual; flap group - 0.67 and 0.13 mm)., Conclusion: The clinical evaluation of immediate implant placement after 3 months of healing indicated that buccal soft tissue retraction was lower in the flapless group than in the flap group, without significant differences. The mean values of the biological width longitudinal dimension at the buccal aspect were higher in the flap group than in the flapless group, this difference being mostly due to the Pm3, probably because of a thinner biotype in this region.

Purpose: The aim of this study was to evaluate the effect of the topical application of growth hormone on the osseointegration of dental implants in beagle dogs 14 days after placement., Materials and Methods: Maxillary and mandibular premolars and molars were extracted from 12 beagle dogs. Two months later, each mandible received cylindric screw-type implants of 3.25 mm in diameter and 10 mm in length. The implants were randomly assigned to the mesial and distal sites on each side of the mandible. Prior to implantation, lyophilized powdered growth hormone was applied to one osteotomy on each side of the mandible. No growth hormone was applied at the control sites. Eight histologic sections per implant were obtained for histomorphometric analysis., Results: After a 2-week treatment period, the growth hormone-treated sites showed significant (P < .0001) increases in the perimeter of bone that was in direct contact with the treated implants (40.19% +/- 2.51%), total peri-implant area (P < .001) (69.57% +/- 3.53%), and new bone formation (P < .0001) (35.18% +/- 0.31%), in comparison to control implants (25.05% +/- 2.43%, 53.40% +/- 4.58%, and 28.65% +/- 1.92%, respectively). There was no significant increase in interthread bone in growth hormone-treated implants (27.92% +/- 3.31%) in comparison to control implants (25.08% +/- 3.47%) (P > .05)., Conclusion: Topical application of growth hormone may act as a bone stimulant in the placement of endosseous dental implants.

The aim of this study was to evaluate the effect of the topical application of melatonin on osteointegration of dental implants in Beagle dogs 14 days after their insertion. In preparation for subsequent insertion of dental implants, upper and lower premolars and molars were extracted from 12 Beagle dogs. Each mandible received cylindrical screw implants of 3.25 mm in diameter and 10 mm in length. The implants were randomly assigned to the mesial and distal sites on each side of the mandible. Prior to implanting, 1.2 mg lyophylized powdered melatonin was applied to one bone hole at each side of the mandible. None was applied at the control sites. Eight histological sections per implant were obtained for histomorphometric studies. After a 2-wk treatment period, melatonin significantly increased the perimeter of bone that was in direct contact with the treated implants (P < 0.0001), bone density (P < 0.0001), new bone formation (P < 0.0001) and inter-thread bone (P < 0.05) in comparison with control implants. Topical application of melatonin may act as a biomimetic agent in the placement of endo-osseous dental implants.

Objective: To assess the healing process after flap or flapless surgery in immediate implant placement., Material and Methods: This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control), and flapless on the contrary (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis., Results: Ten implants were placed in each group. Two failed (one of each group). The percentage of bone-implant contact was very similar in both groups: 64.8% and 65.1% for the flap and the flapless group, respectively. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was statistically significant between both groups (3.02 mm. flapless and 3.69 mm. flap group). The mean first bone-implant contact at the buccal aspect was located in relation to the sand-blasted and acid-etched level at 0.82 mm for the flapless group and 1.33 mm for the flap group. This difference was not statistically significant., Conclusion: Flapless immediate implant surgery produces a significant reduction in the vestibular biologic width and a minor reduction in buccal bone plate resorption.

Objectives To study early soft tissue healing of immediately placed implants with or without immediate loading in the dog. Material and methods Forty-eight implants were placed in the distal sockets of Pm3 and Pm4 in the lower jaw of 12 beagle dogs immediately after tooth extraction. In the control group, no loading was applied. In the test group, an immediate loading restoration with occlusal contacts was performed. Dogs were sacrificed at 2, 4, and 8 weeks for histological analysis. Results At the end of the study, there was a 100% implant and prosthesis survival. The biological width dimension was similar in both groups at all the studied healing periods. This dimension tended to decrease from week 2 to 8 in both groups, on both the buccal and lingual side. The barrier epithelium tended to stop at the implant-abutment interface in both groups and also decreased in length from week 2 to 8, on the buccal and the lingual side. Soft tissue recession remained low and occurred mainly in the test group. Conclusions The characteristics, dimension, and healing pattern of the peri-implant soft tissues were similar around immediate implants with or without immediate loading. [ABSTRACT FROM AUTHOR]