Baltic Ossoeintegration Academy (BOA) together with the Lithuanian University of Health Sciences (LSMU) and Universities from Europe and USA organized their second Consensus Conference (CC) devoted to the topic of "Post-Extraction Bone Remodelling and Alveolar Ridge Preservation". BOA - LSMU consensus development group (CDG) was seeking to review the dental literature on a topical area in dental implantology and to produce high-quality, unbiased evidence-based guidelines and consensus statement (CS). CDG as the responsible body formulated the task of developing CS devoted to the topic of "Post-Extraction Bone Remodelling and Alveolar Ridge Preservation" to Gintaras Juodzbalys (Lithuania). CS Panel members were invited by the chairman. They are representatives of Universities, experts in a field and made every effort to produce nonbiased, independent, evidence-based clinical practice guidelines. Panel members had no conflicts of interest and signed a Panel Member Agreement (PMA). Working groups were established and following clinically relevant topics suitable for consensus discussion were identified:

1. Biological aspects of tooth extraction, socket healing and indications for socket preservation (group leader: Gintaras Juodzbalys) [1].
2. Extraction socket preservation methods and dental implant placement outcomes within grafted sockets (group leader: Pablo Galindo-Moreno) [2].

Objectives: The present manuscript aims to critically detail the physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates, addressing the associated molecular and cellular events that culminate in the restoration of the lost tissue architecture and functionality.

Material and Methods: An electronic search in the National Library of Medicine database MEDLINE through its online site PubMed and Web of Science from inception until May 2019 was conducted to identify articles concerning physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates. The search was restricted to English language articles without time restriction. Additionally, a hand search was carried out in oral surgery, periodontology and dental implants related journals.

Results: In total, 122 literature sources were obtained and reviewed. The detailed biological events, at the molecular and cellular level, that occur in the alveolus after tooth extraction and socket healing process modulated by grafting materials or autologous platelet concentrates were presented as two entities.

Conclusions: Tooth extraction initiates a convoluted set of orderly biological events in the alveolus, aiming wound closure and socket healing. The healing process comprises a wide range of events, regulated by the interplay of cytokines, chemokines and growth factors that determine cellular recruitment, proliferation and differentiation in the healing milieu, in a space- and time-dependent choreographic interplay. Additionally, the healing process may further be modulated by the implantation of grafting materials or autologous platelet concentrates within the tooth socket, aiming to enhance the regenerative outcome.

Objectives: The aim of present study was to review current literature concerning extraction socket classification immediately following tooth extraction and the rationales for socket preservation/augmentation procedures and with reference to it suggest novel clinical decision tree for extraction socket preservation/augmentation in aesthetic and non-aesthetic area.

Material and Methods: The search protocol used the electronic MEDLINE (PubMed) and EMBASE databases for articles published between January 1 2009 and May 1 2019. The search included only human studies published in English. Outcomes were the indications and reasons for socket preservation/augmentation and classification of extraction sockets.

Results: Ten studies fulfilled the inclusion criteria and were selected for the study. Although there are various types of extraction socket classifications none of them could completely evaluate all morphological parameters of alveolar ridge. Furthermore, present study revealed that indications for extraction socket preservation/augmentation have wider spectrum than socket morphology and are related to surrounding tissue anatomy or dental implantation operation indications and timing. Based on currently proposed extraction socket classifications and rationales, a novel decision tree for extraction socket preservation/augmentation immediately after tooth extraction in aesthetic and non-aesthetic area was suggested.

Conclusions: The need of extraction socket preservation/augmentation immediately after tooth extraction should be determined by the aesthetic, functional and risk-related viewpoint. A novel clinical decision tree for extraction socket preservation/augmentation immediately after tooth extraction in aesthetic and non-aesthetic zones can be useful tool in socket preservation/augmentation procedures.

Introduction: The task of Group I was to review and update the existing data concerning the physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates, addressing the associated molecular and cellular events that culminate in the restoration of the lost tissue architecture and functionality. The second task was to review current literature concerning extraction socket classification immediately following tooth extraction and the rationales for socket preservation/augmentation procedures and with reference to it suggest novel clinical decision tree for extraction socket preservation/augmentation in aesthetic and non-aesthetic area.

Material and Methods: The main areas indicated by this group were as follows: socket healing process, including haemostasis and coagulation, inflammatory phase, proliferative phase, bone tissue modelling and remodelling; socket healing with graft materials and autologous platelet concentrates; extraction socket classifications; indications and reasons for extraction socket preservation/augmentation. The systematic reviews and/or meta-analyses were registered in PROSPERO, an international prospective register of systematic reviews: http://www.crd.york.ac.uk/PROSPERO/. The literature in the corresponding areas of interest was screened and reported following the PRISMA (Preferred Reporting Item for Systematic Review and Meta-Analysis) Statement: http://www.prisma-statement.org/. Method of preparation of the systematic reviews, based on comprehensive search strategies, was discussed and standardized. The summary of the materials and methods employed by the authors in preparing the systematic reviews and/or meta-analyses is presented in Preface chapter.

Results: The results and conclusions of the review process are presented in the respective papers. One theoretical review-analysis and one systematic review were performed. The group's general commentaries, consensus statements, clinical recommendations and implications for research are presented in this article.

Objectives: The purpose of this systematic review was to assess quantitatively and qualitatively the influence of two different factors: membranes and soft tissue graft influence for the extraction socket preservation.

Material and Methods: A wide-ranging electronic search was performed in six databases up to 30 of November 2018 in order to identify all the clinical and randomized clinical trials performed in humans published with no data restriction. The inclusion criteria were extraction socket preservation with and without membranes or a soft tissue graft in a intact socket with at least six months of follow-up, have more than 12 patients or treat more than 12 sites per group and evaluated at least one of the primary outcomes measures (radiographic measures histological assessment, clinical measures).

Results: From an initial search of 1524 studies only 6 papers fulfil the inclusion and exclusion criterions. All the six selected papers, presented a wide heterogeneity of treatments used, evaluated variables and observation period that made impossible to recommend any specific techniques and/or material to achieve better results. The limited data found suggest that the used of membrane reveals to achieve better results. It wasn’t possible to observe in any clinical trial that compares the used of soft tissue graft.

Conclusions: New trials need to be performed in order to identify what specific techniques and/or materials are better to decrease the reabsorption of the socket after tooth extraction. Clinical trials designed to understand when/how the soft tissues grafts influence at the socket preservation is needed.

Objectives: The purpose of the present review was to evaluate the effect of different bone substitutes used for alveolar ridge preservation on the post extraction dimensional changes.

Material and Methods: An electronic literature search in MEDLINE (PubMed), EMBASE (OVID) and Cochrane (CENTRAL) were performed, in addition to a manual search through all periodontics and implantology-related journals, up to December 2018. Inverse variance weighted means were calculated for all the treatment arms of the included trials for the quantitative analysis

Results: Forty randomized controlled trials were included in the quantitative analysis. The average amount of horizontal ridge resorption was 1.52 (SD 1.29) mm (allograft), 1.47 (SD 0.92) mm (xenograft), 2.31 (SD 1.19) mm (alloplast) and 3.1 (SD 1.07) mm for unassisted healing. Similarly, for all the evaluated parameters, the spontaneous healing of the socket led to higher bone loss rate than the use of a bone grafting material.

Conclusions: The utilization of a bone grafting material for alveolar ridge preservation reduces the resorption process occurring after tooth extraction. However, minimal differences in resorption rate were observed between allogeneic, xenogeneic and alloplastic grafting materials.

Objectives:: To evaluate the reported literature on the use of stem cells or growth factors for post extraction treatment of the alveolar bone.

Material and Methods: A NCBI PubMed and PubMed Central databases search was conducted between September 2010 and August 2018, to identify animal or clinical studies reporting the clinical, radiographical and/or histological outcomes of socket preservation techniques after applying mesenchymal stem cells or growth factors. Only studies published in English language in the last 10 years were included in the study

Results: Eleven studies were identified fulfilling the inclusion criteria. They evaluate a total of 386 post extraction sockets. The main tested materials identified in the current review were bone morphogenetic protein-2 - 3 studies and mesenchymal stem cells - 3 studies. Other comparators were bone morphogenetic protein-9, platelet-derived growth factor-BB homodimers and bone marrow. Overall evaluation indicate positive results for all test groups showing differences in final socket width between 0.64 and 1.28 mm favouring the test groups. Histologically, no particular differences are detected between test and control groups. Most of the studies present low risk of bias.

Conclusions: In general, the use of mesenchymal stem cells or bioactive osteogenic molecules favours bone regeneration after tooth extraction, as evaluated clinically, radiographically and histologically. However, specific differences that support particular recommendations are still unclear in light of the current published evidence. Future studies should include the standardization of the mesenchymal stem cells selection and purification as well as dosage and delivery methods of bioactive molecules.

Objectives: To assess the treatment outcomes of the dental implants placed in the grafted sockets.

Material and Methods: A search protocol was developed to evaluate the treatment outcomes of dental implants placed in the grafted sockets in terms of implant survival rates (primary outcome), marginal-bone-level (MBL) changes, clinical parameters (i.e., bleeding on probing, probing depth), occurrence of peri-implant diseases, and aesthetic outcomes (secondary outcomes). Randomized controlled clinical trials (RCTs), controlled clinical trials, and prospective studies with at least 12 months of follow-up and a minimum of 10 patients having at least one dental implant inserted into the grafted socket were conducted. MEDLINE (PubMed) was searched for relevant articles published until 1^st April 2019. A meta-analysis was performed using the random-effects model on the selected qualifying articles.

Results: The present analysis included 7 RCTs. The survival rate of the implants inserted into the grafted sockets ranged from 95 to 100% after 1 to 4 years of follow-up. MBL loss was found to be significantly greater for the implants placed in the non-grafted healed sites than for those placed in the previously grafted sockets (weighted mean difference = -1.961 mm, P < 0.0001). In terms of MBL changes, no difference was detected between immediately inserted implants versus implants placed in previously grafted sockets. None of the included studies reported on the clinical parameters or occurrence of peri-implant diseases.

Conclusions: Implants inserted into the previously grafted sockets showed high survival rates and lower marginal-bone-level loss than the implants inserted into the non-grafted sites.

Introduction: The task of Group II was to review and update the existing data concerning extraction socket preservation with or without membranes and soft tissue influence on post-extraction alveolar ridge preservation; extraction socket preservation using different biomaterials as bone grafts, growth factors, and stem cells. Special interest was paid to the dental implant placement outcomes within grafted sockets.

Material and Methods: The main areas evaluated by this group were as follows: quantitative and qualitative assessment of the effect of different alveolar preservation techniques performed immediately after tooth extraction, with or without membranes and/or soft tissue grafting, and the use of different bone substitutes, stem cells or growth factors in the postextraction socket. Evaluation of the treatment outcomes of dental implants placed in the grafted sockets in terms of primary and secondary outcomes were assessed. The systematic reviews and/or meta-analyses were registered in PROSPERO, an international prospective register of systematic reviews: http://www.crd.york.ac.uk/PROSPERO/. TThe literature in the corresponding areas of interest was screened and reported following the PRISMA guidelines (Preferred Reporting Item for Systematic Review and Meta-Analysis) Statement: http://www.prisma-statement.org/. Method of preparation of the systematic reviews, based on comprehensive search strategies, was discussed and standardized. The summary of the materials and methods employed by the authors in preparing the systematic reviews and/or meta-analyses is presented in the Preface chapter.

Results: The results and conclusions of the review process are presented in the respective papers. Three systematic reviews and one systematic review and meta-analysis were performed. The group's general commentaries, consensus statements, clinical recommendations and implications for research are presented in this article.