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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. [ABSTRACT FROM AUTHOR]

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.)

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 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 assess volumetric and linear changes following ridge preservation (RP) or spontaneous healing plus early implant placement with or without simultaneous guided bone regeneration (GBR)., Materials and Methods: In eight adult beagle dogs, the mesial roots of the mandibular P3, P4 and M1 were extracted. Sites were randomized to either ridge preservation (RP) or spontaneous healing (SH). Four weeks later dental implants were placed either with (RP2) or without removing non-integrated DBBM (RP1). In RP2 and SH sites, GBR was applied using a demineralized bovine bone mineral and a resorbable membrane. Impressions were taken postextraction (SH)/postridge preservation (RP1; RP2), before and after implant placement and after healing of 4 and 12 weeks. Casts were digitized to allow for superimposition and measurement of contour alterations., Results: Median ridge width reduction from postextraction (SH)/postridge preservation (RP1;RP2) to implant placement ranged from -13.9% (SH) to -19.7% (RP) (p > .05), whereas from implant placement to sacrifice, it was statistically significantly lower in group RP1 (-5.5%) compared to group SH (-23.4%; p = .0013) and group RP2 (-22.1%; p = .0026). Encompassing the entire study period, median ridge width changes ranged between -17.8% (SH), -24.8% (RP2) and -32.5% (RP1) (p > .05)., Conclusions: Irrespective of the treatment modality and the healing period, part of the ridge contour was lost. Early implant placement after ridge preservation without additional GBR resulted in a more stable ridge contour after implant placement compared to controls., (© 2017 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.)

Aim: This study assessed the associations of pre-diabetes and insulin resistance with bleeding on probing (BOP) and periodontitis among adults., Materials and Methods: We included 1191 Hispanic adults aged 40-65 years, free of diabetes, enrolled in San Juan Overweight Adults Longitudinal Study. Pre-diabetes was defined as impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or impaired glycated haemoglobin. Impaired one-hour plasma glucose (1hPG) was defined as levels >155 mg/dl. Insulin resistance was defined using the study population-specific 75th percentile (HOMA-IR ≥ 3.13). High BOP was defined as percentage of teeth with bleeding ≥30%. Periodontitis was defined according to the CDC/AAP definition., Results: After multivariable adjustment for age, gender, education, smoking status, alcohol consumption, physical activity, obesity, HDL-C, and plaque index, pre-diabetes with and without 1hPG, IFG, impaired 1hPG, IGT, and HOMA-IR were significantly associated with high BOP; pre-diabetes, IFG, and impaired 1hPG were significantly associated with severe periodontitis. Most of these associations remained significant when the analyses were restricted to non-smokers., Conclusions: This study suggests associations between pre-diabetes and insulin resistance with BOP and periodontitis. Given the high prevalence of impaired glucose metabolism and periodontitis, the assessment of the temporal sequence of these associations is of utmost importance., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The aim of the present study was to evaluate the effect of a titanium brush and chemical agents following surgical treatment of experimental peri-implantitis., Material and Methods: Six implants were installed in the mandible of eight beagle dogs (unit of analysis) 3 months after tooth extraction. Experimental peri-implantitis was induced 3 months later. The defects were randomly allocated in three treatment groups: (a) TiBrush(™)  + sodium hypochlorite + chlorhexidine (TBH), (b) TiBrush(™)  + chlorhexidine (TB), (c) an ultrasonic device + chlorhexidine (US). The distal implant in each hemimandible was used as control, and no treatment was done. Clinical and histological measurements were performed after 3 months of healing., Results: All treatment procedures resulted in statistically significant improvements of all clinical parameters. Histomorphometrical analysis revealed no statistically significant differences between treatment groups in terms of woven bone height (primary outcome). However, there were differences between test and control groups in terms of inflammation, bone defect depth and bone refill without differences between TBH and TB groups., Conclusions: Resolution of peri-implantitis after access surgery and decontamination of peri-implant surfaces with TiBrush(™) with or without sodium hypochlorite is possible. However, the concomitant use of sodium hypochlorite has minor effect on treatment outcomes., (© 2016 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.)

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.)

Aim: To describe the early healing events in the alveolar socket during the first 8 weeks of spontaneous healing after tooth extraction., Materials and Methods: 16 adult beagle dogs were selected and five healing periods were analysed (4 h, 1 week, 2 weeks, 4 weeks, 8 weeks). Mandibular premolars were extracted and each socket corresponding to the mesial root was left to heal undisturbed. In each healing period, three animals were euthanatized, each providing four study sites. Healing was assessed by descriptive histology and by histometric analysis using as landmarks: the vertical distance between buccal and lingual crest (B'L') and the width of buccal and lingual walls at three different levels. Differences between means for each variable for each healing period were compared (ANOVA; p < 0.05)., Results: B'L' at baseline was 0.45 (0.18) mm and decreased during the healing period to a final value of 0.18 (0.08) mm. The lingual width (Lw) remains almost unchanged while the buccal width (Bw) at 1 (Bw1) and 2 (Bw2) mm was reduced in about 40% of its initial value., Conclusions: Minor vertical bone reduction in both the buccal and lingual socket walls were observed. A marked horizontal reduction of the buccal bone wall was observed mostly in its coronal aspect., (© 2013 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.)

Objectives: The purpose of this investigation is to describe histologically the undisturbed healing of fresh extraction sockets when compared to immediate implant placement., Methods: In eight beagle dogs, after extraction of the 3P3 and 4P4, implants were inserted into the distal sockets of the premolars, while the mesial sockets were left to heal spontaneously. Each animal provided four socket sites (control) and four implant sites (test). After 6 weeks, animals were sacrificed and tissue blocks were dissected, prepared for ground sectioning., Results: The relative vertical buccal bone resorption in relation to the lingual bone was similar in both test and control groups. At immediate implant sites, however, the absolute buccal bone loss observed was 2.32 (SD 0.36) mm, what may indicate that while an apical shift of both the buccal and lingual bone crest occurred at the implant sites, this may not happen in naturally healing sockets., Conclusions: The results from this investigation showed that after tooth extraction the buccal socket wall underwent bone resorption at both test and control sites. This resorption appeared to be more pronounced at the implant sites, although the limitations of the histological evaluation method utilized preclude a definite conclusion., (© 2011 John Wiley & Sons A/S.)

Aim: To describe the histological and clinical outcomes of the use of a xenogeneic collagen matrix (CM) in combination with the coronally advanced flap (CAF) in the treatment of localized Miller class-I gingival recessions., Material and Methods: Gingival recession defects were surgically created on 12 minipigs. The defects were randomly treated with either the CAF procedure and the interposition of a CM (test) or the CAF alone (control). Clinical and histological outcomes at 1, 4 and 12 weeks were evaluated., Results: Histometrically, in the test group, there was a shorter junctional epithelial dimension [2.26 (SD 0.23) mm] compared with the control [2.79 (SD 0.77) mm]. On the contrary, the amount of newly formed cementum was larger in the test group [1.08 (SD 0.41) mm] than in the control group [0.75 (SD 0.25) mm], although the differences were not statistically significant., Conclusions: Both techniques rendered similar clinical outcomes, achieving complete root coverage at the end of the study. Nevertheless, the CM graft attained more tissue regeneration, characterized by a shorter epithelium and a larger new cementum formation. The use of a xenogeneic CM resulted in the incorporation of the xenograft within the adjacent host connective tissues in the absence of significant inflammation., (© 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.)

Objective: To assess the osseointegration process after flapless immediate implant placement with or without immediate loading., Material and Methods: This study was carried out on six beagle dogs. Four implants were placed in the lower jaw (two per side) in each dog immediately after tooth extraction (3rd and 4th premolars). Flapless immediate implant placement was performed in one hemimandible (control). The same procedure was carried out in the contra-lateral side and immediate prosthesis was connected with occlusal contacts (test). After 3 months of healing, the dogs were sacrificed for histomorphometric analysis., Results: Twelve implants were placed in each group. None of the implants and prosthesis was lost. The percentage of bone-to-implant contact (BIC %) was similar in both groups: 82.72% (test) and 76.96% (control). Differences were found neither in the inter-thread bone area (test: 83.45%, control: 80.65%) nor in peri-implant bone area (test: 94.37%, control: 94.81%)., Conclusion: In this animal model where the implants were well within the confines of the extraction socket, osseointegration following flapless immediate implant placement and loading can be achieved in the same manner as immediate placement without loading., (© 2010 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.