Enhancing guided bone regeneration with cross-linked collagen-conjugated xenogeneic bone blocks and membrane fixation: A preclinical in vivo study.

OBJECTIVE: To determine whether combining cross-linked (CL) collagen-integrated xenogeneic bone blocks stabilized with the fixation of resorbable collagen membranes (CM) can enhance guided bone regeneration (GBR) in the overaugmented calvarial defect model. MATERIALS AND METHODS: Four circular defects with a diameter of 8 mm were prepared in the calvarium of 13 rabbits. Defects were randomly assigned to receive one of the following treatments: (i) non-cross-linked (NCL) porcine-derived collagen-embedded bone block covered by a CM without fixation (NCL + unfix group); (ii) NCL bone block covered by CM with fixation using bone-tack (NCL + fix group); (iii) cross-linked (CL) porcine-derived collagen-embedded bone block covered by CM without fixation (CL + unfix group); and (iv) CL bone block covered by CM with fixation using bone-tack fixation (CL + fix group). The efficacy of GBR was assessed through histological and molecular analyses after 2 and 8 weeks. RESULTS: At 2 weeks, there were no significant differences in histologically measured areas of newly formed bone among the groups. At 8 weeks, however, the CL + fix group exhibited a larger area of new bone (5.08 ± 1.09 mm2, mean ± standard deviation) compared to the NCL + unfix (1.62 ± 0.42 mm2; p < .0083), NCL + fix (3.97 ± 1.39 mm2) and CL + unfix (2.55 ± 1.04 mm2) groups. Additionally, the expression levels of tumour necrosis factor-alpha, fibroblast growth factor-2, vascular endothelial growth factor, osteocalcin and calcitonin receptor were significantly higher in the CL + fix group compared to the other three groups (p < .0083). CONCLUSION: Cross-linked bone blocks stabilized with collagen membrane fixation can significantly enhance GBR.

Immediate loading of definitive restorations in partially edentulous patients requiring an implant-supported prosthesis: A scoping review.

STATEMENT OF PROBLEM: Interest is growing in immediately loading definitive implant-supported prostheses. However, it appears that implant protocols are evolving faster than their scientific validation. PURPOSE: The purpose of this scoping review was to identify the current trends, feasibility, and clinical outcomes of a specific clinical loading scenario (type A), where a single definitive implant-retained restoration is delivered within 3 days. The focus question was "In partially edentulous patients requiring an implant-retained prosthesis (population), is immediate loading with a definitive restoration (concept) a viable treatment option (context)?" MATERIAL AND METHODS: An electronic search was conducted in the PubMed, CENTRAL, Scopus, Embase, and Web of Science databases. Two authors independently reviewed the studies, screened titles and abstracts, and performed full-text analysis. Cross-reference checks within the bibliography of included studies, relevant reviews, and guideline were conducted. Bibliometric information and study details were extracted. RESULTS: The search identified 2568 titles after removing duplicates. Four studies involving 91 participant and 100 implant-retained restorations were included in this scoping review. The selected articles were a randomized controlled trial (RCT), a prospective clinical study, and the remaining 2 were case series. The follow-up periods investigated ranged from 6 to 26 months. All studies evaluated marginal bone loss as a primary outcome, and only 1 implant failure was reported. Patient-reported outcome measures were favorable, and no major biological or technical complications were reported in any study. CONCLUSIONS: Immediate loading with a definitive restoration within 3 days appears to be a suitable approach in specific clinical situations.

Immediate loading on two adjacent single dental implants with definitive nonsplinted restorations: A proof of concept in the posterior zone.

OBJECTIVES: To evaluate clinical, clinician- and patient-reported outcomes (PROs) of two adjacent single posterior implants immediately loaded with definitive single crowns up to 1 year. Ten patients in need of two adjacent posterior single implants were included. All implants were placed applying a fully digital workflow. Definitive screw-retained single zirconia crowns were delivered within 72 h after implant placement. Clinical parameters, patient- and clinician-reported outcomes were assessed up to 1 year of follow-up. CLINICAL CONSIDERATIONS: Clinical outcomes remained stable, with no implant failures or technical and biological complications throughout the observation period. Patient satisfaction was very high at baseline (crown delivery) and remained consistently high at 6 and 12 months of follow-up. Crown insertion 3 days after implant placement was rated as an easy procedure by clinicians. CONCLUSIONS: Two adjacent single implants with immediate definitive restorations (<72 h) in the posterior region appear to be a viable and easy treatment option to shorten the overall treatment time and potentially enhancing patient satisfaction. However, randomized controlled trials are needed to confirm the advantages of this treatment protocol over a delayed loading approach. CLINICAL SIGNIFICANCE: In selected cases, immediate implant loading with definitive restorations in the posterior region appears a valuable and straightforward option to shorten the overall treatment time.

Effects of implant placement timing and type of soft-tissue grafting on histological and histomorphometric outcomes in a preclinical canine model.

AIM: To determine the effects of implant timing and type of soft-tissue grafting on histological and histomorphometric outcomes in a preclinical model. MATERIALS AND METHODS: Four implant placement protocols were randomly applied at the mesial root sites of the third and fourth mandibular premolars in 10 mongrel dogs: immediate placement (group IP), early placement (group EP), delayed placement with/without alveolar ridge preservation (groups ARP and DP, respectively). A connective-tissue graft (CTG) or porcine-derived volume-stable collagen matrix (VCMX) was applied to enhance the ridge profile (simultaneously with implant placement in group IP and staged for others), resulting in five sites for each combination. All dogs were sacrificed 3 months after soft-tissue grafting. Histological and histomorphometric analyses were performed, and the data were analysed descriptively. RESULTS: CTG and VCMX were difficult to differentiate from the augmented area. The median total tissue thickness on the buccal aspect of the implant was largest in group IP/CTG (between 2.78 and 3.87 mm). The soft-tissue thickness was generally favourable with CTG at all implant placement timings. Within the DP groups, CTG yielded statistically significantly larger total and soft-tissue thickness than VCMX (p < .05). Among the groups with VCMX, group EP/VCMX showed the largest soft-tissue thickness at apical levels to the implant shoulder. CONCLUSIONS: CTG generally led to greater tissue thickness than VCMX.

The use of digital technologies in peri-implant soft tissue augmentation - A narrative review on planning, measurements, monitoring and aesthetics.

OBJECTIVE: To identify the different uses and modalities of digital technologies to diagnose, plan and monitor peri-implant soft tissue conditions and aesthetics. METHODS: A comprehensive narrative review of pertinent literature was conducted, critically appraising key digital technologies that may assist peri-implant soft tissue augmentation and assessment. An electronic search on four databases including studies published prior to 1st July 2023 was performed and supplemented by a manual search. RESULTS: Predominantly, tools such as cone beam computed tomography (CBCT), intraoral scanning (iOS), intraoral ultrasonography and digital spectrophotometry were commonly to assess and monitor peri-implant soft tissues. The main clinical and research applications included: (i) initial assessment of mucosal thickness, supra-crestal tissue height and keratinized mucosa width, (ii) evaluation of peri-implant soft tissue health and inflammation, (iii) monitoring profilometric changes and midfacial mucosal margin stability over time and (iv) aesthetic evaluation through colour assessment. While evidence for some digital tools may be limited, the integration of digital technologies into peri-implant soft tissue management holds great promise. These technologies offer improved precision, comfort and speed in assessment, benefiting both patients and clinicians. CONCLUSION: As digital technologies progress, their full potential in peri-implant soft tissue augmentation and their value will become more evident with ongoing research. Embracing these innovations and their potential benefits is recommended to ensure that during progress in implant dentistry, patient care is not hindered.

Impact of keratinized mucosa on implant-health related parameters: A 10-year prospective re-analysis study.

AIM: To investigate whether the lack of keratinized mucosa (KM) affects peri-implant health after 10 years of loading. MATERIALS AND METHODS: Data from 74 patients with 148 implants from two randomized controlled studies comparing different implant systems were included and analyzed. Clinical parameters including bleeding on probing (BOP), probing depth (PD), plaque index, marginal bone loss (MBL), and KM width (KMW) at buccal sites were collected at baseline (time of the final prosthesis insertion), 5-year and 10 years postloading. Multivariable logistic and linear regression models by means of a generalized estimated equation (GEE) were used to evaluate the influence of buccal KM on peri-implant clinical parameters; BOP, MBL, PD, and adjusted for implant type (one-piece or two-piece) and compliance. RESULTS: A total of 35 (24.8%) implants were healthy, 67 (47.5%) had mucositis and 39 (27.6%) were affected by peri-implantitis. In absence of buccal KM (KM = 0 mm), 75% of the implants exhibited mucositis, while in the presence of KM (KMW >0 mm) 41.2% exhibited mucositis. Regarding peri-implantitis, the corresponding percentages were 20% (KM = 0 mm) and 26.7% (KM >0 mm). Unadjusted logistic regression showed that the presence of buccal KM tended to reduce the odds of showing BOP at buccal sites (OR: 0.28 [95% CI, 0.07 to 1.09], p = 0.06). The adjusted logistic regression model revealed that having buccal KM (OR: 0.21 [95% CI, 0.05 to 0.85], p = 0.02) and using two-piece implants (OR: 0.34 [95% CI, 0.15 to 0.75], p = 0.008) significantly reduced the odds of showing BOP. Adjusted linear regression by means of GEE showed that KM and two-piece implants were associated with reduced MBL and MBL changes (p < 0.05). CONCLUSION: The lack of buccal KM appears to be linked with peri-implant parameters such as BOP and MBL, but the association is weak. The design of one-piece implants may account for their increased odds of exhibiting BOP.

Flapless early implant placement into the uncalcified provisional matrix-Does it lead to osseointegration of the implant? A preclinical study.

AIM: To test whether early implant placement into the extraction socket containing an uncalcified provisional matrix leads to successful osseointegration and stable marginal bone levels. MATERIALS AND METHODS: In six mongrel dogs, the mandibular molars were extracted. Three weeks later, early implant placement was performed according to three experimental protocols: (i) flapless implant placement with preservation of the provisional matrix; (ii) flap elevation, socket debridement and implant placement; and (iii) flap elevation, socket debridement, implant placement and guided bone regeneration (GBR). One untreated extraction socket served as a control group. Data analyses were based on histologic slides 3 months after implant placement. RESULTS: There were no differences in bone-to-implant contact between the three experimental groups (66.97%, 58.89% and 60.89%, respectively) (inter-group comparison p = .42). Marginal bone levels, first bone-to-implant contact as well as the thickness of the connective tissue did not reveal any significant differences between the groups (p = .85, .60 and .65, respectively). CONCLUSIONS: Flapless early implant placement into posterior extraction sockets was as effective as an open flap approach in conjunction with GBR. Mineralization of the socket seems to occur irrespective of the presence of dental implants or biomaterials.

Randomized controlled multi-centre study comparing shorter dental implants (6 mm) to longer dental implants (11-15 mm) in combination with sinus floor elevation procedures: 10-year data.

AIM: To compare implant survival and complication rates between shorter and standard-length implants with sinus augmentation and restored with single crowns, at 10 years of loading. MATERIALS AND METHODS: One-hundred and one patients (137 implants) with a ridge height of 5-7 mm in the posterior maxilla were randomly assigned to two treatment modalities: shorter implants (6 mm) (group short [GS]) or standard-length implants (11-15 mm) with sinus grafting (group graft [GG]). Following the insertion of final restorations, patients were regularly recalled for up to 10 years. Assessed outcomes encompassed implant survival, marginal bone levels (MBLs), biological and technical parameters and patient-reported outcome measures (OHIP-49 = Oral Health Impact Profile). Non-parametric statistical analysis was used to analyse the data. RESULTS: For the 5- to 10-year follow-up period, 77 patients with 105 implants (GS: 36 patients/48 implants; GG: 41/57) were available for re-examination (drop-out rate 21%). Implant survival rates at the patient level were 96.0% (GS; 2 failures) and 100% (GG) (inter-group p = .24). Median MBLs amounted to 0.00 mm (min 0.00; max 3.25; GS) and 0.00 mm (min 0.00; max 4.55; GG) (inter-group p = .73). Technical complications predominantly occurred within the first 5 years (inter-group p > .05). Peri-implantitis rates were 4.2% (GS) and 13.3% (GG) (intergroup p = .37). Median OHIP-49 scores were 7.00 (0.00; 39.00; GS) and 9.00 (0.00; 196; GG) (inter-group p = .61) at 10 years. CONCLUSIONS: Based on similar 10-year implant survival rates, reduced patient morbidity and lower costs, the use of shorter dental implants might well serve as an alternative treatment concept to longer implants placed in conjunction with sinus grafting for patients with a limited ridge height in the posterior maxilla. Study register: https://clinicaltrials.gov/ct2/show/NCT01030523.

Augmentation of keratinized tissue using autogenous soft-tissue grafts and collagen-based soft-tissue substitutes at teeth and dental implants: Histological findings in a pilot pre-clinical study.

AIM: To histomorphometrically assess three treatment modalities for gaining keratinized tissue (KT) at teeth and at dental implants. MATERIALS AND METHODS: In five dogs, the distal roots of the mandibular second, third and fourth premolars were extracted. Dental implants were placed at the distal root areas 2 months later. After another 2 months, KT augmentation was performed at both distal (implants) and at mesial root (teeth) areas in the presence (wKT groups) or absence (w/oKT groups) of a KT band at the mucosal/gingival level. Three treatment modalities were applied randomly: apically positioned flap only (APF), free gingival grafts (FGGs) and xenogeneic collagen matrices (XCMs). A combination of the above produced six groups. Two months later, tissue sections were harvested and analysed histomorphometrically. RESULTS: The median KT height and length were greatest at implants with FGG in both wKT (3.7 and 5.1 mm, respectively) and w/oKT groups (3.7 and 4.6 mm), and at teeth with FGG in wKT groups (3.7 and 6.1 mm) and with APF in the w/oKT groups (3.9 and 4.4 mm). The XCM and APF produced more favourable results at teeth than at implants. CONCLUSIONS: FGG was advantageous in gaining KT, especially at implants.

The Apical Tooth Replantation with Surgical Intrusion Technique (ATR-SIT) for Regenerative Treatment of Hopeless Teeth: A Report of Two Cases.

The aim of the present clinical report is to introduce a novel surgical procedure, the "Apical Tooth Replantation with Surgical Intrusion Technique" (ATR-SIT) for managing teeth with hopeless prognosis compromised with a severe endodontal-periodontal lesion, pathologic tooth migration, and gingival recession. Two cases are presented managing teeth diagnosed with a hopeless prognosis. ATR-SIT involves tooth extraction, extra-oral root debridement, root surface conditioning, apicectomy, retrograde filling and the application of enamel matrix derivatives prior to reimplantation. Following reimplantation, the teeth are covered with a combination of autogenous bone chips and bone substitute materials, covered with resorbable membranes. Following ATR-SIT, the patients received either orthodontic treatment or tooth-supported fixed dental prostheses. The described ATR-SIT effectively improved the initially hopeless prognosis of the teeth and maintained periodontal health over time, evidenced by favourable clinical and radiographic outcomes. ATR-SIT might be a potential alternative to tooth extraction of hopeless teeth in patients with stage IV periodontitis.

Clinical Outcomes of Tooth- and Implant-Supported Restorations Performed in a University-based Undergraduate Program after 13-15 Years.

AIMS: To assess the clinical concept of patient treatment with fixed tooth- and implant-supported restorations in a university-based undergraduate program after 13 - 15 years. METHODS: Thirty patients (mean age 56 years) who had received multiple tooth- and implant-supported restorations were recalled after 13-15 years. The clinical assessment comprised of biological and technical parameters as well as patient satisfaction. Data were analyzed descriptively and the 13-15-year survival rates for tooth- and implant-supported single crowns and fixed dental prostheses were calculated. RESULTS: The survival rate of tooth-supported restorations amounted to 88.3% (single crowns) and 69.6% (fixed dental prostheses); in implants it reached 100% for all types of reconstructions. Overall, 92.4% of all reconstructions were free of technical complications. The most common technical complication was chipping of the veneering ceramic (tooth-supported restorations: 5.5%; implant-supported restorations: 13-15.9%) regardless of the material used. At teeth, increased probing depth ≥5mm was the most frequent biological complication (22.8%), followed by endodontic complications of root-canal treated teeth (14%) and loss of vitality at abutment teeth (8.2%). Peri-implantitis was diagnosed in 10.2% of implants. CONCLUSION: Results of this study indicate that the clinical concept implemented in the undergraduate program and performed by undergraduate students works well. The clinical outcomes are similar to those reported in the literature. In general, the majority of biological complications occurrs in reconstructed teeth, whereas implant-supported restorations are more prone to technical complications.

Clinical and histological wound healing patterns of collagen-based substitutes: An experimental randomized controlled trial in standardized palatal defects in humans.

AIM: To evaluate the progression of wound healing of standardized palatal defects in groups using three different collagen-based wound dressings and a control group, in terms of wound closure, pain perception and descriptive histology. MATERIALS AND METHODS: Twenty participants were enrolled in this experimental study, in whom four palatal defects were created. The defects (6 mm diameter, 3 mm depth) were randomly assigned to one of four treatment modalities: C (control), MG (Mucograft®), MD (mucoderm®) and FG (Fibro-Gide®). Photographs were taken, and pain assessment was performed before and after treatment and at 5, 7, 9, 12, 14 and 16 days after surgery. All participants wore a palatal splint for a duration of 16 days. RESULTS: All groups achieved complete wound closure at 14 days. The percentage of the remaining open wound on day 7 amounted to 49.3% (C; interquartile range [IQR]: 22.6), 70.1% (FG; IQR: 20.7), 56.8% (MD; IQR: 26.3) and 62.2% (MG; IQR: 34.4). Statistically significant differences were found between FG and C (p =.01) and between MD and FG (p =.04). None of the participants rated pain higher than 4 out of 10 during the entire study period. CONCLUSIONS: Collagen-based wound dressings provide coverage of open defects, albeit without acceleration of wound closure or reduction of pain. FG (which is not intended for open oral wounds) showed slower wound closure compared to C and MD.

Is transmucosal healing of an implant as effective as submerged healing when simultaneous guided bone regeneration is performed? A preclinical study.

AIM: To investigate whether transmucosal healing is as effective as submerged healing in terms of buccal bone regeneration when guided bone regeneration (GBR) is performed simultaneously with implant placement. MATERIALS AND METHODS: In six dogs, buccal dehiscence defects were created in the edentulous mandibular ridge, sized 5 × 5 × 3 mm (length × height × depth). In each defect, a bone-level implant was placed, and four experimental groups were randomly assigned as follows: (i) transmucosal healing with GBR (T-GBR), (ii) transmucosal healing without GBR (T-control), (iii) submerged healing with GBR (S-GBR) and (iv) submerged healing without GBR (S-control). Data analyses were based on histological slides 5 months after implant placement. RESULTS: The T-GBR group showed significant differences compared to the control groups regarding defect height resolution, buccal bone thickness and mineralized tissue area (p < .05), but showed no significant differences when compared with the S-GBR group (p > .05). CONCLUSIONS: The mode of healing (transmucosal vs. submerged) does not influence bone regeneration at implant sites. The clinician may therefore choose the approach based on further clinical and patient-specific parameters.

Ridge preservation using a self-retaining block type bone substitute for extraction sockets with buccal dehiscence defects - A preclinical study.

OBJECTIVE: To evaluate the effect of a self-retaining block-type bone substitute (srBB) on the dimensional stability of the horizontal ridge width at the coronal level in a buccal dehiscence model. MATERIALS AND METHODS: Four box-shaped bone defects with a buccal dehiscence were surgically prepared in the partially edentulous mandible (n = 6). Experimental biomaterials were randomly assigned to each site: (1) Control group: no treatment, (2) particle-type bone substitute (PBS) group, (3) collagenated soft block bone substitute (csBB) group, and (4) self-retaining synthetic block bone (srBB) group. In all grafted groups, a collagen membrane covered the biomaterials. At 16 weeks, clinical, histological, and radiographic analyses were performed. RESULTS: Three of the six blocks in the srBB group became exposed and fell out during the first week after surgery. Therefore, the remaining three specimens were renamed RsrBB group. The RsrBB group showed an increase horizontal ridge compared to the pristine bone width at 2-4 mm below the CEJ, while the other groups showed resorption (augmented width at 2 mm below: 4.2, 42.4, 36.2, and 110.1% in the control, PBS, csBB, and RsrBB groups, respectively). The mineralized bone area was largest in the RsrBB group (4.74, 3.44, 5.67, and 7.77 mm2 in the control, PBS, csBB, and RsrBB groups, respectively.). CONCLUSIONS: The srBB group demonstrated the highest volume stability at the coronal level. These findings would potentially suggest that self-retaining block bone substitute might be a good candidate for alveolar ridge preservation.

Survival and complication rates of two dental implant systems supporting fixed restorations: 10-year data of a randomized controlled clinical study.

OBJECTIVES: To compare clinical, radiographic, biological and technical long-term outcomes of two types of dental implants over a period of 10 years. MATERIALS AND METHODS: Ninety-eight implants were placed in 64 patients, randomly allocated to one of two manufacturers (AST and STM). All implants were loaded with fixed restorations. Outcome measures were assessed at implant insertion (Ti), at baseline examination (TL), at 1, 3, 5, 8 and 10 (T10) years. Data analysis included survival, bone level changes, complications and clinical measures. RESULTS: Re-examination was performed in 43 patients (23 AST and 20 STM) at 10 years. The implant level analysis was based on 37 (AST) and 32 (STM) implants. Survival rates of 100% were obtained for both groups. The median changes of the marginal bone levels between baseline and T10 (the primary endpoint) amounted to a loss of 0.07 mm for group AST and a gain of 0.37 mm for group STM (intergroup p = 0.008). Technical complications occurred in 27.0% of the implants in group AST and in 15.6% in group STM. The prevalence of peri-implant mucositis was 29.7% (AST) and 50.1% (STM). The prevalence of peri-implantitis amounted to 0% (AST) and 6.3% (STM). CONCLUSIONS: Irrespective of the implant system used, the survival rates after 10 years were high. Minimal bone level changes were observed, statistically significant but clinically negligible in favor of STM. Technical complications were more frequently encountered in group AST, while group STM had a higher prevalence of peri-implant mucositis.

The 'One Customized Abutment One Time' concept - An innovative technique for optimizing immediacy and digital protocols.

Disconnection and reconnection of abutments multiple times have known to affect the mucosal barrier around implants leading to marginal bone loss. This clinical report describes a novel technique that amalgamates the benefits of digital technologies encompassing the fabrication of surgical guides for implant placement, customized hybrid zirconia abutments and all ceramic lithium disilicate crowns prior to implant placement. A correct 3-dimensional implant positioning along with immediate placement of the definitive hybrid customized abutment and a lithium disilicate crown has the potential to reduce treatment time, visits and costs while delivering optimal esthetic outcomes.

Group 5 ITI Consensus Report: Implant placement and loading protocols.

OBJECTIVES: Working Group 5 was convened to discuss and find consensus on the topics of implant placement and loading protocols associated with single missing teeth in the anterior maxilla (aesthetic zone). Consensus statements, clinical recommendations, patient perspectives and future research suggestions were developed and presented to the plenary for discussion and approval. MATERIALS AND METHODS: Two systematic reviews were developed and submitted prior to the conference. The group considered in detail the systematic reviews and developed statements, clinical recommendations, patient perspectives and future research suggestions based on the findings of the reviews and experience of group members. Definitive versions were developed after presentation to and discussion by the plenary. RESULTS: Five consensus statements were developed and approved from each systematic review. Twelve clinical recommendations were developed by the group based on both reviews and experience. Three patient perspectives were developed, and five suggestions made for future research. CONCLUSIONS: Based on the findings of the systematic reviews and experience of group members, the Type 1A protocol (immediate placement and immediate loading), when utilized in the anterior maxilla under favorable conditions, is considered predictable and is associated with high survival rates. The procedure is considered clinically viable and is associated with aesthetic outcomes, although surgical, technical, and biological complications can occur.

Stromal cells associated with soft tissue augmentation by a volume stable collagen matrix (VCMX) are predominated by anti-inflammatory/reparative macrophages.

Aim: To define immunophenotypes of stromal inflammatory and endothelial cells and fibroblasts 3-months post-augmentation of the peri-implant soft tissue using a porcine cross-linked collagen matrix (VCMX). Methods: Peri-implant soft tissue samples were obtained from 12 patients at the lining mucosa (LM) - masticatory mucosa (MM) junction, before and at 3-months post-augmentation. Immunohistochemical stains for identification of inflammatory cells [T (CD3) and B (CD20) lymphocytes, plasma cells (CD138)], macrophages (CD68-pro-inflammatory, CD163-anti-inflammatory/reparative), endothelial cells (CD31, CD34) and fibroblasts (CD90, TE-7), were performed. Differences in the mean positively-stained cells pre- and post-augmentation was analyzed by Wilcoxon Signed-Rank Test. Results: CD31+ endothelial cells showed increased mean numbers in MM2 compared to MM1 (p=0.025) and in LM2 compared to LM1 (p=0.047). CD163+ anti-inflammatory macrophages showed mean numbers in MM2 higher than MM1 (p=0.021) and in LM2 than LM1 (p=0.012). All other cell phenotypes showed insignificant changes between pre- and post-augmentation. Conclusion: This molecular study provided novel insight on the frequency of phenotypes of stromal cells in the wound healing process 3-months post-augmentation with VCMX, with anti-inflammatory CD163+ macrophages being predominant. This should be further investigated in order to find novel therapeutic approaches to modulate and promote the VCMX-related healing process.

Early implant placement in sites with ridge preservation or spontaneous healing: histologic, profilometric, and CBCT analyses of an exploratory RCT.

PURPOSE: The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion. METHODS: Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis. Patients were followed up after the final crown insertion and again at 1 year post-procedure. RESULTS: Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by -2.11 mm for the DBBM-C/CM group, -1.62 mm for the DBBM-C group, and -1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by -0.27 mm for the DBBM-C/CM group, -2.73 mm for the DBBM-C group, and -1.48mm for the SH group. The median contour changes between crown insertion and 1 year were -0.19 mm in the DBBM-C/CM group, -0.09 mm in the DBBM-C group, and -0.29 mm in the SH group. CONCLUSIONS: Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year.

Efficacy of a collagen matrix for soft tissue augmentation after implant placement compared to connective tissue grafts: A multicenter, noninferiority, randomized controlled trial.

OBJECTIVES: To test whether soft tissue volume augmentation using a collagen matrix (VCMX) leads to noninferior results in terms of gain of mucosal thickness at single implant sites, compared to connective tissue grafts (SCTG). METHODS: The study was designed as a multi-center randomized controlled clinical trial. Subjects in need of soft tissue volume augmentation at single tooth implant sites were consecutively recruited at nine centers. The deficient mucosal thickness at the implant sites (one per patient) was augmented by applying either a VCMX or a SCTG. Patients were examined at 120 days (abutment connection = primary endpoint), 180 days (final restoration), and 360 days (1-year after insertion of the final restoration). Outcome measures included: transmucosal probing of the mucosal thickness (crestal = primary outcome), profilometric measurements of the tissue volume, and patient-reported outcome measures (PROMs). RESULTS: Out of the 88 patients, 79 attended the one-year follow-up. The median increase of the crestal mucosal thickness between pre-augmentation and 120 days was 0.3 ± 2.1 mm in the VCMX group and 0.8 ± 1.6 mm in the SCTG group (p = .455). Non-inferiority of the VCMX compared to the SCTG was not observed. The respective numbers at the buccal aspect amounted to 0.9 ± 2.0 mm (VCMX) and 1.1 ± 1.4 mm (SCTG; p = .431). PROMs including pain perception favored the VCMX group. CONCLUSION: It remains inconclusive whether soft tissue augmentation using a VCMX is noninferior to SCTG in terms of crestal mucosal thickening at single implant sites. However, the use of collagen matrices favors PROMs especially pain perception, while achieving similar buccal volume gains along with comparable clinical and aesthetic parameters to SCTG.