It is all about peri-implant tissue health

Does platelet-rich fibrin enhance the outcomes of peri-implant soft tissues? A systematic review

BACKGROUND

Improving soft tissue quality and quantity around dental implants is crucial for successful outcomes. Platelet-Rich Fibrin (PRF) is showing promise in enhancing wound healing and implant stability. This systematic review aims to evaluate the clinical benefits of PRF in soft tissue regeneration around dental implants compared to standard methods.

METHODS

This systematic review adhered to the PRISMA guidelines and utilizing the PICO methodology, investigated the use of Platelet-Rich Fibrin (PRF) in soft tissue augmentation during implant therapy. The primary outcomes assessed include the width of keratinized mucosa and soft tissue thickness, comparing PRF interventions to standard techniques.The study included randomized controlled trials (RCTs) and comparative studies, focusing on human patients needing implant therapy with or without PRF. An extensive search of databases and manual references was conducted; data extraction involved assessing study quality and risk of bias, but due to high heterogeneity among studies, a meta-analysis was not feasible, leading to a systematic review of the available literature.

RESULTS

A total of 766 references were initially identified, with 29 being eligible after screening. Nine studies were included for detailed review. The findings revealed that PRF is effective in increasing the width of keratinized mucosa (KT) and soft tissue thickness (STT) around implants. Even if free gingival grafts (FGG) sometimes performed better. However, the differences between PRF and FGG were not clinically significant, and PRF offers lower cost, ease of use, and reduced morbidity. There was limited information on the esthetic outcomes of PRF, with only two studies addressing this aspect, showing mixed results.

CONCLUSION

Overall, PRF demonstrated positive effects on KT width and STT, but further research with rigorous methodology and larger sample sizes is needed to better understand its impact on implants health and esthetics.

Enhanced functionality and migration of human gingival fibroblasts on vacuum ultraviolet light-treated titanium: An implication for mitigating cellular stress to improve peri-implant cellular reaction

PURPOSE

The maintenance of peri-implant health relies significantly on the integrity of the peri-implant seal, particularly vulnerable at the interface between implant abutment and soft tissue. Early healing stages around implants involve cellular exposure to oxidative stress. This study aimed to investigate whether vacuum ultraviolet (VUV)-treated titanium augments the growth and functionality of human gingival fibroblasts while mitigating cellular stress.

METHODS

Machined titanium plates underwent treatment with 172 nm VUV light for one minute, with untreated plates as controls. Human gingival fibroblasts were cultured on treated and untreated plates, and their behavior, growth, and functionality were assessed. Functionally impaired fibroblasts, treated with hydrogen peroxide, were also cultured on these titanium plates, and plate-to-plate transmigration ability was evaluated.

RESULTS

Fibroblasts on VUV-treated titanium exhibited a 50% reduction in intracellular reactive oxygen species production compared to controls. Additionally, glutathione, an antioxidant, remained undepleted in cells on VUV-treated titanium. Furthermore, the expression levels of inflammatory cytokines IL-1β and IL-8 decreased by 40-60% on VUV-treated titanium. Consequently, fibroblast attachment and proliferation doubled on VUV-treated titanium compared to those in the controls, leading to enhanced cell retention. Plate-to-plate transmigration assays demonstrated that fibroblasts migrated twice as far on VUV-treated surfaces compared to those in the controls. In particular, the transmigration ability, impaired in functionally impaired fibroblasts on the controls, was preserved on VUV-treated titanium.

CONCLUSIONS

VUV-treated titanium promotes the growth, function, and migration of human gingival fibroblasts by reducing cellular stress and enhancing antioxidative capacity. Notably, the transmigration ability significantly improved on VUV-treated titanium.

Antibacterial and Osteogenesis Promotion of Bionic Extracellular Matrix Implant Coating Based on Gallic Acid Self-Assembly

Oral health problems, particularly tooth defects, can significantly affect people's quality of life and overall well-being. The development of titanium (Ti) dental implants has largely replaced natural tooth roots to prevent periodontal and gastrointestinal diseases. However, challenges such as postoperative bacterial infections and poor osseointegration continue to hinder progress in dental implant technology. To tackle these issues, we used hydroxypropyl trimethylammonium chloride chitosan (HACC) and gallic acid-modified gelatin (GAG) to create extracellular matrix (ECM) coatings on titanium using layer-by-layer self-assembly. GAG showed better water solubility at room temperature, being over 99.0 times more soluble than regular gelatin. In vivo and in vitro analyses of the ECM coatings revealed their antibacterial properties and their ability to promote osteogenic differentiation, resulting in over 31.5 times more calcareous deposits than Ti. This strategy shows potential for improving oral health and reducing the complications associated with dental implants in clinical settings.

A digital way to assess the stain parameters that lead to soft tissue blanching when delivering an implant-supported crown

BACKGROUND

Dental implant systems provide standard cylindrical healing abutments of various diameters; however, they do not match the larger shape of the complex emergence profile of the prosthetic crowns. Adaptation of the soft tissues from a circular emergence profile to the one that suits the prosthetic crown involves a simultaneous squeezing and stretching of the gingiva. Often, this translates into local blanching of the gingiva and the prosthodontist must assess that blanching is transient. There is no literature about how much strain exerted by the prosthetic crown is leading or not to gingiva blanching. Aim of this paper is to present a digital workflow that allows measuring, upon prosthesis delivery, how much the strained gingiva is displaced under the crown and leads or not to blanching of the peri-implant soft tissues.

METHOD AND RESULTS

The digital workflow involves 3 intra-oral scans (IOS), IOS#1 at completion of the soft tissue healing, IOS#2 at prosthesis delivery, IOS#3 after soft tissue conditioning, and the STL files of the healing cap, the abutment, the implant and the prosthetic crown. The above are superposed and merged following a dedicated protocol that provides access to the distance the delivered crown deforms the strained gingiva. The present case study displayed distinct blanching intensities. Severe blanching was present when the strains applied to the gingiva caused a displacement of 1.3 mm and above; a displacement of 0.9 mm led to moderate blanching. No blanching was observed up to a displacement of 0.6 mm.

CONCLUSION

A digital protocol, involving the superposition and merging of IOSs taken along a defined timeline and STLs of the implant hardware, allowed measuring the displacement distances a prosthetic crown wields upon delivery on the gingiva beneath the prosthesis. Various intensities of gingiva blanching could be related to distinct displacement distances of the healed gingiva that were triggered by attaching a prosthetic crown to the implant neck.

Efficacy and safety of erythritol air-polishing in implant dentistry: A systematic review

OBJECTIVES

Professional oral hygiene is essential to prevent peri-implant disease. Appropriate instruments should be employed for implant-supported restorations: they should effectively remove deposits without damaging dental implant surface. The aim of the present systematic review is to investigate the efficacy and safety of erythritol air-polishing in implant-supported rehabilitations, compared to alternative hygienic techniques.

MATERIALS AND METHODS

The guidelines reported in the indications of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) were employed for this systematic review. The focused question was: 'what is the effect of erythritol air-polishing on dental implant surfaces regarding its cleansing efficacy and/or safety?' The final online search was conducted on 13 August 2023; MEDLINE-PubMed, Scopus and Cochrane Library were employed. Comparative in vitro or in vivo original studies were included.

RESULTS

The initial database search yielded 128 entries; the final selection comprised 15 articles. The risk of bias was evaluated using the Newcastle Ottawa scale (NOS), the Cochrane Handbook for Systematic Reviews of Interventions, GRADE method. Ultrasonic scaling with PEEK tips, glycine air-polishing and cold atmospheric plasma were the devices most frequently compared to erythritol powder in the included studies. Erythritol air-polishing appeared to be significantly more effective in reducing biofilm compared to other treatments, without causing any significant damage to the implant surface and peri-implant tissues, promoting a good biological response.

CONCLUSION

Erythritol air-polishing showed promising results for professional oral hygiene in implant-supported restorations. According to this systematic review, it is effective and safe for removing biofilm from titanium dental implants.

Revolutionizing oral care: Reactive oxygen species (ROS)-Regulating biomaterials for combating infection and inflammation

The human oral cavity is home to a delicate symbiosis between its indigenous microbiota and the host, the balance of which is easily perturbed by local or systemic factors, leading to a spectrum of oral diseases such as dental caries, periodontitis, and pulp infections. Reactive oxygen species (ROS) play crucial roles in the host's innate immune defenses. However, in chronic inflammatory oral conditions, dysregulated immune responses can result in excessive ROS production, which in turn exacerbates inflammation and causes tissue damage. Conversely, the potent antimicrobial properties of ROS have inspired the development of various anti-infective therapies. Therefore, the strategic modulation of ROS by innovative biomaterials is emerging as a promising therapeutic approach for oral infection and inflammation. This review begins by highlighting the state-of-the-art of ROS-regulating biomaterials, which are designed to generate, scavenge, or modulate ROS in a bidirectional manner. We then delve into the latest innovations in these biomaterials and their applications in treating a range of oral diseases, including dental caries, endodontic and periapical conditions, periodontitis, peri-implantitis, and oral candidiasis. The review concludes with an overview of the current challenges and future potential of these biomaterials in clinical settings. This review provides novel insights for the ongoing development of ROS-based therapeutic strategies for oral diseases.

Potential Impact of Microbial Variations After Peri-Implantitis Treatment on Peri-Implant Clinical, Radiographic, and Crevicular Parameters: A Systematic Review

Objectives: This systematic review evaluated concomitant trends in microbial (total biofilm load and pre-dominant pathogens' counts) and clinical, radiographic, and crevicular variations following (any) peri-implantitis treatment in partially vs. totally edentulous, systemically healthy, non-smoking adults and compared them to peri-implant mucositis treated sites. Methods: The study protocol, compliant with the PRISMA statement, was registered on PROSPERO (CRD42024514521). Findings from six randomized controlled trials (RCTs), evaluated through the ROBINS-2 tool, were qualitatively synthesized. Results: No data concerning total edentulism and treated peri-implant mucositis sites were retrieved from the included RCTs. Instead, as expected, in the partially edentulous subjects, peri-implantitis treatments effectively provided biofilm control, although Plaque Index (PI) tended to increase again over time. Notably, Bleeding on Probing (BoP) rose slightly after treatment but decreased markedly by three months, indicating, at least, a partial resolution of the infective-inflammatory process. Probing Depth (PD) showed a slower but consistent improvement throughout. Despite a return of PI levels by twelve months, BoP and PD continued to improve, underscoring the successful long-term outcomes of peri-implantitis treatment. Over time, variations in PI did not consistently reflect changes in predominant pathogenic species, especially at the 1-month follow-up; BoP aligned with predominant pathogens rather than total microbial biofilm load at the 1- and 3-month follow-ups, and PD did the same at the 3- and 6-month follow-ups, likely affecting peri-implantitis-associated microbiota. No data concerning crevicular parameters were retrieved in the included RCTs, and the extracted radiographic outcomes were not comparable. Conclusions: The impact of the microbial variations after peri-implantitis treatment on peri-implant clinical parameters highlight the critical role of dysbiosis, rather than total microbial load, in influencing inflammation and tissue destruction, emphasizing the need for targeted approaches to manage persistent pathogens and improve treatment efficacy.

Systematic review of peri-implant conditions and aesthetic outcomes of customized versus conventional healing abutments

PURPOSE

Customized healing abutments are utilized to enhance aesthetics and peri-implant soft and hard tissue health, and play a crucial role in the implant-prosthetic workflow. This systematic review was performed to assess and compare the clinical outcomes of customized healing abutments with conventional ones.

METHODS

The review was registered with PROSPERO (ID: CRD42024532449) and followed the PRISMA-guidelines. The PICO-question addressed was: "In patients with dental implants, do customized healing abutments result in beneficial peri-implant conditions compared with conventional healing abutments?" Clinical trials involving immediate and late implant placement that compared different healing abutments based on quantifiable outcomes were included. The "PubMed", "PubMed Central", "Cochrane Library", and "Web of Science databases" were screened for eligible studies until 4/20/2024.

RESULTS

Of 1,396 titles retrieved, 5 studies met the inclusion criteria and were analyzed. The included studies showed a low risk of bias as assessed by the RoB2 tool and Joanna Briggs Institute Critical Assessment questionnaire. Compared to conventional healing abutments, customized abutments were associated with a trend toward better clinical outcomes in peri-implant soft and hard tissue, as well as aesthetics. Several results within the cohorts using customized healing abutments showed significantly improved values in soft and hard tissue results as well as aesthetic parameters. Importantly, none of the included studies reported biological or aesthetic disadvantages associated with the use of customized healing abutments.

CONCLUSIONS

Customized healing abutments maintain stability of peri-implant hard and soft tissue. However, further studies with larger sample sizes and longer follow-up periods are needed to validate these findings.

Current status and management of peri-implantitis: A systematic review

AIM

To systematically review the literature on the surgical and non-surgical methods for managing peri-implantitis.

MATERIALS AND METHODS

An electronic search for randomised controlled trials published between 2019 and 2023 in the English language was performed with the Medline/PubMed database according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The specific search terms were "periimplantitis", "non-surgical treatment", "surgical treatment" and combinations of these terms.

RESULTS

The initial search yielded 2,704 relevant articles. Most of these articles were excluded based on publication type and year. At this stage, only two articles were excluded from the study because they were not written in English. Of the remaining 98 articles, seven were eliminated because the full text could not be accessed, and the others were excluded because their study topics and types were not within the scope of this review. Six out of the 51 studies, whose full texts were assessed for eligibility, were further excluded. Finally, 45 articles that met the inclusion criteria of this review were evaluated.

CONCLUSION

Personalised and evidence-based approaches in the treatment of peri-implantitis are at the forefront in achieving the long-term success of peri-implantitis therapy. Further evidence is needed for the outcomes of surgical or non-surgical peri-implantitis treatment methods applied alone or with adjunctive therapies.

Preclinical Experimental Study on New Cervical Implant Design to Improve Peri-Implant Tissue Healing

Objectives: In this preclinical study, we used an experimental rabbit model to investigate the effects of a new implant design that involves specific changes to the cervical portion, using a conventional implant design in the control group. Materials and Methods: We used 10 rabbits and 40 dental implants with two different macrogeometries. Two groups were formed (n = 20 per group): the Collo group, wherein implants with the new cervical design were used, which present a concavity (reduction in diameter) in the first 3.5 mm, the portion without surface treatment; the Control group, wherein conical implants with the conventional design were used, with surface treatment throughout the body. All implants were 4 mm in diameter and 10 mm in length. The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T1) and sample removal (T2 and T3). The animals (n = five animals/time) were euthanized at 3 weeks (T1) and 4 weeks (T2). Histological sections were prepared and the bone-implant contact (BIC%) and tissue area fraction occupancy (TAFO%) percentages were analyzed in the predetermined cervical area; namely, the first 4 mm from the implant platform. Results: The ISQ values showed no statistical differences at T1 and T2 (p = 0.9458 and p = 0.1103, respectively) between the groups. However, at T3, higher values were found for the Collo group (p = 0.0475) than those found for the Control group. The Collo samples presented higher BIC% values than those of the Control group, with statistical differences of p = 0.0009 at 3 weeks and p = 0.0007 at 4 weeks. There were statistical differences in the TAFO% (new bone, medullary spaces, and the collagen matrix) between the groups at each evaluation time (p < 0.001). Conclusions: Considering the limitations of the present preclinical study, the results demonstrate that the new implant design (the Collo group) had higher implant stability (ISQ) values in the samples after 4 weeks of implantation. Furthermore, the histomorphometric BIC% and TAFO% analyses showed that the Collo group had higher values at both measurement times than the Control group did. These findings indicate that changes made to the cervical design of the Collo group implants may benefit the maintenance of peri-implant tissue health.

Effect of ultraviolet treatment on soft tissue healing and bacterial attachment to titania-coated zirconia

Zirconia is the most promising implant abutment material due to its excellent aesthetic effect, good biocompatibility and corrosion resistance. To obtain ideal soft tissue sealing, the implant abutment surface should facilitate cell adhesion and inhibit bacterial colonization. In this study, pre-sintered zirconia was placed in a suspension of titania (TiO2) and zirconium oxychloride (ZrOCl2) and heated in a water bath for dense sintering. A titania coating was prepared on the zirconia surface and subjected to UV irradiation. The surface morphology, elemental composition and chemical state of each group of samples were analyzed by scanning electron microscope, x-ray energy spectrometer, x-ray photoelectron spectroscopy and x-ray diffraction. The responses of human gingival fibroblasts (HGFs) and common oral pathogensStreptococcus mutans(S. mutans) andPorphyromonas gingivalis(P. gingivalis) to modified zirconia were systematically assessed. Our findings demonstrated that the surface of titania-coated zirconia after UV irradiation produced a large number of hydroxyl groups, and its hydrophilicity was significantly improved. Meanwhile, the UV irradiation also greatly removed the hydrocarbon contaminants on the surface of the titania-coated zirconia. The UV-treated titania coating significantly promoted the proliferation, spreading, and up-regulation of adhesion-related genes and proteins of HGFs. Furthermore, the titania coating irradiated with UV could reduce the adhesion, colonization and metabolic activity ofS. mutansandP. gingivalis. Therefore, UV irradiation of titania-coated zirconia can promote the biological behavior of HGFs and exert a significant antibacterial effect, which has broad clinical application prospects for improving soft tissue integration around zirconia abutments.

Necessity of removing implant-supported prostheses when conducting supportive peri-implant therapy: A clinical study

STATEMENT OF PROBLEM

Poor or lack of adherence to supportive peri-implant therapy (SPIT) or supportive care has been associated with a significantly higher rate of peri-implantitis or peri-implant mucositis. However, whether therapy with or without the removal of an implant-supported prosthesis yields different outcomes remains unclear.

PURPOSE

The purpose of this clinical study was to evaluate the efficacy of ultrasonic devices in treating participants with or without the removal of implant-supported prostheses after more than 12 months of loading.

MATERIAL AND METHODS

Twenty participants with 23 implant-supported fixed prostheses (39 implants) with indications for removal were included in this study. The following clinical parameters were recorded before the prostheses were removed: the maximum probing depth (PDmax), bleeding on probing (BOP), months of loading, and complications. Each prosthesis was removed and treated with a regular plaque indicator test and then reinserted. This was followed by the intraoral administration of regular supportive therapy via ultrasonically driven polyetheretherketone instrument tips. After instrumentation, the prostheses were removed to access the area positively stained for calculus or biofilm. PT0 and PT1 show the plaque coverage before and after intraoral ultrasonic cleaning, respectively. The reduction in the positive staining area and the efficacy of ultrasonic cleaning with or without prosthesis removal were measured. The Kolmogorov-Smirnov test was performed to verify that the sample data were normally distributed. Comparisons between PT0 and PT1 were conducted via paired t tests, followed by the Student t test for comparisons between groups (α=.05).

RESULTS

A 27.3 ±15.0% reduction in plaque coverage was observed after the implant restorations had been cleaned intraorally. The efficacy of intraoral ultrasonic cleaning was only 45.4 ±20.6%, with a residual plaque rate of 54.6%. Cleaning without the removal of implant-supported restorations was less effective in participants with a PD >5 mm than in the other participants (P=.001). Neither the emergence angle nor the emergence profile had a significant influence on the cleaning effectiveness (P>.05).

CONCLUSIONS

Biofilms at the abutment-prosthesis connection and mucosal and proximal surfaces of the prosthesis may not be effectively cleaned by conventional SPIT. Biofilm reduction is improved by prosthesis removal when the PD is >5 mm.

Volumetric changes of porcine collagen matrix and free gingival grafts for soft-tissue grafting to increase the width of keratinized tissue around dental implants: a retrospective clinical study

AIM

To compare three-dimensional changes of aporcine derived collagen matrix (CM) and free gingival grafts (FGG) for increasing keratinized tissue (KT) at dental implants over a 24-month follow-up period.

MATERIALS AND METHODS

This retrospective study enrolled 25 patients exhibiting 41 implants with deficient KT width (i.e., < 2 mm) who underwent soft tissue augmentation using either CM (11 patients/15 implants) or FGG (14 patients/26 implants). The primary outcome was tissue thickness change (mm) at treated implant sites between 1- (S0), 12- (S1), and 24-months (S2). Secondary outcome was the changes of KT width over a 24-month follow-up period.

RESULTS

Dimensional analyses from S0 to S1 and from S0 to S2 revealed a mean decrease in tissue thickness of -0.05 ± 0.35 mm and - 0.31 ± 0.41 mm in the CM group, and - 0.23 ± 0.38 mm and - 0.22 ± 0.81 mm in the FGG group, with no significant differences found between the groups (S0-S1: p = 0.14, S0-S2: p = 0.58). Within S1 and S2, the CM and FGG groups displayed comparable tissue thickness reduction (CM: -0.32 ± 0.53 mm, FGG: -0.02 ± 0.21 mm; p = 0.07). The FGG group exhibited a significantly greater KT gain 24-months compared to the CM group (CM: 1.50 ± 1.14 mm, FGG: 4.04 ± 1.65 mm; p < 0.001).

CONCLUSIONS

CM and FGG were associated with comparable three-dimensional thickness changes over a period of 24 months. A significantly wider KT band could be established in the FGG group.

Role of immune dysregulation in peri-implantitis

Peri-implantitis, a complex condition that can lead to dental implant failure, is characterized by inflammatory destruction resulting from immune dysregulation. Oral microbial dysbiosis and foreign body stimulation are the main factors contributing to such dysregulation, impairing immune cell function and triggering an inflammatory response. Immune dysregulation plays a critical role in the pathophysiology of peri-implantitis, impacting the balance of T cell subsets, the production of inflammatory factors, and immune-related molecular signaling pathways. Understanding the relationship between immune dysregulation and peri-implantitis is crucial for developing targeted strategies for clinical diagnosis and individualized treatment planning. This review explores the similarities and differences in the immune microenvironment of oral bacterial infections and foreign body rejection, analyzes the relevant molecular signaling pathways, and identifies new key targets for developing innovative immunotherapeutic drugs and effective and personalized treatment modalities for peri-implantitis. Additionally, it addresses the challenges and potential directions for translating immunotherapy into clinical practice for peri-implantitis, offering insights that bridge the gaps in current literature and pave the way for future research.

Modified Roll Envelope Technique Combined With Apically Repositioned Flap (MRARF) for Peri-Implant Soft Tissue Augmentation-A Case Series

In the present case series, we performed implant surgery using a modified roll envelope technique and an apically repositioned flap (MRARF). To improve patients' peri-implant soft tissue phenotypes, they underwent dental implantation following the buccal contour concavities, inadequate keratinized tissue width, and soft tissue thickness simultaneously. This case series includes 4 patients treated between July 2021 and February 2022 who received dental implants and guided bone regeneration treatment 6 months earlier and were to be taken up for second-stage surgery. They were eligible for the MRARF technique if each implant site showed a labial and buccal deficiency and a reduced keratinized mucosa width than the adjacent teeth. Sutures were removed 2 weeks after surgery, and a provisional restoration was delivered. A final impression was taken at 6 weeks to produce the definitive implant-supported restoration. All surgery sites healed uneventfully, and no postoperative pain or excessive swelling was reported. The modified flap design allowed for increasing the width and thickness of keratinized mucosa with a minimally invasive technique. A harmonious color, texture, and mucogingival junction position that matched the surrounding tissue and adjacent teeth was achieved, and all patients were satisfied with the final results. MRARF at second-stage implant surgery could obtain satisfactory results regarding vertical and horizontal aesthetic gingival contours and an adequate width and thickness of keratinized mucosa around the implants.

Peri-Implantitis-Associated Microbiota before and after Peri-Implantitis Treatment, the Biofilm "Competitive Balancing" Effect: A Systematic Review of Randomized Controlled Trials

This systematic review of RCTs aimed to characterize short- and long-term changes in peri-implantitis-associated microbiota (total biofilm microbial load and predominant pathogens' counts) following (any) peri-implantitis treatment in systemically healthy, non-smoking, partially/totally edentulous adults. The study protocol, compliant with the PRISMA statement, was registered on PROSPERO (CRD42024514521) before the literature search. Data from 11 RCTs, assessed through the ROBINS-2 tool, were qualitatively synthesized. No data were retrieved on total edentulism, healthy peri-implant/periodontal sites, treated mucositis, gingivitis, and periodontitis sites. Shortly after treatment, Prevotella intermedia, Fusobacterium nucleatum, and Peptostreptococcus micros prevailed, indicating early colonization, as after implant placement. After both surgical and non-surgical approaches, although not eradicated, the peri-implant total biofilm load, red- and orange-complex species, and Aggregatibacter actinomycetemcomitans counts generally decreased for up to about three months. However, one month after treatment, red-complex species and Prevotella intermedia increased, likely due to persistent tissue-invasive bacteria, unresolved pathological conditions (high probing depth values) favoring anaerobiosis and dysbiosis, and a qualitatively and quantitatively decreased biofilm community, competing and balancing the predominant pathogens (biofilm "competitive balancing" effect), thus allowing recolonization by more virulent bacteria. Red-complex bacteria gradually leveled off to baseline at the six- and twelve-month follow-ups. Fusobacterium nucleatum remained almost unchanged after treatment.

Mandibular overdentures retained by 1 or 2 implants: a 5-year randomized clinical trial on implant stability and peri-implant outcomes

AIM

This is a report of the 5-year results of a two-group parallel randomized clinical trial comparing longitudinal implant stability, and clinical and radiographic peri-implant outcomes of mandibular overdentures retained by one (1-IOD group) or two (2-IOD group) implants.

METHODS

All participants received 4.1 mm diameter tissue-level implants (Straumann® Standard Plus - SLActive®, Institut Straumann AG), installed in the mandible midline (1-IOD; n = 23) or the lateral incisor-canine area bilaterally (2-IOD; n = 24), and loaded after 3 weeks. Implant Stability Quotient (ISQ) was measured using a resonance frequency device (Osstell® Mentor, Integration Diagnostics) at implant placement, after three weeks (loading), and at the 6-month, 1-, 3-, and 5-year follow-ups. Marginal bone loss and clinical implant outcomes (plaque, calculus, suppuration and bleeding) were assessed periodically up to 5 years after loading.

RESULTS

Only minor changes in marginal bone level were observed after 5 years (mean = 0.37; SD = 0.44 mm), and satisfactory and stable peri-implant parameters were observed throughout the 5-year follow-up. No significant differences between groups were found. Overall, the mean primary implant stability was considered high (> 70) for the two groups (1-IOD = 78.1 ± 4.5; 2-IOD = 78.0 ± 5.8). No noticeable changes were observed between implant insertion and loading. A marked increase was observed from insertion to the 6-month follow-up - the mean difference for the 1-IOD group was + 5.5 ± 5.5 (Effect size = 1.00), while for the 2-IOD group, the mean difference was + 6.0 ± 5.6 (Effect size = 1.08). No relevant changes were observed throughout the follow-up periods up to 5 years. Linear mixed-effect model regression showed no influence of the bone-related variables (p > 0.05) and the number of implants (p = 0.087), and a significant effect of the time variable (p < 0.001).

CONCLUSION

Satisfactory peri-implant outcomes and stable secondary stability suggest good clinical performance and successful long-term osseointegration of the implants for single and two-implant mandibular overdentures. Using a single implant to retain a mandibular overdenture does not seem to result in detrimental implant loading over the five years of overdenture use.

CLINICAL RELEVANCE

This study corroborates the use of a single implant to retain a mandibular denture.

Influence of mucosal tissue height on implant crestal bone: A 10-year follow-up of a controlled clinical trial

OBJECTIVE

To evaluate the 10-year influence of soft tissue height (STH) on crestal bone level changes (CBC) in bone-level implants with non-matching internal conical connections.

MATERIAL & METHODS

From the initial 97 patients, 59 (19 men, 40 women, age 55.86 ± 9.5 years) returned for the recall visit. Based on baseline STH, they were categorized into T1 (thin STH ≤2 mm, n = 33), T2 (thin STH augmented with allogenic tissue matrix (ATM), n = 32), and C (thick STH >2 mm, n = 32). Implants were placed in the posterior mandible using a one-stage approach and received single screw-retained restorations. Clinical (PPD, BOP, PI) and radiographic examinations were conducted after 10 years, with CBC calculated mesial and distal to each implant.

RESULTS

After 10 years, implants in surgically thickened (T2) or naturally thick STH (C) showed bone gains of 0.57 ± 0.55 mm and 0.56 ± 0.40 mm, respectively (p < 0.0001) shifting from an initial CBC of -0.21 ± 0.33 mm to 0.36 ± 0.29 mm in the thick STH group and -0.2 ± 0.35 mm to 0.37 ± 0.29 mm in the surgically thickened STH group. Implants in naturally thin STH yielded a non-significant trend of bone loss (-0.12 ± 0.41 mm; p > 0.05).

CONCLUSIONS

Implants in thin STH (≤2 mm) exhibited greater CBC over the study period. Significant bone gains were observed in thick STH cases, indicating that naturally thick STH or STH augmentation with ATM may contribute to maintain CBC in long-term around implants.

CLINICAL SIGNIFICANCE

This is the first long-term follow-up study suggesting that adequate soft tissue height around implants helps maintain stable peri‑implant bone levels. While tissue thickness plays a key role, other factors also interact with peri‑implant tissue height to sustain crestal bone stability over time.

Silk fibroin microgrooved zirconia surfaces improve connective tissue sealing through mediating glycolysis of fibroblasts

The use of zirconia has significantly enhanced the aesthetic outcomes of implant restorations. However, peri-implantitis remains a challenge to long-term functionality of implants. Unlike the perpendicularly arranged collagen fibers in periodontal tissue, those in peri-implant tissue lie parallel to the abutment surface and contain fewer fibroblasts, making them more prone to inflammation. Studies have shown that microgroove structures on implant abutments could improve surrounding soft tissue structure. However, creating precise microgrooves on zirconia without compromising its mechanical integrity is technically challenging. In this study, we applied inkjet printing, an additive manufacturing technique, to create stable silk fibroin microgroove (SFMG) coatings of various dimensions on zirconia substrates. SFMG significantly improved the hydrophilicity of zirconia and showed good physical and chemical stability. The SFMG with 90 μm interval and 10 μm depth was optimal in promoting the proliferation, alignment, and extracellular matrix production of human gingival fibroblasts (HGFs). Moreover, the in vitro results revealed that SFMG stimulated key glycolytic enzyme gene expression in HGFs via the PI3K-AKT-mTOR pathway. Additionally, the in vivo results of histological staining of peri-abutments soft tissue showed that SFMG promoted the vertical alignment of collagen fibers relative to the abutment surface, improving connective tissue sealing around the zirconia abutment. Our results indicated that SFMG on zirconia can enhance HGF proliferation, migration and collagen synthesis by regulating glycolysis though PI3K-AKT-mTor pathway, thereby improving connective tissue sealing.

Evaluation of peri-implant perfusion in patients who underwent avascular augmentation or microvascular reconstruction using laser Doppler flowmetry and tissue spectrophotometry: a prospective comparative clinical study

OBJECTIVES

The aim of this study was to evaluate the peri-implant perfusion, such as oxygen saturation, the relative amount of hemoglobin, and blood flow, in implants placed in pristine bone and avascular and microvascular grafts using a non-invasive measurement method.

MATERIALS AND METHODS

A total of 58 patients with 241 implants were included. Among them, 106 implants were based in native bone (group I), 75 implants were inserted into avascular bone grafts (group II), and 60 implants were placed in microvascular bone grafts (group III). Gingival perfusion was measured using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS). Implants with signs of gingival inflammation were excluded to analyze healthy implant perfusion in different bony envelopes.

RESULTS

The mean values for oxygen saturation, relative hemoglobin levels, and blood flow did not differ significantly between the groups (p = 0.404, p = 0.081, and p = 0.291, respectively). There was no significant difference in perfusion between implants that were surrounded by mucosa and implants based within cutaneous transplants (p = 0.456; p = 0.628, and p = 0.091, respectively).

CONCLUSION

No differences in perfusion were found between implants inserted into native bone and implants involving bone or soft tissue augmentation. However, implants based in avascular and microvascular transplants showed higher rates of peri-implant inflammation.

CLINICAL RELEVANCE

Peri-implant perfusion seems to be comparable for all implants after they heal, irrespective of their bony surroundings. Although perfusion does not differ significantly, other factors may make implants in avascular and microvascular transplants vulnerable to peri-implant inflammation.

Nano-Based Approaches in Surface Modifications of Dental Implants: A Literature Review

Rehabilitation of fully or partially edentulous patients with dental implants represents one of the most frequently used surgical procedures. The work of Branemark, who observed that a piece of titanium embedded in rabbit bone became firmly attached and difficult to remove, introduced the concept of osseointegration and revolutionized modern dentistry. Since then, an ever-growing need for improved implant materials towards enhanced material-tissue integration has emerged. There is a strong belief that nanoscale materials will produce a superior generation of implants with high efficiency, low cost, and high volume. The aim of this review is to explore the contribution of nanomaterials in implantology. A variety of nanomaterials have been proposed as potential candidates for implant surface customization. They can have inherent antibacterial properties, provide enhanced conditions for osseointegration, or act as reservoirs for biomolecules and drugs. Titania nanotubes alone or in combination with biological agents or drugs are used for enhanced tissue integration in dental implants. Regarding immunomodulation and in order to avoid implant rejection, titania nanotubes, graphene, and biopolymers have successfully been utilized, sometimes loaded with anti-inflammatory agents and extracellular vesicles. Peri-implantitis prevention can be achieved through the inherent antibacterial properties of metal nanoparticles and chitosan or hybrid coatings bearing antibiotic substances. For improved corrosion resistance various materials have been explored. However, even though these modifications have shown promising results, future research is necessary to assess their clinical behavior in humans and proceed to widespread commercialization.

Experimental models for peri-implant diseases: a narrative review

OBJECTIVES

Peri-implant diseases, being the most common implant-related complications, significantly impact the normal functioning and longevity of implants. Experimental models play a crucial role in discovering potential therapeutic approaches and elucidating the mechanisms of disease progression in peri-implant diseases. This narrative review comprehensively examines animal models and common modeling methods employed in peri-implant disease research and innovatively summarizes the in vitro models of peri-implant diseases.

MATERIALS AND METHODS

Articles published between 2015 and 2023 were retrieved from PubMed/Medline, Web of Science, and Embase. All studies focusing on experimental models of peri-implant diseases were included and carefully evaluated.

RESULTS

Various experimental models of peri-implantitis have different applications and advantages. The dog model is currently the most widely utilized animal model in peri-implant disease research, while rodent models have unique advantages in gene knockout and systemic disease induction. In vitro models of peri-implant diseases are also continuously evolving to meet different experimental purposes.

CONCLUSIONS

The utilization of experimental models helps simplify experiments, save time and resources, and promote advances in peri-implant disease research. Animal models have been proven valuable in the early stages of drug development, while technological advancements have brought about more predictive and relevant in vitro models.

CLINICAL RELEVANCE

This review provides clear and comprehensive model selection strategies for researchers in the field of peri-implant diseases, thereby enhancing understanding of disease pathogenesis and providing possibilities for developing new treatment strategies.

Balancing Bioresponsive Biofilm Eradication and Guided Tissue Repair via Pro-Efferocytosis and Bidirectional Pyroptosis Regulation during Implant Surgery

There is an increasingly growing demand to balance tissue repair guidance and opportunistic infection (OI) inhibition in clinical implant surgery. Herein, we developed a nanoadjuvant for all-stage tissue repair guidance and biofilm-responsive OI eradication via in situ incorporating Cobaltiprotoporphyrin (CoPP) into Prussian blue (PB) to prepare PB-CoPP nanozymes (PCZs). Released CoPP possesses a pro-efferocytosis effect for eliminating apoptotic and progressing necrotic cells in tissue trauma, thus preventing secondary inflammation. Once OIs occur, PCZs with switchable nanocatalytic capacity can achieve bidirectional pyroptosis regulation. Once reaching the acidic biofilm microenvironment, PCZs possess peroxidase (POD)-like activity that can generate reactive oxygen species (ROS) to eradicate bacterial biofilms, especially when synergized with the photothermal effect. Furthermore, generated ROS can promote macrophage pyroptosis to secrete inflammatory cytokines and antimicrobial proteins for biofilm eradication in vivo. After eradicating the biofilm, PCZs possess catalase (CAT)-like activity in a neutral environment, which can scavenge ROS and inhibit macrophage pyroptosis, thereby improving the inflammatory microenvironment. Briefly, PCZs as nanoadjuvants feature the capability of all-stage tissue repair guidance and biofilm-responsive OI inhibition that can be routinely performed in all implant surgeries, providing a wide range of application prospects and commercial translational value.

Characteristics of healthy peri-implant tissues

This article forms part of the themed issue on dental implants, with the general dentist being the main intended reader and with particular relevance to primary care dental professionals. It aims to describe the various characteristics of the implant in health, address contemporary developments in implant dentistry and offer some novel insights on the prevention of peri-implant diseases. A healthy implant exhibits specific histological, clinical and radiographic characteristics. Understanding such aspects leads to proper diagnosis and measures to maintain tissue integrity and prevent the development and progression of peri-implant diseases. Moreover, internationally and widely accepted definitions and recommendations based on expert consensus have been put forward to guide day-to-day clinical practice. This information should provide general practitioners with the means necessary to achieve the best possible outcome for their patients.

Comparative effectiveness of interventions for the treatment of peri-implantitis: A systematic review with network meta-analysis

STATEMENT OF PROBLEM

Extensive research has been carried out on the various aspects of diagnosing and treating peri-implantitis. However, clinical guidelines for the management of peri-implantitis based on high quality evidence are lacking.

PURPOSE

The purpose of this systematic review with network meta-analysis was to analyze the current evidence on nonsurgical and surgical interventions for the treatment of peri-implantitis and synthesize clinical guidelines based on high quality evidence.

MATERIAL AND METHODS

A search was conducted for trials published in Medline, Scopus, PubMed, and Cochrane Central Register of Controlled Trials from inception until July 2023. The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023451056). A network meta-analysis was performed on data from randomized controlled trials that assessed nonsurgical and surgical interventions for the treatment of peri-implantitis. The interventions were ranked according to their efficacy using surface under the cumulative ranking (SUCRA) system. The grading of recommendations, assessment, development, and evaluations (GRADE) approach was used to assess the level of certainty of evidence.

RESULTS

A total of 45 articles were included in the quantitative analysis. The GRADE approach determined a moderate to high level of certainty of evidence. Among the nonsurgical interventions, mechanical debridement with adjunctive systemic antibiotics was significant in improving probing depth at 3 months and beyond 6 months, clinical attachment loss at 3 months, and clinical attachment loss beyond 6 months. Mechanical debridement with adjunctive topical antibiotics was significant in improving probing depth beyond 6 months, clinical attachment loss at 3 months, clinical attachment loss beyond 6 months, and radiographic bone loss beyond 6 months. Mechanical debridement with adjunctive photodynamic therapy was significant in improving probing depth beyond 6 months, clinical attachment loss at 3 months, clinical attachment loss beyond 6 months, and radiographic bone loss beyond 6 months. Mechanical debridement with adjunctive systemic antibiotics and photodynamic therapy was significant in improving probing depth beyond 6 months. Among surgical interventions, open flap debridement with implant surface decontamination and open flap debridement with decontamination and adjunctive photodynamic therapy were significant in improving probing depth at 3 months.

CONCLUSIONS

Mechanical debridement with adjunctive systemic antibiotics or photodynamic therapy results in improved clinical outcomes.

Biomechanical Effects of Ti-Base Abutment Height on the Dental Implant System: A Finite Element Analysis

This study aims to analyse, using a finite element analysis, the effects of Ti-base abutment height on the distribution and magnitude of transferred load and the resulting bone microstrain in the bone-implant system. A three-dimensional bone model of the mandibular premolar section was created with an implant placed in a juxta-osseous position. Three prosthetic models were designed: a 1 mm-high titanium-base (Ti-base) abutment with an 8 mm-high cemented monolithic zirconia crown was designed for model A, a 2 mm-high Ti-base abutment with a 7 mm-high crown for model B, and a 3 mm-high abutment with a 6 mm-high crown for model C. A static load of 150 N was applied to the central fossa at a six-degree angle with respect to the axial axis of the implant to evaluate the magnitude and distribution of load transfer and microstrain. The results showed a trend towards a direct linear association between the increase in the height of the Ti-base abutments and the increase in the transferred stress and the resulting microstrain to both the prosthetic elements and the bone/implant system. An increase in transferred stress and deformation of all elements of the system, within physiological ranges, was observed as the size of the Ti-base abutment increased.

Risk Factors for Early Implant Failure and Selection of Bone Grafting Materials for Various Bone Augmentation Procedures: A Narrative Review

Implant therapy is now an established treatment with high long-term success and survival rates. However, early implant failure, which occurs within one year of superstructure placement, occurs at a higher rate than late failure, which is represented by peri-implantitis caused by bacterial infection. Furthermore, various risk factors for early failure have been reported, including patient-related factors, such as systemic diseases, smoking, and bone quality and quantity, as well as surgery-related factors, such as surgeons' skill, osteogenesis technique, and selection of graft material, and implant-related factors, such as initial implant fixation and implant length diameter. Due to the wide variety of relevant factors reported, it is difficult to identify the cause of the problem. The purpose of this review is to discuss the risk factors associated with various types of bone augmentation which have a close causal relationship with early implant failure, and to determine the optimal bone grafting material for bone augmentation procedures to avoid early implant failure.

Maxillary Sinus Augmentation with Xenogenic Collagen-Retained Heterologous Cortico-Cancellous Bone: A 3-Year Follow-Up Randomized Controlled Trial

Sinus augmentation procedures have become a valuable solution for patients with posterior maxillary edentulism. The objective of this study was to explore the efficacy and safety of porcine xenograft with collagen supplementation as a potential alternative to autologous bone grafts in lateral sinus augmentation over a three-year follow-up period. Twelve patients, each with bilateral posterior maxillary edentulism, were enrolled and randomly allocated to receive either a porcine xenograft or an autologous graft. Comprehensive assessments, including clinical and radiographic evaluations, were conducted at specific intervals, including implant stability, marginal bone loss, prosthetic and biological complications, and patient preferences. The results demonstrated no significant differences between the two graft materials in terms of implant survival, marginal bone loss, and patient preferences after three years of follow-up. Only one implant was affected by peri-implantitis, and prosthesis-related complications were present in one patient possibly due to bruxism. In conclusion, these findings suggest that a porcine xenograft with collagen supplementation may be a viable alternative to an autograft in lateral sinus augmentation procedures. The high implant survival rate, minimal complications, and patient satisfaction indicate the potential clinical relevance of this graft material and should be further investigated to confirm these promising results.

Less marginal bone loss around bone-level implants restored with long abutments: A systematic review and meta-analysis

The aim of this study was to investigate the biological outcomes of bone-level implants restored with long vs. short abutments, with regard to the 'one abutment at one time' protocol. The systematic search was performed in five databases: MEDLINE (PubMed), EMBASE, Web of Science, Scopus, and CENTRAL for randomized controlled trials up to January 14, 2023. Data were collected for marginal bone loss, bleeding on probing, and probing pocket depth by two reviewers. As effect size measure, mean difference (MD), and risk ratio (RR) were used for continuous and categorical outcomes, R-statistics software was used for conducting statistical analyses. For quality and certainty assessment, Risk of Bias Tool 2, ROBINS-I, and GRADE approach were used. The search resulted in 4055 records without any duplicates. After title, abstract, and full-text analysis, eight articles were found eligible for inclusion. Bone-level and platform-switched implants presented less marginal bone loss after 6 months and 1 year as well, when long abutments were used (MD 0.63, 95% CI: [-0.16; 1.42]) and (MD 0.26, 95% CI: [-0.02; 0.53]). However, subgroup analysis revealed no difference in marginal bone loss when applying 'one abutment at one time' protocol (p = 0.973). Bleeding on probing and probing pocket depth presented similarly good results in both groups without almost any differences (RR 0.97, 95% CI: [0.76; 1.23]) and (MD -0.05, 95% CI: [-1.11; 1.01]). Longer abutments on bone-level implants seem to be a favorable choice for decreasing early marginal bone loss, irrespective of connection timing.

Photothermal-promoted multi-functional gallic acid grafted chitosan hydrogel containing tannic acid miniaturized particles for peri-implantitis

Peri-implantitis, a leading cause of implant failure, currently lacks effective therapeutic strategies. Given that bacterial infection and reactive oxygen species overabundance serve as primary pathogenic and triggering factors, respectively, an adhesive hydrogel has been created for in-situ injection. The hydrogel is a gallic acid-grafted chitosan (CS-GA) hydrogel containing tannic acid miniaturized particles (TAMP). This provides antibacterial and antioxidant properties. Therefore, this study aims to evaluate the potential role of this hydrogel in preventing and treating peri-implantitis via several experiments. It undergoes rapid formation within a span of over 20 s via an oxidative crosslinking reaction catalyzed by horseradish peroxidase and hydrogen peroxide, demonstrating robust adhesion, superior cell compatibility, and a sealing effect. Furthermore, the incorporation of TAMP offer photothermal properties to the hydrogel, enabling it to enhance the viability, migration, and antioxidant activity of co-cultured human gingival fibroblasts when subjected 0.5 W/cm2 808 nm near-infrared (NIR) irradiation. At higher irradiation power, the hydrogel exhibits progressive improvements in its antibacterial efficacy against Porphyromonas gingivalis and Fusobacterium nucleatum. It attains rates of 83.11 ± 5.42 % and 83.48 ± 6.855 %, respectively, under 1 W/cm2 NIR irradiation. In summary, the NIR-controlled CS-GA/TAMP hydrogel, exhibiting antibacterial and antioxidant properties, represents a promising approach for the prophylaxis and management of peri-implantitis.

Disparity in the Influence of Implant Provisional Materials on Human Gingival Fibroblasts with Different Phases of Cell Settlement: An In Vitro Study

The development of healthy peri-implant soft tissues is critical to achieving the esthetic and biological success of implant restorations throughout all stages of healing and tissue maturation, starting with provisionalization. The purpose of this study was to investigate the effects of eight different implant provisional materials on human gingival fibroblasts at various stages of cell settlement by examining initial cell attachment, growth, and function. Eight different specimens-bis-acrylic 1 and 2, flowable and bulk-fill composites, self-curing acrylic 1 and 2, milled acrylic, and titanium (Ti) alloy as a control-were fabricated in rectangular plates (n = 3). The condition of human gingival fibroblasts was divided into two groups: those in direct contact with test materials (contact experiment) and those in close proximity to test materials (proximity experiment). The proximity experiment was further divided into three phases: pre-settlement, early settlement, and late settlement. A cell culture insert containing each test plate was placed into a well where the cells were pre-cultured. The number of attached cells, cell proliferation, resistance to detachment, and collagen production were evaluated. In the contact experiment, bis-acrylics and composites showed detrimental effects on cells. The number of cells attached to milled acrylic and self-curing acrylic was relatively high, being approximately 70% and 20-30%, respectively, of that on Ti alloy. There was a significant difference between self-curing acrylic 1 and 2, even with the same curing modality. The cell retention ability also varied considerably among the materials. Although the detrimental effects were mitigated in the proximity experiment compared to the contact experiment, adverse effects on cell growth and collagen production remained significant during all phases of cell settlement for bis-acrylics and flowable composite. Specifically, the early settlement phase was not sufficient to significantly mitigate the material cytotoxicity. The flowable composite was consistently more cytotoxic than the bulk-fill composite. The harmful effects of the provisional materials on gingival fibroblasts vary considerably depending on the curing modality and compositions. Pre-settlement of cells mitigated the harmful effects, implying the susceptibility to material toxicity varies depending on the progress of wound healing and tissue condition. However, cell pre-settlement was not sufficient to fully restore the fibroblastic function to the normal level. Particularly, the adverse effects of bis-acrylics and flowable composite remained significant. Milled and self-curing acrylic exhibited excellent and acceptable biocompatibility, respectively, compared to other materials.

The influence of implant position and of prosthetic characteristics on the occurrence of peri-implantitis: a retrospective study on periapical radiographs

OBJECTIVE

The present retrospective study aimed to investigate the influence of malposition on the occurrence of peri-implantitis.

MATERIALS AND METHODS

The study included clinical records of systemically healthy patients with single and partial implant-supported rehabilitations and at least 1-year post-loading follow-up. The parameters collected included implant-related factors, patient-related factors, site-related factors, and prosthesis-related factors. The radiographic measurements were taken by using a dedicated software and the diagnosis of peri-implantitis was made based on all the available clinical and radiographic data. Descriptive statistics were provided for all variables. Following an exploratory approach, an implant-level analysis of factors influencing the occurrence of peri-implantitis was done through a multilevel multivariate logistic regression (mixed).

RESULTS

A total of 180 implants belonging to 90 subjects were randomly selected. Malposition showed no statistically significant association with the occurrence of peri-implantitis. According to the multi-level analysis, the parameters that were significantly associated with peri-implantitis included presence / history of periodontitis (OR = 5.945, 95% CI: 1.093 - 32.334, P = 0.039) and presence of an emergence profile angle ≥ 45° (OR = 9.094, 95% CI: 2.017 - 40.995, P = 0.005).

CONCLUSIONS

Implant malposition, as defined following Buser's criteria (2004), did not influence the occurrence of peri-implantitis in the selected cohort. Conversely, history of periodontitis and presence of a prosthetic emergence profile with an angle ≥ 45° were correlated to an increased risk of peri-implantitis.

Maxillary sinus membrane elevation and coagulum compared with maxillary sinus floor augmentation and a composite graft: A 1-year single-blinded randomized controlled trial

OBJECTIVE

The aim was to evaluate the 1-year implant outcome and patient-related outcome measures (PROMs) after maxillary sinus membrane elevation and coagulum (test) compared with maxillary sinus floor augmentation and a 1:1 ratio of autogenous bone graft from the buccal antrostomy and deproteinised porcine bone mineral (DPBM) (control).

MATERIALS AND METHODS

Forty patients (30 female, 10 male) with a mean age of 50 years (range 25-71 years) and an alveolar ridge height between 4 and 7 mm were randomly allocated to test or control. Outcome measures included survival of suprastructures and implants, implant stability quotient, health status of the peri-implant tissue, peri-implant marginal bone loss, frequency of complications and PROMs using Oral Health Impact Profile-14 combined with questionnaires assessing patient's perception of the peri-implant soft tissue, implant crown, function of the implant, and total implant treatment outcome using visual analogue scale. Mean differences were expressed with standard deviation and 95% confidence interval. Level of significance was 0.05.

RESULTS

All suprastructures and implants were well-functioning after 1-year of functional implant loading. No significant difference in any of the applied outcome measures was observed between test and control. Both treatments revealed high patient satisfaction scores and significant improvement in oral health-related quality of life.

CONCLUSION

There were no significant differences in implant outcome and PROMs between test and control, after 1-year of functional implant loading. Neither of the treatments can therefore be considered better than the other. Thus, long-term randomized controlled trials are needed before definitive conclusions can be provided about the two treatment modalities.

Electron Microscopy (EM) Analysis of Collagen Fibers in the Peri-Implant Soft Tissues around Two Different Abutments

The design of the implant prosthesis-abutment complex appears crucial for shaping healthy and stable peri-implant soft tissues. The aim of the present animal study was to compare two implants with different healing abutment geometries: a concave design (TEST) and a straight one (CTRL). Transmission electron microscopy (TEM) was used to quantify the three-dimensional topography and morphological properties of collagen at nanoscale resolution. 2 swine were included in the experiment and 6 implants per animal were randomly placed in the left or right hemimandible in either the physiologically mature bone present between the lower canine and first premolar or in the mandibular premolar area, within tooth extraction sites. Each CTRL implant was positioned across from its respective TEST implant on the other side of the jaw. After 12 weeks of healing, 8 specimens (4 CTRL and 4 TEST) were retrieved and prepared for histological and TEM analysis. The results showed a significantly higher percentage of area covered by collagen bundles and average bundle size in TEST implants, as well as a significant decrease in the number of longitudinally oriented bundles with respect to CTRL implants, which is potentially due to the larger size of TEST bundles. These data suggest that a concave transmucosal abutment design serves as a scaffold, favoring the deposition and growth of a well-organized peri-implant collagen structure over the implant platform in the early healing phase, also promoting the convergence of collagen fibers toward the abutment collar.

Spontaneous regeneration of keratinized tissue at implants and teeth

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 (T0 ) and after 12 weeks (T1 ). Following healing, the animals were euthanized, and the specimens were histologically processed. Descriptive statistical analyses were performed.

RESULTS

Clinical measurements revealed that at T1 , 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.

The Potential Value of Probiotics after Dental Implant Placement

Dental implantation is currently the optimal solution for tooth loss. However, the health and stability of dental implants have emerged as global public health concerns. Dental implant placement, healing of the surgical site, osseointegration, stability of bone tissues, and prevention of peri-implant diseases are challenges faced in achieving the long-term health and stability of implants. These have been ongoing concerns in the field of oral implantation. Probiotics, as beneficial microorganisms, play a significant role in the body by inhibiting pathogens, promoting bone tissue homeostasis, and facilitating tissue regeneration, modulating immune-inflammatory levels. This review explores the potential of probiotics in addressing post-implantation challenges. We summarize the existing research regarding the importance of probiotics in managing dental implant health and advocate for further research into their potential applications.

Influence of Periodontal Status and Prosthetic Treatment on Survival and Success Rates in Implant Therapy: A 5-Year Retrospective Follow-Up Study

The objective of the present study was to evaluate the 5-year outcome of dental implant therapy and assess the survival, success, and biological and technical complications. A periodontal and prosthetic-oriented evaluation was conducted on the variables that can influence the long-term predictability of implant therapy. A total of 615 patients and 1427 dental implants from a private clinic (MedArtis Dent, Cluj-Napoca, Romania) were enrolled in the study. The study was a longitudinal cohort with data collected retrospectively from physical/digital dental records in combination with a cross-sectional clinical/radiological examination. Results showed that periodontal diagnosis at baseline had a significant impact on the marginal bone loss prediction. Data showed that the cylindrical implant with an internal 45° medium taper connection experienced a higher rate of bone resorption compared to the tapered implant with the 5° internal connection. Screw-retained restorations and overdentures showed a statistical decrease in the marginal bone level height when compared to the cemented restorations. Data from our study suggest that not only is there a powerful association between recall visits and the rate of complications in dental implant treatment, but a lack of professional maintenance predicts a higher bone level loss during the 5-year interval.

Influence of antiresorptive/antiangiogenic therapy on the extension of experimentally induced peri-implantitis lesions

OBJECTIVES

To investigate the extension of experimentally induced peri-implantitis lesions under various antiresorptive and antiangiogenic medications.

MATERIAL AND METHODS

Fourty-eight albino rats had randomly received the following medications (dual application, n = 8 each): (1) amino-bisphosphonate (zoledronate) (Zo), (2) RANKL inhibitor (denosumab) (De), (3) antiangiogenic (bevacizumab) (Be), (4) Zo+Be, (5) De+Be, or (6) no medication (Co). Ligature- and lipopolysaccharide-induced peri-implantitis lesions were established at 2 maxillary implants over a period of 16 weeks. Histological (e.g., apical extension and surface area of the inflammatory cell infiltrate-aICT, ICT; defect length; defect width; CD68 positive cells) and bone micromorphometric (μCT) outcomes were assessed. The animal was defined as a statistical unit.

RESULTS

A total of n = 38 animals (Zo = 6, De = 6, Be = 8, Zo + Be = 6, De + Be = 5, Co = 7) were analyzed. ICT's were commonly marked by a positive CD68 antigen reactivity. Comparable median aICT (lowest-Zo: 0.53 mm; highest-Be: 1.22 mm), ICT (lowest-De + Be: 0.00 mm2; highest-Co: 0.49 mm2), defect length (lowest-Zo: 0.90 mm; highest-Co: 1.93 mm) and defect width (lowest-De+Be: 1.27 mm; highest-Be: 1.80 mm) values were noted in all test and control groups. Within an inner (diameter: 0.8 mm) cylindric volume of interest, the bone microstructure did not significantly differ between groups.

CONCLUSIONS

The present analysis did not reveal any marked effects of various antiresorptive/ antiangiogenic medications on the extension of experimentally induced peri-implantitis lesions.

CLINICAL RELEVANCE

The extension of peri-implantitis lesions may not be facilitated by the antiresorptive and antiangiogenic medications investigated.

Biocompatibility, Surface Morphology, and Bacterial Load of Dental Implant Abutments following Decontamination Protocols: An In-Vitro Study

The long-term success of dental implant rehabilitation depends significantly on proper peri-implant soft tissue integration. Therefore, decontamination of abutments prior to their connection to the implant is beneficial to enhance soft tissue attachment and to aid in maintaining marginal bone around the implant. Consequently, different implant abutment decontamination protocols were evaluated regarding biocompatibility, surface morphology, and bacterial load. The protocols evaluated were autoclave sterilization, ultrasonic washing, steam cleaning, chlorhexidine chemical decontamination, and sodium hypochlorite chemical decontamination. The control groups included: (1) implant abutments prepared and polished in a dental lab without decontamination and (2) unprepared implant abutments obtained directly from the company. Surface analysis was performed using scanning electron microscopy (SEM). Biocompatibility was evaluated using XTT cell viability and proliferation assays. Biofilm biomass and viable counts (CFU/mL) (n = 5 for each test) were used for surface bacterial load evaluation. Surface analysis revealed areas of debris and accumulation of materials, such as iron, cobalt, chromium, and other metals, in all abutments prepared by the lab and with all decontamination protocols. Steam cleaning was the most efficient method for reducing contamination. Chlorhexidine and sodium hypochlorite left residual materials on the abutments. XTT results showed that the chlorhexidine group (M = 0.7005, SD = 0.2995) had the lowest values (p < 0.001) (autoclave: M = 3.6354, SD = 0.1510; ultrasonic: M = 3.4077, SD = 0.3730; steam: M = 3.2903, SD = 0.2172; NaOCl: M = 3.5377, SD = 0.0927; prep non-decont.: M = 3.4815, SD = 0.2326; factory: M = 3.6173, SD = 0.0392). Bacterial growth (CFU/mL) was high in the abutments treated with steam cleaning and ultrasonic bath: 2.93 × 10⁹, SD = 1.68 × 10¹² and 1.83 × 10⁹, SD = 3.95 × 10¹⁰, respectively. Abutments treated with chlorhexidine showed higher toxicity to cells, while all other samples showed similar effects to the control. In conclusion, steam cleaning seemed to be the most efficient method for reducing debris and metallic contamination. Bacterial load can be reduced using autoclaving, chlorhexidine, and NaOCl.

Current Status of Peri-Implant Diseases: A Clinical Review for Evidence-Based Decision Making

BACKGROUND

the prevalence of peri-implant diseases is constantly growing, particularly with the increasing use of dental implants. As such, achieving healthy peri-implant tissues has become a key challenge in implant dentistry since it considers the optimal success paradigm. This narrative review aims to highlight the current concepts regarding the disease and summarize the available evidence on treatment approaches clarifying their indications for usage following the World Workshop on the Classification of Periodontal and Peri-implant Diseases (2017).

METHODS

we reviewed the recent literature and conducted a narrative synthesis of the available evidence on peri-implant diseases.

RESULTS

scientific evidence on case definitions, epidemiology, risk factors, microbiological profile, prevention, and treatment approaches for peri-implant diseases were summarized and reported.

CONCLUSIONS

although there are numerous protocols for managing peri-implant diseases, they are diverse and nonstandardized, with no consensus on the most effective, leading to treatment confusion.

Gear-shaped carbonate apatite granules with a hexagonal macropore for rapid bone regeneration

Synthetic bone grafts are in high demand owing to increased age-related bone disorders in the global aging population. Here, we report fabrication of gear-shaped granules (G-GRNs) for rapid bone healing. G-GRNs possessed six protrusions and a hexagonal macropore in the granular center. These were composed of carbonate apatite, i.e., bone mineral, microspheres with ∼1-μm micropores in the spaces between the microspheres. G-GRNs formed new bone and blood vessels (both on the granular surface and within the macropores) 4 weeks after implantation in the rabbit femur defects. The formed bone structure was similar to that of cancellous bone. The bone percentage in the defect recovered to that in a normal rabbit femur at week-4 post-implantation, and the bone percentage remained constant for the following 8 weeks. Throughout the entire period, the bone percentage in the G-GRN-implanted group was ∼10% higher than that of the group implanted with conventional carbonate apatite granules. Furthermore, a portion of the G-GRNs resorbed at week-4, and resorption continued for the following 8 weeks. Thus, G-GRNs are involved in bone remodeling and are gradually replaced with new bone while maintaining a suitable bone level. These findings provide a basis for the design and fabrication of synthetic bone grafts for achieving rapid bone regeneration.

Comparing the Long-Term Success Rates of Tooth Preservation and Dental Implants: A Critical Review

Implant therapy is considered a predictable, safe, and reliable rehabilitation method for edentulous patients in most clinical scenarios. Thus, there is a growing trend in the indications for implants, which seems attributable not only to their clinical success but also to arguments such as a more "simplified approach" based on convenience or the belief that dental implants are as good as natural teeth. Therefore, the objective of this critical literature review of observational studies was to discuss the evidence concerning the long-term survival rates and treatment outcomes, comparing endodontically or periodontally treated teeth with dental implants. Altogether, the evidence suggests that the decision between keeping a tooth or replacing it with an implant should carefully consider the condition of the tooth (e.g., amount of remaining tooth and degree of attachment loss and mobility), systemic disorders, and patient preference. Although observational studies revealed high success rates and long-term survival of dental implants, failures and complications are common. For this reason, attempts should be made to first save maintainable teeth over the long-term, instead of immediately replacing teeth with dental implants.

Influence of different mucosal phenotype on early and long-term marginal bone loss around implants: a systematic review and meta-analysis

OBJECTIVES

To investigate the influence of different mucosal phenotypes on peri-implant marginal bone loss.

MATERIALS AND METHODS

The search was conducted in five databases including PubMed, Embase, Cochrane, Scopus, and Web of Science (until 1st Sept. 2022) to identify relevant clinical studies. Potentially relevant journals were also manually searched. Two reviewers independently screened studies, extracted data, and evaluated the quality of the studies. Prospective clinical trials and observational studies investigating peri-implant marginal bone loss in thick-mucosa and thin-mucosa groups were included.

RESULTS

A total of 14 studies were included in this systematic review. Results of the meta-analysis revealed a weighted mean difference of 0.38 mm for marginal bone loss between thick- and thin-mucosa groups (95% confidence interval = 0.02-0.74, P = 0.002). Statistical significance existed in short-term (follow-up ≤ 1 year) data (WMD = 0.41 mm, 95%CI = 0.11-0.70, P = 0.007), but not in long term (follow-up ≥ 3 y) data (WMD = 0.17 mm, 95%CI = - 0.02-0.36, P = 0.07). Survival rate revealed no difference between thick and thin mucosa groups. In subgroup analyses, a positive association between thick mucosa and less marginal bone loss was found in the non-submerged group, cement-retained group, and bone-level group.

CONCLUSIONS

A significantly less marginal bone loss occurred in implants with thick mucosa than with thin mucosa in the short term, whereas no significant difference was observed in the long term. Due to the substantial heterogeneity and limited long-term data, further high-quality evidence is warranted to confirm the results.

CLINICAL RELEVANCE

Clinicians are advised to use caution in treating patients with thin mucosa and adhere closely to indications and protocols to minimize marginal bone loss.

Digital evaluation of facial peri-implant mucosal thickness and its impact on dental implant aesthetics

OBJECTIVE

The aim of the present study was to describe and compare the features of the buccal peri-implant mucosa to natural gingiva in the aesthetic area.

MATERIAL AND METHODS

Forty-nine periodontally healthy patients were included in this cross-sectional study. Mucosal and gingival dimensions at the mid-facial aspect were evaluated clinically and radiographically. Color assessments were performed using a reflectance spectrophotometer, and patient aesthetic satisfaction was further checked.

RESULTS

Implant sites revealed significant thicker mucosa when compared to tooth sites both at 1.5 (p < 0.001) and 3 mm (p < 0.001) apical to the mucosal margin. Both conventional and digital methods presented a good reliability. The spectrophotometric data revealed a statistically significant color difference between the peri-implant mucosa and the gingiva. However, there was no further significant relation between these color changes and the mucosal thickness.

CONCLUSIONS

Peri-implant mucosa revealed a darkish, greenish, and bluish discoloration when compared to the gingiva. More satisfactory patient´s aesthetic evaluation was reported in sites with thicker and comparatively lighter mucosa when compared to the adjacent dentition.

CLINICAL RELEVANCE

This article focuses on variables affecting color stability and aesthetics around dental implants. These can be assessed to identify the need for peri-implant phenotypic modification.

Implant prosthodontic design as a predisposing or precipitating factor for peri-implant disease: A review

Over the past decade, emerging evidence indicates a strong relationship between prosthetic design and peri-implant tissue health. The objective of this narrative review was to evaluate the evidence for the corresponding implant prosthodontic design factors on the risk to peri-implant tissue health. One of the most important factors to achieve an acceptable implant restorative design is the ideal implant position. Malpositioned implants often result in a restorative emergence profile at the implant-abutment junction that can restrict the access for patients to perform adequate oral hygiene. Inadequate cleansability and poor oral hygiene has been reported as a precipitating factors to induce the peri-implant mucositis and peri-implantitis and are influenced by restorative contours. The implant-abutment connection, restorative material selection and restoration design are also reported in the literature as having the potential to influence peri-implant sort tissue health.

Xenogeneic collagen matrix versus free gingival graft for augmenting keratinized mucosa around posterior mandibular implants: a randomized clinical trial

OBJECTIVES

To assess the clinical efficacy of xenogeneic collagen matrix (XCM) plus apically positioned flap (APF) in augmenting the keratinized mucosa (KM) width (KMW) and thickness (KMT) around posterior mandibular implants and compare it with free gingival graft (FGG) plus APF.

MATERIAL AND METHODS

Thirty patients with KMW ≤ 2 mm in the posterior mandibular implant site were randomly allocated to the FGG group (FGG plus APF) or the XCM group (XCM plus APF). Clinical assessments, including KMW and KMT, shrinkage rate of established KM, and peri-implant soft tissue health, were evaluated during a 6-month follow-up. Additionally, the esthetic outcomes and patient-reported postoperative morbidity were investigated.

RESULTS

At 6 months, the KMW measured 3.60 ± 0.79 mm in the FGG group and 3.28 ± 0.96 mm in the XCM group (p = 0.186). Both groups showed a tendency for graft contraction (FGG, 42.11%; XCM, 53.22%). The KMT measured 1.24 ± 0.34 mm in the FGG group and 0.95 ± 0.29 mm in the XCM group, with statistical difference (p = 0.002). No difference in the peri-implant soft tissue health was observed between the two groups (p > 0.05), but the esthetic outcomes were better in the XCM group (p < 0.05).

CONCLUSIONS

XCM plus APF rendered a similar clinical efficacy in augmenting KMW as that with FGG plus APF, but with higher shrinkage. XCM plus APF was inferior with respect to FGG plus APF in augmenting KMT. The esthetic outcomes were better with XCM plus APF than FGG plus APF. Clinical relevance XCM plus APF graft was inferior with respect to FGG plus APF in augmenting KMT.

TRIAL REGISTRATION

Trial registration number: ChiCTR2200058027 and date: 03/27/2022.

Accuracy of Augmented Reality-Assisted Navigation in Dental Implant Surgery: Systematic Review and Meta-analysis

BACKGROUND

The novel concept of immersive 3D augmented reality (AR) surgical navigation has recently been introduced in the medical field. This method allows surgeons to directly focus on the surgical objective without having to look at a separate monitor. In the dental field, the recently developed AR-assisted dental implant navigation system (AR navigation), which uses innovative image technology to directly visualize and track a presurgical plan over an actual surgical site, has attracted great interest.

OBJECTIVE

This study is the first systematic review and meta-analysis study that aimed to assess the accuracy of dental implants placed by AR navigation and compare it with that of the widely used implant placement methods, including the freehand method (FH), template-based static guidance (TG), and conventional navigation (CN).

METHODS

Individual search strategies were used in PubMed (MEDLINE), Scopus, ScienceDirect, Cochrane Library, and Google Scholar to search for articles published until March 21, 2022. This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. Peer-reviewed journal articles evaluating the positional deviations of dental implants placed using AR-assisted implant navigation systems were included. Cohen d statistical power analysis was used to investigate the effect size estimate and CIs of standardized mean differences (SMDs) between data sets.

RESULTS

Among the 425 articles retrieved, 15 articles were considered eligible for narrative review, 8 articles were considered for single-arm meta-analysis, and 4 were included in a 2-arm meta-analysis. The mean lateral, global, depth, and angular deviations of the dental implant placed using AR navigation were 0.90 (95% CI 0.78-1.02) mm, 1.18 (95% CI 0.95-1.41) mm, 0.78 (95% CI 0.48-1.08) mm, and 3.96° (95% CI 3.45°-4.48°), respectively. The accuracy of AR navigation was significantly higher than that of the FH method (SMD=-1.01; 95% CI -1.47 to -0.55; P<.001) and CN method (SMD=-0.46; 95% CI -0.64 to -0.29; P<.001). However, the accuracies of the AR navigation and TG methods were similar (SMD=0.06; 95% CI -0.62 to 0.74; P=.73).

CONCLUSIONS

The positional deviations of AR-navigated implant placements were within the safety zone, suggesting clinically acceptable accuracy of the AR navigation method. Moreover, the accuracy of AR implant navigation was comparable with that of the highly recommended dental implant-guided surgery method, TG, and superior to that of the conventional FH and CN methods. This review highlights the possibility of using AR navigation as an effective and accurate immersive surgical guide for dental implant placement.

On Peri-Implant Bone Loss Theories: Trying To Piece Together the Jigsaw

This review aims to explore the plausibility of new theories on the etiopathogenesis of marginal bone loss (MBL) and peri-implantitis (PI) and to discuss possible underlying pathogenic mechanisms. The former concept of osteointegration of dental implants can now be conceptualized as a foreign body response histologically characterized by a bony demarcation in combination with chronic inflammation. Different risk factors can provoke additional inflammation and, therefore, pro-inflammatory cytokine release in soft tissues and bone, leading to an overpass of the threshold of peri-implant bone defensive and regenerative capacity. Progressive bone loss observed in MBL and PI is ultimately due to a localized imbalance in the receptor activator of nuclear factor kappaB ligand (RANKL)/Receptor activator of nuclear factor κ B (RANK)/osteoprotegerin (OPG) pathway in favor of increased catabolic activity. The genetic background and the severity and duration of the risk factors could explain differences between individuals in the threshold needed to reach an imbalanced scenario. MBL and PI pathogenesis could be better explained by the "inflammation-immunological balance" theory rather than a solely "infectious disease" conception. The link between the effect of biofilm and other risk factors leading to an imbalanced foreign body response lies in osteoclast differentiation and activation pathways (over)stimulation.

Early marginal bone loss around dental implants to define success in implant dentistry: A retrospective study

PURPOSE

The aim of this study was to establish an objective criterion in terms of marginal bone level (MBL) to know the prognosis of an implant.

MATERIALS AND METHODS

A group of 176 patients in whom 590 implants were placed were included in this retrospective study. Patients older than 18 years, presenting either Kennedy class I or II edentulous section, or totally edentulous at least in one of the dental arches were included in this study. Those with any type of disturbance able to alter bone metabolism or with nontreated periodontal disease were excluded. Data on radiographic MBL at loading, 6 and 18 months later, age, gender, smoking habits, history of periodontitis, bone substratum, implant, and prosthetic features were recorded. Nonparametric receiver operating curves (ROC) were constructed for the MBL at 18 months in order to establish a distinction among high bone loser (HBL) and low bone loser (LBL) implants. Differences as a function of main variables were also determined, particularly abutment height and periodontal disease.

RESULTS

HBL implants lost at least 0.48 mm of MBL 6 months after loading; they reached at least 2 mm of MBL 18 months after loading. MBL rate followed a nonlinear trend, except in implants restored over long prosthetic abutments and in patients with history of severe periodontitis; in whom the rate of MBL over the time was nearly zero.

CONCLUSION

Implants that lose more than 0.5 mm of marginal bone 6 months after loading are at great risk of not being radiographically successful anymore. Therefore, 0.5 mm of MBL is proposed as a distinctive and objective criterion of success in Implant Dentistry within a 6-month follow-up period. A prosthetic abutment height ≥2 mm resulted the most protective factor in the peri-implant bone maintenance.

Connective tissue graft versus xenogeneic collagen matrix for soft tissue augmentation at implant sites: a randomized-controlled clinical trial

OBJECTIVES

The purpose of this randomized clinical trial (RCT) is to compare xenogeneic collagen matrix (XCM) versus subepithelial connective tissue graft (SCTG) to increase soft tissue thickness at implant site.

MATERIALS AND METHODS

The study was a randomized, parallel-group controlled investigation. Thirty patients underwent buccal soft tissue thickness augmentation at the stage of implant placement by two different methods: SCTG (control group) and XCM (test group). Primary outcome was the amount of buccal soft tissue thickness gain, 3 months after the intervention. Secondary outcomes were the operation time, the amount of keratinized mucosa (KM), pain syndrome (PS), and patients' quality of life (QL). Histologic evaluation was also performed.

RESULTS

The amount of soft tissue thickness gain was 1.55±0.11 mm in SCTG group, and 1.18±0.11mm in XCM group. The difference between the SCTG and XCM was -0.366 (-0.66 to -0.07; p=0.016). Operation time with XCM was 8.4 (3.737 to 13.06) min shorter than that with the SCTG (p=0.001). KT, PS, and QL for both groups were not statistically significantly different at any time point (p>0.05). At histological examination, the general picture in both groups was similar. No significant differences between the studied groups in most indices, except for the average and maximum formation thickness, cellularity of the basal, mitotic activity and also maximum length of rete ridges.

CONCLUSION

Within limitations, this study demonstrates that the use of SCTG provides a statistically significant superior soft tissue thickness gain than XCM for soft tissue augmentation procedures around implants.

CLINICAL RELEVANCE

XCM can be used as the method of choice for increasing the thickness of soft tissues.