Background: Whether a minimal width of keratinized mucosa (KM) is required to maintain peri-implant tissue health has been a topic of interest. This systematic review and meta-analysis aims to investigate the effect of KM on various peri-implant health-related parameters.Methods: An electronic search of five databases (from 1965 to October 2012) and a hand search of peer-reviewed journals for relevant articles were performed. Human cross-sectional or longitudinal studies with data on the relationship between the amount of KM around dental implants and various peri-implant parameters, with a follow-up period of at least 6 months, were included.Results: Eleven studies, seven cross-sectional and four longitudinal, were included. Weighted mean difference (WMD) and confidence interval (CI) were calculated with meta-analyses for each clinical parameter. The results showed statistically significant differences in plaque index (PI) and modified PI (WMD = −0.27, 95% CI = −0.43 to −0.11), modified gingival index (m...

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The Significance of Keratinized Mucosa on Implant Health: A Systematic Review

The invention of computerized axial tomography (now known as computerized tomography) and developments of interactive software to allow virtual planning, with the aim to guide the surgery precisely toward a specific target, has dramatically improved general, as well as oral, surgery. Virtual dental implant planning allows for a prosthetically driven approach, resulting in the best possible design of the prosthesis, better esthetics, optimized occlusion and loading. This approach has also changed the surgical paradigm of using extensive flaps to obtain a proper view of the surgical area because flapless implant surgery, with or without immediate loading, has become more predictable. Two types of guided implant surgery protocols – static and dynamic – are described in the literature. The static approach, better known as computer-guided surgery, refers to the use of a tissue-supported surgical template. This reproduces the virtual implant position directly from computerized tomographic data and this information can be converted to guide templates to be used during surgery, with or without raising a mucoperiosteal flap. Dynamic guided surgery, also called navigation, reproduces the virtual implant position directly from computerized tomographic data and uses motion-tracking technology to guide the implant osteotomy preparation. As the technology developed further, different levels of evidence were presented that showed various degrees of accuracy. Several protocols for guided surgery are available in the literature and are distinguished by different guide production techniques, methods of support and drilling/placement protocols. Currently, implant planning software using cone-beam computerized tomography data has made it possible to plan the optical implant position virtually the optimal implant position, taking the surrounding vital anatomic structures and future prosthetic requirements into consideration. This paper summarizes the evolution and ongoing trends in digital and virtual planning and in implant surgery. The purpose of this overview was to clarify the different concepts in guided surgery and their respective advantages, disadvantages and limitations. The outcome of guided surgery is assessed in terms of implant survival, precision and complications. Clinical cases are given to demonstrate briefly the workflow and clinical guidelines for safe use of these approaches.

Current state of the art of computer-guided implant surgery.

OBJECTIVE To review the dental literature in terms of soft tissue augmentation procedures and their influence on peri-implant health or disease in partially and fully edentulous patients. METHODS A MEDLINE search from 1966 to 2016 was performed to identify controlled clinical studies comparing soft tissue grafting versus no soft tissue grafting (maintenance) or two types of soft tissue grafting procedures at implant sites. The soft tissue grafting procedures included either an increase of keratinized tissue or an increase of the thickness of the peri-implant mucosa. Studies reporting on the peri-implant tissue health, as assessed by bleeding or gingival indices, were included in the review. The search was complemented by an additional hand search of all selected full-text articles and reviews published between 2011 and 2016. The initial search yielded a total number of 2,823 studies. Eligible studies were selected based on the inclusion criteria (finally included: four studies on gain of keratinized tissue; six studies on gain of mucosal thickness) and quality assessments conducted. Meta-analyses were applied whenever possible. RESULTS Soft tissue grafting procedures for gain of keratinized tissue resulted in a significantly greater improvement of gingival index values compared to maintenance groups (with or without keratinized tissue) [n = 2; WMD = 0.863; 95% CI (0.658; 1.067); p < .001]. For final marginal bone levels, statistically significant differences were calculated in favor of an apically positioned flap (APF) plus autogenous grafts versus all control treatments (APF alone; APF plus a collagen matrix; maintenance without intervention [with or without residual keratinized tissue]) [n = 4; WMD = -0.175 mm; 95% CI: (-0.313; -0.037); p = .013]. Soft tissue grafting procedures for gain of mucosal thickness did not result in significant improvements in bleeding indices over time, but in significantly less marginal bone loss over time [WMD = 0.110; 95% CI: 0.067; 0.154; p < .001] and a borderline significance for marginal bone levels at the study endpoints compared to sites without grafting. CONCLUSIONS Within the limitations of this review, it was concluded that soft tissue grafting procedures result in more favorable peri-implant health: (i) for gain of keratinized mucosa using autogenous grafts with a greater improvement of bleeding indices and higher marginal bone levels; (ii) for gain of mucosal thickness using autogenous grafts with significantly less marginal bone loss.

https://www.zora.uzh.ch/id/eprint/156823/2/Thoma_et_al-2018-Clinical_Oral_Implants_Research_pub.pdf

Effects of soft tissue augmentation procedures on peri-implant health or disease: A systematic review and meta-analysis.

Aim
To review the dental literature in terms of efficacy of soft tissue augmentation procedures around dental implants and in partially edentulous sites.

Methods
A Medline search was performed for human studies augmenting keratinized mucosa (KM) and soft tissue volume around implants and in partially edentulous areas. Due to heterogeneity in between the studies, no meta-analyses could be performed.

Results
Nine (KM) and eleven (volume) studies met the inclusion criteria. An apically positioned flap/vestibuloplasty (APF/V) plus a graft material [free gingival graft (FGG)/subepithelial connective tissue graft (SCTG)/collagen matrix (CM)] resulted in an increase of keratinized tissue (1.4–3.3 mm). Statistically significantly better outcomes were obtained for APF/V plus FGG/SCTG compared with controls (APF/V alone; no treatment) (p < 0.05). For surgery time and patient morbidity, statistically significantly more favourable outcomes were reported for CM compared to SCTGs (p < 0.05) in two randomized controlled clinical trials (RCTs), even though rendering less keratinized tissue. SCTGs were the best-documented method for gain of soft tissue volume at implant sites and partially edentulous sites. Aesthetically at immediate implant sites, better papilla fill and higher marginal mucosal levels were obtained using SCTGs compared to non-grafted sites.

Conclusions
An APF/V plus FGG/SCTG was the best-documented and most successful method to increase the width of KM. APF/V plus CM demonstrated less gain in KM, but also less patient morbidity and surgery time compared to APF/V plus SCTG based on two RCTs. Autogenous grafts (SCTG) rendered an increase in soft tissue thickness and better aesthetics compared to non-grafted sites.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jcpe.12220

Efficacy of soft tissue augmentation around dental implants and in partially edentulous areas: a systematic review

OBJECTIVES

This narrative review was prepared for the 2017 World Workshop of the American Academy of Periodontology and European Federation of Periodontology to address key questions related to the clinical condition of peri-implant mucositis, including: 1) the definition of peri-implant mucositis, 2) conversion of peri-implant health to the biofilm-induced peri-implant mucositis lesion, 3) reversibility of peri-implant mucositis, 4) the long-standing peri-implant mucositis lesion, 5) similarities and differences between peri-implant mucositis at implants and gingivitis at teeth, and 6) risk indicators/factors for peri-implant mucositis.

METHODS

A literature search of MEDLINE (PubMed) and The Cochrane Library up to and including July 31, 2016, was carried out using the search strategy (peri-implant[All Fields] AND ("mucositis"[MeSH Terms] OR "mucositis"[All Fields])) OR (periimplant[All Fields] AND mucosits[All Fields]). Prospective, retrospective, and cross-sectional studies and review papers that focused on risk factors/indicators for peri-implant mucositis as well as experimental peri-implant mucositis studies in animals and humans were included.

FINDINGS

Peri-implant mucositis is an inflammatory lesion of the soft tissues surrounding an endosseous implant in the absence of loss of supporting bone or continuing marginal bone loss. A cause-and-effect relationship between experimental accumulation of bacterial biofilms around titanium dental implants and the development of an inflammatory response has been demonstrated. The experimental peri-implant mucositis lesion is characterized by an inflammatory cell infiltrate present within the connective tissue lateral to the barrier epithelium. In long-standing peri-implant mucositis, the inflammatory cell infiltrate is larger in size than in the early (3-week) experimental peri-implant mucositis lesion. Biofilm-induced peri-implant mucositis is reversible at the host biomarker level once biofilm control is reinstituted. Reversal of the clinical signs of inflammation may take longer than 3 weeks. Factors identified as risk indicators for peri-implant mucositis include biofilm accumulation, smoking, and radiation. Further evidence is required for potential risk factors, including diabetes, lack of keratinized mucosa, and presence of excess luting cement.

CONCLUSIONS

Peri-implant mucositis is caused by biofilm accumulation which disrupts the host-microbe homeostasis at the implant-mucosa interface, resulting in an inflammatory lesion. Peri-implant mucositis is a reversible condition at the host biomarker level. Therefore, the clinical implication is that optimal biofilm removal is a prerequisite for the prevention and management of peri-implant mucositis. An understanding of peri-implant mucositis is important because it is considered a precursor for peri-implantitis.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jcpe.12953

Peri-implant mucositis.

The question of whether a sufficient amount of keratinized tissue around natural teeth or dental implants is necessary for long-term periodontal or peri-implant health, as well as the question of what has to be considered ‘sufficient,’ are still controversial (Lang & Loe 1972; Krekeler et al. 1985; Wennstrom 1987; Wennstrom et al. 1994; Heckmann et al. 2004).

More than 35 years ago, Lang & Loe (1972) found better periodontal health in teeth, which yielded at least 2 mm of keratinized gingiva with at least 1 mm being attached, compared to teeth with < 2 mm of keratinized gingiva. Although the latter findings have been challenged by subsequent studies (Miyasato et al. 1977; Wennstrom & Lindhe 1983a; Kennedy et al. 1985; Wennstrom 1987), a width of 2 mm of keratinized gingiva has been considered clinically desirable to provide an appropriate soft-tissue seal around natural teeth since then.

Taking into account the considerable differences between the soft-tissue interface of dental implants and that of natural teeth, the questions arise, if peri-implant keratinized mucosa is necessary or at least beneficial for peri-implant soft-tissue health, and if the same 2 mm threshold recommended for natural teeth also applies to dental implants.

If the amount of keratinized mucosa has an impact on peri-implant health, special measures would be required in patients with insufficient amounts of keratinized mucosa during maintenance therapy including specific oral hygiene instructions and closer maintenance intervals. Moreover, surgical procedures aiming at widening the keratinized tissue and increasing the vestibular depth may be indicated.

Although it has been demonstrated that dental implants are successful in the treatment of edentulous jaws with fixed or removable prostheses (Ferrigno et al. 2002), augmentation of keratinized mucosa or vestibular depth may especially be required in the edentulous mandible, in which moderate to severe ridge resorption may have lead to reduced vestibular depth and a lack of keratinized mucosa.

Numerous techniques to do so have been described, including free gingival grafts from the palate with or without combination of a vestibuloplasty (Edlan 1973; Buser 1987; Simons & Baima 1994; Han et al. 1995). Depending on the technique applied, some of these procedures may pose a significant challenge for the patient, especially when elderly or medically compromised.

Accordingly, it would be of great importance both for clinicians and patients to better understand the significance of peri-implant keratinized tissue for long-term soft-tissue health and stability, in order to better assess the need for additional surgical procedures or special considerations during maintenance therapy. However, as of today, the literature is inconclusive, contradictory and lacks long-term human data.

Therefore, the purpose of this study was to investigate the necessity of peri-implant keratinized mucosa as a prerequisite for long-term soft-tissue health and stability over a period of 5 years.

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Five-year evaluation of the influence of keratinized mucosa on peri-implant soft-tissue health and stability around implants supporting full-arch mandibular fixed prostheses.

This report summarizes the statements and clinical recommendations for implant loading protocols as per consensus agreement among the participants at the 5th ITI Consensus Conference.Group 4 was composed of participants from 13 dif-ferent countries and of various specialties in dental medicine. Prior to the conference, scientific evidence on conventional, early, and immediate implant loading

Consensus statements and clinical recommendations for implant loading protocols.

Purpose The aim of this study was to systematically review the evidence for immediate implant loading in partially edentulous patients with extended edentulous sites and evaluate potential treatment modifiers. Materials and methods An electronic search was performed in Medline, Embase, and Central to identify studies investigating the outcome of implants subjected to immediate loading (IL) (less than 1 week), early loading (EL) (1 week to 2 months), or conventional loading (CL) (more than 2 months) with implant-supported fixed dental prostheses (IFDPs) in partially edentulous patients with extended edentulous sites, ie, at least two adjacent teeth are missing. Only human studies with at least 10 cases and a minimum follow-up time of 12 months, reporting on solid-screw-type implants with rough surfaces and a diameter of at least 3 mm, were included. Weighted means of implant survival rates and risk ratios for implant survival at 1 year using meta-analytic tools were calculated to perform the following comparisons: IL vs EL, IL vs CL, and IL in the maxilla vs mandible. Noncomparative studies reporting on IL and EL protocols were summarized through descriptive methods. Results The search provided 3,872 titles, 837 abstracts, and 444 full-text articles. A total of 24 publications that comprised six comparative studies (five randomized controlled trials, one nonrandomized controlled trial) and 18 noncomparative studies were included for analysis. The comparison of weighted mean survival rates revealed no statistically significant difference between IL (97.9%) and EL (97.8%, P = .9405), and between IL (100%) and CL (99.3%, P = .3280). Meta-analysis showed no statistically significant difference in implant survival at 1 year between IL and EL (RR 0.90; 95% CI 0.30, 2.70; P = .502). A meta-analysis comparing IL and CL could not be performed due to the low number of failures. No statistically significant difference was found for IL implants placed in the maxilla vs the mandible (RR 1.55; 95% CI 0.49, 4.84; P > .05). Due to the small number of IL implants placed in the anterior, a comparison between implant survival in anterior vs posterior zones was not performed. Treatment modifiers were bone quality, primary stability, insertion torque, ISQ values, implant length, the need for substantial bone augmentation, the timing of implant placement, and the presence of parafunctional and smoking habits. Conclusions IL presents similar implant survival rates as EL or CL for partially edentulous patients with extended edentulous sites in the posterior zone, as long as strict inclusion/exclusion criteria are followed. There is a lack of evidence for IL of multiple implants in the anterior zone of partially edentulous patients. Preliminary evidence suggests that IL may be equally successful in either the maxilla or mandible. Further research is needed before IL in partially edentulous patients with extended edentulous sites can be recommended in everyday practice.

Implant loading protocols for partially edentulous patients with extended edentulous sites--a systematic review and meta-analysis

Recently, implant surgery has been introduced into postdoctoral prosthodontic programs; however, efficient training models to teach this have not been described to date For training models to be effective and acceptable to all parties, a mutually beneficial situation must be created, and guidelines that can be followed easily need to be described The purpose of this report is to suggest immediate loading of dental implants as an example for an interdisciplinary training model that integrates both the surgical aspects of implant therapy into the education of prosthodontic graduate students and the prosthodontic aspects of implant therapy into the training of periodontal graduate students A flow chart of training steps is described for a patient treated with an immediately loaded mandibular fixed full-arch prosthesis on five interforaminal implants Both the prosthodontic and the periodontal residents were involved in all phases of treatment These postdoctoral students were in the final year of their program Therefore, individual treatment steps could be taught interchangeably and accomplished by the student of the other specialty under the supervision of a clinical instructor The unique characteristic of the immediate loading procedure, which includes surgical implant placement as well as immediate conversion of an existing denture into a fixed implant-supported provisional prosthesis, allows each postgraduate student to experience detailed surgical and prosthodontic treatment in a controlled environment on the day of surgery

Alexander Schrott

Papers

Five-year evaluation of the influence of keratinized mucosa on peri-implant soft-tissue health and stability around implants supporting full-arch mandibular fixed prostheses.

Consensus statements and clinical recommendations for implant loading protocols.

Implant loading protocols for partially edentulous patients with extended edentulous sites--a systematic review and meta-analysis

Immediate loading as a vehicle for interdisciplinary training in implant placement and restoration.