Root submergence technique as a partial extraction therapy to preserve the alveolar ridge tissues: A systematic review and appraisal of the literature.

STATEMENT OF PROBLEM: As socket grafting with commercially available biomaterials has become popular, reports of the root submergence technique for ridge preservation have decreased. A systematic review of this partial extraction therapy is lacking. PURPOSE: The purpose of this systematic review was to review the root submergence technique as well as critically appraise the available data. MATERIAL AND METHODS: A review was carried out that observed the Participant, Intervention, Comparison, Outcomes (PICO) strategy and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The focused question was "What are the outcomes of the different methods to submerge tooth roots for ridge preservation?" Medical subject headings (MeSH) terms that related to the root submergence technique were searched in PubMed/MEDLINE, Scopus, and the Cochrane Library databases. RESULTS: A total of 7709 abstracts and study titles were individually screened from the initial search results. After reviewing the full-text articles and applying the selection criteria, the final included search results totaled 47 full-text articles for in-depth review. In 10 animal studies, 258 roots were studied in 34 dogs and 7 monkeys. Histological data confirmed that coronal bridging (bone or cementum growth over the cut root) was a common outcome. Of the vital roots submerged, the majority maintained their vitality. In 37 human studies, 475 roots were submerged and reported on. Subjective ridge preservation was often reported. Among the adverse healing outcomes, exposure of the root through the mucosa was the most common. Nonetheless, in animals, 86.8% of roots remained submerged; in humans, 74.7%. CONCLUSIONS: Root submergence is an established technique for ridge preservation. Exposure is a common complication, and correct technique may be key to its prevention. Further research of this partial extraction therapy is encouraged.

The root submergence technique at single tooth sites to short-span edentulous sites: A step-by-step partial extraction therapy protocol.

Submerging roots for ridge preservation was the earliest partial extraction therapy and has been described since the 1970s. Despite the approximately 47 animal and human studies published since, an updated and contemporary step-by-step protocol has not yet been provided. This technique report describes in detail how to manage submerged roots at single tooth sites and at short-span edentulous areas.

Comparison of excess cement around implant crown margins by using 3 extraoral cementation techniques.

STATEMENT OF PROBLEM: Extrusion of excess cement into the subgingival area around implant-supported crowns is associated with detrimental inflammatory response, but controlling this excess material remains a challenge. PURPOSE: The purpose of this in vitro study was to perform a comparative analysis of 3 extraoral cementation techniques to reduce excess extruded cementation material around implant-supported crowns. MATERIAL AND METHODS: Forty-four internal connection implant replicas were embedded in acrylic resin to form the experimental model. Cementable abutments were tightened onto the implants. Zirconia crowns were luted to each of the cementable abutments by using 1 of 4 techniques: control, pattern resin analog that was 3D-printed, fast-setting polyvinyl siloxane analog, and putty index analog. Extruded excess cement was collected at each luted crown and weighed. RESULTS: The mean residual weight of excess cement found in the pattern resin analog technique group was the least (0.087 mg), followed by the polyvinyl siloxane analog technique group (1.678 mg). The putty index analog technique group reported the least reduction of excess extruded cement (7.621 mg). All techniques produced substantially less extruded cement than the control (85.166 mg). In a 1-way analysis of variance, statistically significant differences (P<.001) were found among all the test techniques. Pairwise comparisons also found that all 3 test techniques were statistically different from each other. CONCLUSIONS: The pattern resin (3D-printed) analog technique produces the least amount of extruded excess cement at an implant-supported crown, limiting detrimental impact on peri-implant tissue health.

Esthetic tunnel exposure: A combination technique for peri-implant soft tissue development at second-stage surgery.

An esthetically pleasing result is the product of both prosthetic excellence and the health and quality of the soft tissue that frames the restoration. Management of the peri-implant coronal soft tissue is key to the ultimate success of treatment. This technique report describes an alternative, novel approach, combining established concepts and methods into a single technique to improve esthetic results.

Prosthetic management of implants placed with the socket-shield technique.

Partial extraction therapies, such as the socket-shield technique, use the patient's tooth tissues and periodontium to preserve the alveolar ridge and limit postextraction resorption. Internal exposure through the overlying peri-implant mucosa has been reported as the most common complication, suggesting that the preparation technique requires modification. This technique report describes the prosthetic management of the socket-shield technique, emphasizing preparation of the socket-shield to the bone crest, and the creation of an S-shape prosthetic emergence profile to support maximal soft tissue infill.

The socket-shield technique at molar sites: A proof-of-principle technique report.

The socket-shield technique for avoiding postextraction tissue alteration was first described in 2010. The technique was developed for hopeless teeth in anterior esthetic sites but has not yet been described for molar sites. Managing postextractive ridge changes in the posterior region by prevention or regeneration remains a challenge. The socket shield aims to offset these ridge changes wherever possible, preserving the patient's residual tissues at immediate implants. This technique report describes the molar socket-shield step by step.

Radial plane tooth position and bone wall dimensions in the anterior maxilla: A CBCT classification for immediate implant placement.

STATEMENT OF PROBLEM: The biological and esthetic challenge of the post-extraction ridge is relevant to restorative implant dentistry, most significantly in the anterior esthetic zone. Previous authors have discussed facial bone wall dimensions and classified their variations. A reclassification may be pertinent. PURPOSE: The purpose of this observational, clinical study was to introduce a new classification system for anterior maxilla tooth position with guidelines for immediate implant placement. Data for facial and palatal bone wall height and thickness are also presented. MATERIAL AND METHODS: Maxillary anterior teeth (n=591) were analyzed as viewed in the radial plane of cone beam computed tomography (CBCT) scans from 150 patients. Each tooth was classified according to its position and inclination within its alveolus (class I, middle of the alveolus; IA, thick facial bone; IB, thin facial bone; class II, retroclined; IIA, thick crestal bone; IIB, thin crestal bone; class III, proclined; class IV, facially outside bone envelope; class V, both thin facial and palatal bone with apical isthmus). Bone thickness was measured for both facial and palatal walls at the following points: crestal (A), mid-root (B), apex (C), and 4 mm beyond the apex. Bone wall height was also evaluated. RESULTS: A thin facial bone wall predominated (≤1 mm) at the crest (83%) and the mid-root point (92%). Most palatal walls were thin (<1 mm) at the crest (63%) and thick (≥2 mm) at the mid-root point (98%) and apex (99%). Class I tooth position accounted for 6.1%, class II for 76.5%, class III for 9.5%, class IV for 7.3%, and class V for 0.7%. CONCLUSIONS: Maxillary anterior teeth have predominantly thin facial bones, making palatal bone thickness a crucial variable. The new classification system for radial plane tooth position is a pragmatic clinical analysis for immediate implant treatment planning.

Rationale for vertical periodontal defects being a contraindication to the socket-shield technique.

Much has been published on the socket-shield technique since its introduction to implant dentistry in 2010. The literature reports the technique to be a viable treatment option. Investigations should hence focus on improving the treatment, identifying pitfalls, and better educating clinicians. The technique has been advised as contraindicated at tooth roots with periodontal defects. The present case report aims to illustrate the additional risk and why intrabony periodontal defects may be a contraindication to this already challenging treatment.

Dimensions of the dentogingival tissue in the anterior maxilla. A CBCT descriptive cross-sectional study.

BACKGROUND: The characteristics of the periodontium in anterior teeth influence the outcomes and prognosis of different periodontal, implant, and restorative procedures. In the present study, CBCT images were used to determine alveolar bone thickness and, to a lesser extent, gingival thickness. The aim was to evaluate the use of CBCT to measure the dentogingival complex in the anterior maxilla. MATERIALS AND METHODS: CBCT scans from 25 healthy patients were taken and the maxillary anterior teeth (n = 138) analyzed in the radial plane. The study provided descriptive data on gingival thickness, alveolar bone thickness (horizontal measurements), and vertical measurements related to biologic width. RESULTS: The mean distance from gingival margin to bone crest (BC) was 3.4 ± 0.7 mm, and that between the cementoenamel junction and BC was 2.6 ± 1.0 mm. The average mid-labial gingival thickness 1 mm apical of the gingival margin was 1.0 ± 0.3 mm; a thinner gingiva was observed in females (P = 0.01) and canines (P < 0.001). The average crestal labial bone thickness was 0.8 ± 0.3 mm. In total, 62% of the tooth sites had a thin gingiva (< 1 mm), and 72% had thin labial bone plates; a moderate positive correlation was found between these parameters (P < 0.001). CONCLUSIONS: CBCT was effective in providing data on the thickness of the labial plate and gingiva as well as on the relationship among BC, CEJ, and gingival margin. The majority of tooth sites had thin labial bone and thin gingiva, with thinner gingiva observed in females and at canine sites.

A decade of the socket-shield technique: a step-by-step partial extraction therapy protocol.

Ten years have passed since Hürzeler and coworkers first introduced the socket-shield technique. Much has developed and evolved with regard to partial extraction therapy, a collective concept of utilizing the patient's own tooth root to preserve the periodontium and peri-implant tissue. The specifications, steps, instrumentation, and procedures discussed in this article are the result of extensive experience in refining the socket-shield technique as we know it today. A repeatable, predictable protocol is requisite to providing tooth replacement in esthetic dentistry. Moreover, a standardized protocol provides a better framework for clinicians to report data relating to the technique with procedural consistency. This article aims to illustrate a reproducible, step-by-step protocol for the socket-shield technique at immediate implant placement and provisionalization for single-rooted teeth.

Hyperplastic Response Following Soft Tissue Augmentation in the Esthetic Zone.

INTRODUCTION: The indications for augmentation of gingival tissue by connective tissue graft (CTG) are numerous. The techniques are widely adopted with extensive literature reporting high success. Harvest techniques include the mid to anterior palate, versus the posterior palate and tuberosity. The latter comprises denser collagen, identified as a more suitable graft. Alas, rarely have hyperplastic responses been reported. CASE PRESENTATION: Two adult, Caucasian patients presented with clinical need for soft tissue augmentation. Autogenous tissue was opted for, harvesting from the tuberosity gingiva. De-epithelialized outside the mouth and inserted into envelope flaps, late healing resulted in hyperplastic gingival lesions. Neither lesion could be successfully removed, and biopsy for histopathological investigation was carried out. CONCLUSION: Hyperplastic response resulting from soft tissue augmentation with tuberosity CTG is rare but may occur. Laser or scalpel might not ensure complete removal. Informing the patient of this rare adverse effect may be important.

A retrospective evaluation of 128 socket-shield cases in the esthetic zone and posterior sites: Partial extraction therapy with up to 4 years follow-up.

OBJECTIVES: Tooth loss results in an inevitable alveolar ridge reduction. This has established a cautionary approach to extract, wait, augment, and insert the implant, in lieu of immediate placement. However, saving the tooth or part of it whenever possible is more conservative and supports the vital periodontal tissue buccofacial to an implant. The purpose of this cases series was to report on implant survival using this technique in a large cohort of patients at mid-term follow-up. MATERIALS AND METHODS: A private practice patient database was searched for all patients having received socket-shield treatment in conjunction with immediate implant placement. Of the results returned, 128 met the inclusion criteria of ≥12 months from date of restoration, or failing prior to definitive restoration. These patients were recalled for evaluation of the restored implants up to 4 years post-treatment. RESULTS: Seventy immediate implants with socket-shields were placed in female patients and 58 in males, age range 24-71 (mean 39 years). The distribution of sites treated were: maxillary incisors (64%), premolars (22%), canines (14%); maxilla (89.9%), mandible (10.1%). 123/128 implants osseointegrated and survived 1-4 years following restoration (survival rate 96.1%). A combined complication rate of 25/128 implants occurred (19.5%). Five implants failed to osseointegrate and were removed. The remaining 20 complications were all managed or observed without management, with implants surviving at mid-term follow-up. CONCLUSIONS: Notwithstanding technique sensitivity and the need for randomized control studies, this case series demonstrates that the socket-shield performs competitively when compared to implant survival rates in both conventional immediate and delayed implant placement.

Human Histologic Evidence of New Bone Formation and Osseointegration Between Root Dentin (Unplanned Socket-Shield) and Dental Implant: Case Report.

The socket-shield technique described 7 years ago has since grown in its reporting in the literature as a valid method of ridge preservation at immediate implant placement. To date, large clinical cohorts with up-to-4-year follow-up have been reported. Additionally, evidence of tissue histology at the dental implant and socket-shield has been demonstrated in the animal model. However, human histologic evidence has not yet been available, and the clinician's uncertainty regarding the tissues that may form between the socket-shield and dental implant may remain unanswered until now. This case report presents the first human histologic evidence that bone may entirely fill the space between root dentin and an osseointegrated implant surface.

Partial Extraction Therapies (PET) Part 2: Procedures and Technical Aspects.

Part 1 of this series introduced the partial extraction therapies as a group of techniques for ridge preservation at immediate implant placement and beneath pontic sites. The concept proposes a paradigm shift away from extract and augment toward partly retaining the tooth root to preserve the ridge and prevent buccopalatal collapse. The revolutionary socket-shield technique was introduced in 2010; however, there has been no follow-up literature to guide the clinician in terms of procedural steps. While root submergence is well established, the socket-shield and pontic shield are still in their clinical infancy and require long-term clinical data before they can be proposed as routine in everyday implant dentistry. Yet without sound knowledge on how to carry out the partial extraction therapies, a global dental community cannot participate in their application or contribute to the growing knowledge base. In this, the second part of the series, the procedures for root submergence, socket-shield, and pontic shield are addressed, step by step, supplemented with applicable guidelines as the first such publication guiding the clinician to apply these root- and ridge-preservation techniques. Technical aspects and complication management are also addressed.

The Palatal Bone Block Graft for Onlay Grafting Combined with Maxillary Implant Placement: A Case Series.

The aim of this study was to introduce an intraoral bone block harvesting technique--the palatal bone block graft (PBBG)--as an alternative harvest site for autogenous bone blocks. The PBBG technique was used to onlay graft esthetic zone defects simultaneous to implant placement in five patients. Measurable objectives were used to evaluate outcomes, and treatment was reassessed at up to 6 years. Defects of the maxilla were successfully grafted with PBBG in all five cases, and tissues remained stable at 1- and 6-year follow-ups. Harvesting an autogenous bone block from the palate is an advantageous, predictable, and reproducible method for augmenting buccofacial defects at implant placement, and may be considered as an alternative to conventional intraoral bone block donor sites when treating the maxilla.

Choukroun Platelet-Rich Fibrin as an Autogenous Graft Biomaterial in Preimplant Surgery: Results of a Preliminary Randomized, Human Histomorphometric, Split-Mouth Study.

This study aimed to test the null hypothesis that platelet-rich fibrin (PRF), as an immediate postextraction graft material, produces bone that is histomorphometrically no different than bone derived from healing without intervention. The authors compared split-mouth human bone biopsy specimens derived from PRF with bone that had healed without intervention. Eight human bone biopsies were successfully harvested from four patients. The mean ± standard deviation (SD) percent of newly formed osteoid was 9.9% ± 5.9% for specimens derived from PRF, and 4% ± 2.1% for specimens derived from the control sites (P = .089; 95% confidence interval [CI] 4.5-18.1 and 1.6-6.6, respectively). Mean ± SD percent of new mineralized bone was 40.8% ± 10.3% for the PRF specimens and 43.9% ± 16.8% for the control specimens (P = .72, 95% CI, 33.4-55.6 and 19.3-55.5, respectively). Newly formed bone to fibrovascular tissue ratios for specimens in the PRF and control groups were 51%:49% and 48%:52%, respectively. Within the limitations of this study, the null hypothesis could not be rejected. Bone derived from PRF histologically did not differ from bone that healed without intervention.

The Pontic-Shield: Partial Extraction Therapy for Ridge Preservation and Pontic Site Development.

Augmentive ridge preservation techniques aim to manage the postextraction ridge. The partial extraction of teeth may better preserve the ridge form by maintaining the bundle bone-periodontal ligament apparatus. Root submergence has been demonstrated to retain the periodontal tissues and preserve the ridge beneath dentures or fixed prostheses. The socket-shield technique entails preparing a tooth root section simultaneous to immediate implant placement and has demonstrated histologic and clinical results contributory to esthetic implant treatment. A retrospective 10-patient case series treating 14 partial extraction sites demonstrates how a modification of the socket-shield technique can successfully develop pontic sites and preserve the ridge.

Partial Extraction Therapies (PET) Part 1: Maintaining Alveolar Ridge Contour at Pontic and Immediate Implant Sites.

Buccopalatal collapse of the postextraction ridge is a significant challenge in restorative and implant dentistry. A variety of ridge preservation techniques using tissue and augmentative materials have been proposed in the literature. A slightly different approach is to use the tooth itself. Root submergence has been reported in the literature for more than 4 decades, and it has been demonstrated that the submerged tooth root retains the periodontal tissues and preserves the bone in pontic sites or below dentures to retain the ridge. The socket-shield technique entails preparing a tooth root section simultaneous to immediate implant placement and has demonstrated histologic and clinical results that are highly promising to esthetic implant treatment. The pontic shield technique preserves the alveolar ridge at sites intended for pontic development where the root submergence technique is not possible. The aforementioned techniques collectively may be termed partial extraction therapies (PET), a term newly introduced into the literature and clinical environment. This article is a review of these ridge preservation therapies, providing a classification and a guide to their application.

Implant Injury Case Series and Review of the Literature Part 1: Inferior Alveolar Nerve Injury.

Injury to adjacent structures is an unfortunate and avoidable outcome of oral implant placement surgery. Paramount among these is perforation into paranasal sinus; into neighboring tooth root; through cortical plate; and into vessels, canals, and, most importantly, nerves. In most cases, injudicious oral implant placement can be attributed to poor treatment planning. We present the cases of several patients referred for postsurgical radiology that illustrate injury to the inferior alveolar canal by implant impingement, penetration, and even complete obliteration of the nerve and canal in the absence of proper treatment planning and imaging modalities. The authors stress the importance of thorough implant case preparation and planning, which may include the use of cone beam computerized tomography in order to minimize nerve injury.