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

Comparative Effectiveness of an Autologous Dentin Matrix for Alveolar Ridge Preservation

An urgent issue is the preservation or reconstruction of the volume of bone tissue in planning and surgical treatment in the fields of medicine, such as traumatology, orthopedics, maxillofacial surgery and dentistry. After tooth extraction, resorption of the bone tissue of the alveolar crest of the jaws occurs, which must either be further eliminated by performing additional operations or using osteoplastic material for socket preservation at the extraction stage. Background and Objectives: The aim of the study was a comparative analysis of various osteoplastic materials used to preserve the volume of bone tissue in the preimplantation period. Materials and Methods: As part of the study, 80 patients were treated, who underwent socket preservation using xenografts, plasma enriched with growth factors, an autologous dentin matrix (ADM) and hydroxyapatite. Results: The results of the treatment 16 weeks after removal were comprehensively analyzed using a morphometric analysis of the bone's volume, cone beam tomography and morphological examination of burr biopsy specimens, as well as by determining the stability of the installed implant at different stages of treatment. Conclusions: The lowest level of bone tissue resorption according to the CBCT data was noted in the ADM and xenograft groups. It should be noted that the use of osteoplastic material in jaw surgery when reconstructing alveolar defects is an essential procedure for preventing the atrophy of bone tissue.

Comparative evaluation of conventional and socket-shield techniques on maxillary esthetics following immediate implant placement in fresh extraction sockets: A randomized controlled trial

Background

Dental implants in fresh extraction sockets of the maxillary esthetic area are technique-sensitive procedures where retaining a buccal root segment can enhance periodontium preservation and esthetics. This study aims to compare marginal bone levels and esthetic outcomes between conventional immediate implant placement and the socket-shield technique in fresh maxillary extraction sockets.

Materials and Methods

Twenty-four patients with type 1 extraction sockets were included in this randomized trial and assigned to either conventional immediate implant placement or the socket-shield technique. Implant survival, crestal bone levels, and pink esthetic scores (PES) were evaluated at 8 months (temporary prosthesis), 12 months, and 36 months (final crowns).

Results

All implant-supported restorations were successful within the study's observation period. The socket-shield technique showed significantly lower marginal bone loss (e.g. 1.40 ± 0.29 mm vs. 1.70 ± 0.36 mm at 36 months; P = 0.040) and superior PES (e.g., 10.50 ± 0.90 vs. 9.36 ± 0.98 at 36 months; P = 0.008) compared to the conventional technique. However, the technique's complexity underscores the need for expertise and careful execution to optimize tissue preservation in the maxillary esthetic zone.

Conclusion

The socket-shield technique better preserves hard and soft tissues around implant-retained prostheses than conventional implant placement in maxillary esthetic regions. Further studies with larger sample sizes and longer follow-up are required to validate these findings.

Finite element analysis of stress distribution on residual root structure in socket shield procedure following immediate dental implant placement: an in vitro study

BACKGROUND

The success of implants in the socket shield technique relies on stress experienced by root fragments within the socket. Although there is no consensus on optimal root fragment thickness, varying thicknesses and dynamic implant placement induce stress in various directions and degrees. This study aimed to assess biomechanical response and stress distribution across different root fragment thicknesses in the socket shield procedure.

METHODS

This in vitro study was conducted to assess and compare the stress distribution on residual root structures of varying thicknesses positioned within the labial aspect of the maxillary incisor socket during immediate implant placement of standard dimensions. The procedure involved applying an insertional torque of 40 Ncm, and the analysis was conducted using finite element analysis software.

RESULTS

Utilizing the Numerical Technique with Abaqus software for explicit dynamics, von Mises stress and principal strain were analyzed on the root structure and bone under nonlinear contact conditions during implant torque application. For Model A, a loading torque of 40 Ncm was applied vertically on the implant, along with a horizontal force of 20 N on the root structure and bone. Results indicated maximum stress of 12.68 MPa on the root structure with a thickness of 0.5 mm and 5.61 MPa on the bone, with principal strains of 6.82E-03 and 4.10E-03, respectively. In Model B, with a root structure thickness of 1.0 mm, the maximum stress increased to 19.70 MPa, while the bone stress rose to 9.51 MPa, with principal strains of 1.03E-02 and 6.09E-03. Model C, with a root structure thickness of 1.5 mm, exhibited a maximum stress of 21.58 MPa on the root and 10.12 MPa on the bone, with principal strains of 1.16E-02 and 6.10E-03. Lastly, in Model D, with a root structure thickness of 2.0 mm, the maximum stress on the root structure and bone escalated to 28.74 MPa and 11.38 MPa, respectively, with principal strains of 1.55E-02 and 8.31E-03.

CONCLUSIONS

As the thickness of the shield increases (ranging from 0.5 to 2 mm) in socket shield procedures with immediate implant placement, both stress on the root fragment and bone and principal micro-strain escalate. However, employing a shield thickness within the range of 0.5 to 2 mm does not lead to any adverse stress generation on the residual root fragment. However, for enhanced safety, it is recommended to restrict the maximum diameter and extension of the root fragment to 1.5 mm when considering implant sizes and socket diameter for the socket shield technique.

Dual-guide template-guided socket-shield preparation and immediate implantation in maxillary anterior region implant surgery

For immediate implants in the anterior region, the socket-shield technique has received much attention in recent years. However, this technique is technically sensitive and root preparation is difficult. It is also difficult to obtain the ideal three-dimensional position for implant placement in the anterior region. This paper reports a clinical case in which socket-shield preparation and implant cavity preparation were performed with the aid of a dual guide in implant surgery. The dual guide surgical preparation technique was used to reduce the difficulty of socket-shield preparation and to achieve restoration-orientated implant placement with satisfactory clinical results.

Peri-implant cell differentiation in delayed and immediately-loaded dental implant: A mechanobiological simulation

OBJECTIVE

This study aimed to investigate the effect of immediate versus delayed dental implant placement strategies on cell differentiation in a dental callus.

DESIGN

The implant was placed in the mandible with two nearby teeth using an idealized two-dimensional finite element model. Eight weeks after surgery, the mechanobiological modeling of healing was used to estimate cell differentiation. It was assumed that the callus was initially filled by mesenchymal cells. The model then transformed mechanical stimuli received by the callus from loadings in terms of distortional and dilatational strains into predictions of the cellular phenotypes, including fibroblasts, chondrocytes, and osteoblasts, or whether they would remain unchanged or die.

RESULTS

The results demonstrated that delayed loading led to greater bone formation than immediate loading. Osteoblast colonies were observed in the base of threads in the immediately-loaded implant, whereas the delayed loading caused distant bone formation from the surrounding bone side towards the implant. The osteoblasts were differentiated from both intramembranous and endochondral mechanisms of ossification. After eight weeks, approximately 61 % of the callus was ossified in the delayed placement model compared to 35 % in the immediate placement model, resulting in a greater amount of fibrocartilaginous tissue on the bone side of the callus.

CONCLUSIONS

Immediate and delayed loading models generated different results. In the delayed strategy, bone cells were supplied appropriately during the first few weeks following surgery, whereas the immediate loading caused fibrocartilaginous tissue differentiation. In the form of distant osseointegration, the secondary stability of the dental implant was higher and faster due to the delayed placement.

Comparing Dual-Zone Immediate Implant Placement and Socket Shield Technique for Ridge Width Changes in the Maxilla: A Prospective Cohort Study

PURPOSE

The aim of this prospective cohort study was to assess the facial-palatal ridge dimensional changes that occurred at 8-10 months following flapless dual-zone (DZ) immediate implant placement and socket-shield (SS) immediate placement in the maxilla.

MATERIALS AND METHODS

A total of 19 patients who received 20 implants were included, with 10 implants (MegaGen AnyRidge) placed for each treatment, DZ and SS. Cast models were made at 8-10 months after implant placement to assess the dimensional ridge changes by measuring the facial-palatal ridge width on implant sites (T) at six designated points starting from the gingival margin (0, 1, 2, 3, 5 and 7) and comparing it with the corresponding measurement on the contralateral tooth site (C).

RESULTS

All 20 implants demonstrated successful osseointegration at 8-10 months follow-up (survival rate 100%). Two out of ten cases of SS group presented with minor manageable complications of external shield exposure. DZ group showed an average of 0.3 mm facial-palatal ridge width reduction, while SS group revealed a mean gain in ridge width of approximately 0.2 mm at 8-10 months follow-up.

CONCLUSION

When comparing between two treatments, there was a significant difference in ridge width change at 8-10 months following implant placement, indicating better preservation of the ridge contour for socket shield technique.

Partial Extraction Therapy with Early Implant Placement in the Esthetic Zone: A Clinical Case Report

Immediate replacement of teeth designated for extraction is an appealing treatment rationale for both the patient and the operator. However, it has been associated with a greater risk of facial recession and compromised soft-tissue esthetics. Partial extraction therapy (PET) or synonymously socket shield technique (SST) or root membrane technique (RMT) has been proposed to conserve the facial alveolar contour and soft-tissue esthetics. In this article, a special case is described where a root membrane was used to prevent the modeling of the facial aspect of the extraction socket. Partial extraction was performed allowing the socket with the facial root membrane in situ to partially heal for 8 weeks before implant placement. Successful integration and restoration were achieved with very minimal hard- and soft-tissue changes, accentuating satisfactory esthetic results as dictated by objective esthetic assessment. PET with early implant placement may be considered a viable treatment option for selected cases.

Is socket shielding an option in esthetic region?

The implant cannot preserve the surrounding bone from resorption when placed in the extraction socket. After teeth extraction, a change in the bony architecture of the anterior region makes oral rehabilitation difficult by an implant. This leads us to explore such a critical issue and the relevant data were collected from Pubmed, Google Scholar, and Cochrane database and reviewed. Socket shielding technique is intentional retention of the buccal segment of root fragment during the implant placement in the extraction socket. Socket shielding is an effective procedure in minimizing the buccal bone resorption along with minimizing the buccal contour changes it is minimally invasive as the bone graft is optional thus reducing the cost of the treatment procedure. The limited studies were available to support the routine clinical use of the socket shielding technique. Socket shielding seems to become the non-invasive technique for the preservation of hard and soft tissue by dental implant especially in the esthetic zone in the future. Therefore studies should be carried out on a large population to obtained more précised results related to the socket shielding technique.

Socket shield technique and delayed implant placement in maxilla: a series of five case reports

Background

Tooth extraction is often followed by remodeling of hard and soft tissues, while socket shield technique has been proposed to prevent or minimize this remodeling. Socket shield accompanied with delayed implant placement is a novel technique that could be used when delayed implantation is selected; however, more scientific based evidence is required to recommend this technique as everyday clinical practice. Thus, the aim of this case series was to assess the clinical, radiographic, and esthetic outcomes of the delayed placed implants associated with previously prepared socket shield at 3–15 months follow-up after loading. The stability of the shield and the depth of soft tissue penetration palatal to the shield at reentry of 3–6 months were also assessed.

Cases presentation

Five case reports of socket shield with delayed implant placement were described in the study. The facial shields were prepared and simultaneously the sockets were grafted with mineralized allograft particles, then the implants were placed 3–6 months later. Periodontal probe was used to measure the depth of soft tissue penetration palatal to the shield at reentry. Clinical indices of bleeding index, plaque index, and probing depths were recorded. Radiographic evaluation to record the amount of marginal bone loss post-loading, esthetic assessment using modified pink esthetic score, and patient assessed outcomes were also evaluated at 3–15 months follow-up after loading. At 3–6 months reentry, all shields were stable with maintenance of the facial bone and with extreme hard tissue formation in the sockets. All five implants were successful and functional without any pain or inflammation, with optimal soft tissue health and esthetics, and with minimal radiographic marginal bone loss at the last follow-up visit (3–15 months after loading).

Conclusions

Within the limits of this study, socket shield technique with delayed implant placement could be a predictable minimally invasive option for cases requiring delayed implant placement; however, a long-term well-designed clinical proof is warranted.

Dimensional Changes in the Alveolus after a Combination of Immediate Postextraction Implant and Connective Grafting and/or Socket Shield Technique

Immediate implant placement protocols after dental extraction have enabled a reduction in surgical phases. This procedure has increased patient satisfaction and similar survival rates to late implant placement procedures. However, placing an implant immediately after dental extraction does not counteract the physiological remodeling of alveolar bone. For this reason, additional surgical techniques have been developed, such as the placement of a connective tissue graft (CTG) or the socket shield technique (SST). Dimensional changes in the peri-implant tissues were observed after placement of immediate implants following the extraction and CTG and/or SST. A total of 26 surgical interventions were carried out in which dimensional change variables of peri-implant tissues were analyzed. The preoperative state and immediate postoperative situation were compared with the situation after one year. Measurements were taken at 3, 5, and 7 mm from the gingival margin and analyzed in this CBCT radiological study (Planmeca Promax 3D). The implant platform was used as a reference point for the measurement of changes in alveolar crest height. One year after performing either of the two techniques (CTG and/or SST), a significant increase in the gingiva thickness and vestibular cortex occurred at 5 mm (0.65 ± 1.16 mm) and 7 mm (0.95 ± 1.45 mm) from the gingival margin. Additionally, an increase in thickness of palatal bone was registered at 3 mm (0.48 ± 0.90 mm). The graft placement group showed an increase in thickness of peri-implant tissue in the vestibular area after one year, although CTG and SST groups were clinically similar. The implementation of SST revealed promising results regarding the buccal thickness of hard and soft tissues after one year. A significant increase in vestibular cortical bone thickness, as well as the overall mucosa thickness and buccal bone at 3 mm from the gingival margin, was observed. A significant reduction in the distance from the bone crest to the platform was detected in both techniques. Both techniques (CTG and SST) are appropriate to provide sufficient volume to peri-implant tissues in the vestibular area of anterior maxillary implants. Some limitations were detected, such as the lack of an aesthetic analysis or small sample size, so results should be interpreted with caution. Future studies are necessary to further evaluate the long-term predictability of these techniques.

Immediate Implants in the Aesthetic Zone: Is Socket Shield Technique a Predictable Treatment Option? A Narrative Review

(1) Background. Dental implant placement in the anterior region requires extreme precision due to relatively high aesthetic demand. This narrative review aimed to analyse some of the available clinical studies of the socket-shield technique and determine its viability for dental implant survival/success and complication rates. (2) Methods. An electronic search for publications was performed using the Cochrane, PubMed-MEDLINE, Web of Science, and Google Scholar databases. All electronic searches included human clinical and animal studies and were performed by three independent examiners. (3) Results. A total of 1383 records were identified with the initial search strategies, but only 25 full texts + five abstracts clinical studies were kept after the recruitment criteria screening. The technical details, advantages, and limitations of the techniques were illustrated. (4) Conclusion. Within the limitations of the present review, it would be merely justified that immediate dental implant placement in conjunction with the socket-shield technique can be a promising strategy for dental implant therapy.

Comparison of the soft and hard peri-implant tissue dimensional changes around single immediate implants in the esthetic zone with socket shield technique versus using xenograft: A randomized controlled clinical trial

OBJECTIVE

Compare the dimensional changes of the peri-implant soft and hard tissues clinically and radiographically around single immediate implants in the esthetic zone with socket shield technique versus filling the buccal gap with xenograft.

MATERIALS AND METHODS

Forty-two patients with a single non-restorable tooth in the esthetic zone replaced with an immediate implant were randomly assigned either to the socket shield technique (test) or to grafting the buccal gap with xenograft (control). The vertical and horizontal buccal bone resorption were measured 6-months following implant placement. The esthetic outcomes were evaluated by assessing the Pink Esthetic Score (PES) and the amount of midfacial mucosal alteration, in addition to patient satisfaction assessment through a Visual Analogue Scale (VAS) based questionnaire 1-year following implant restoration.

RESULTS

The present study showed that the socket shield group yielded significantly less vertical and horizontal buccal bone resorption of 0.35 (±0.62) mm and 0.29 (±0.34) mm compared to 1.71 (±1.02) mm and 1.45 (±0.72) mm in the xenograft group respectively. Also, there was a significantly greater midfacial mucosal recession in the xenograft group of 0.466 (±0.58) mm compared to midfacial mucosal coronal migration of 0.45 (±0.75) mm in the socket shield group. However, there was no statistically significant difference regarding the total PES and patient satisfaction in both treatment groups.

CONCLUSION

The socket shield technique can preserve hard and soft peri-implant tissues following immediate implant placement. (ClinicalTrials.gov Identifier: NCT03684356).

The socket-shield technique: a critical literature review

Introduction

Dental implants have become a standard treatment in the replacement of missing teeth. After tooth extraction and implant placement, resorption of buccal bundle bone can pose a significant complication with often very negative cosmetic impacts. Studies have shown that if the dental root remains in the alveolar process, bundle bone resorption is very minimal. However, to date, the deliberate retention of roots to preserve bone has not been routinely used in dental implantology.

Material and methods

This study aims to collect and evaluate the present knowledge with regard to the socket-shield technique as described by Hurzeler et al. (J Clin Periodontol 37(9):855-62, 2010). A PubMed database search (www.ncbi.nlm.nih.gov/pubmed) was conducted to identify relevant publication.

Results

The initial database search returned 229 results. After screening the abstracts, 13 articles were downloaded and further scrutinised. Twelve studies were found to meet the inclusion and exclusion criteria.

Conclusion

Whilst the socket-shield technique potentially offers promising outcomes, reducing the need for invasive bone grafts around implants in the aesthetic zone, clinical data to support this is very limited. The limited data available is compromised by a lack of well-designed prospective randomised controlled studies. The existing case reports are of very limited scientific value. Retrospective studies exist in limited numbers but are of inconsistent design. At this stage, it is unclear whether the socket-shield technique will provide a stable long-time outcome.

The (in)adequacy of translational research in dentistry

Translational research, as the name suggests, "translates" research findings into clinical practice to improve the health of human beings. The translational process builds on information from experiments conducted at a basic level (i.e., in vitro and/or animal studies) and progresses over experimental human studies for efficacy, efficiency, and safety to implementation. Therefore, all steps in the process should be based on studies conducted with the highest methodological quality possible in order to provide accurate and useful information. Furthermore, the systematic dissemination of new procedures/techniques should be done only when they have been proven to be effective and safe. This focus article describes examples of new techniques/procedures in dentistry that have not resulted from an adequate translational research process since the initial evidence was published. These procedures are generally characterised by lack of good evidence, particularly on their potential harms, and lack of adequate chronological order, regarding the translational research process (i.e., human research being conducted before animal research). Even so, they seem to be widely disseminated, and their promotion involves a wide range of sources, including social media. Some guidance is proposed to improve the quality of the translational research process in dentistry, as well as the level of awareness of all parties involved with the use of this research: clinicians, researchers, and patients. By improving the translational research process, optimization of the application and use of these resources, with less risk to the patients, is expected.

[Clinical evaluation of the socket-shield technique for immediate implantation in the maxillary anterior region]

OBJECTIVE

This study aimed to evaluate the clinical effect of the socket-shield technique in the maxillary anterior region at one year after implant placement.

METHODS

Ten patients with maxillary anterior teeth that cannot be reserved were enrolled. Implants were installed following the socket-shield technique and restored six months after the surgery. The thickness of the labial maxillary bone of the implant was compared before and one year after the surgery. At one year follow-up, the reten-tion rate of the implants, Jemt classification, and pink and white aesthetic scores were evaluated. Postoperative complications and patient satisfaction were also analyzed.

RESULTS

One year after installation, the retention rate of the implant was 100%. The thickness of the maxillary bone at the neck, central, and root section of the implant reduced to (0.27±0.21), (0.19±0.20), and (0.28±0.29) mm, respectively, compared with the values immediately after the operation. The thickness of the labial maxillary bone at the three measurement points immediately after and one year after the operation was statistically significant (P<0.05). No significant difference (P>0.05) of the difference thickness between immediate and one year after operation at the three measurement points. The pink esthetic scores of the implant prosthesis was 9.10±0.54, and the white esthetic scores was 9.00±0.63. No complications were observed, and the patients had a high degree of satisfaction.

CONCLUSIONS

The socket-shield technique could provide acceptable treatment results but cannot completely avoid the reconstruction of the labial maxillary bone of the implants. The technique exhibits favo-rable short-term aesthetic result, but its long-term clinical effect and aesthetic problems need to be further studied.

Socket-shield technique for implant placement to stabilize the facial gingival and osseous architecture: A systematic review

The aim of the present study was to establish the efficacy of the socket-shield technique (SST) for the stabilization of the facial gingival and osseous architecture. An electronic search including the Cochrane databases, EBSCOhost, Medline/PubMed and Web of Science was performed. Articles related to SST for placing dental implants were included. Articles and abstracts not written in English were excluded. The initial literature search resulted in 113 articles related to questions raised. Hand searching of the journals related to implants and cross-referencing related to SST within the selected articles resulted in 1 more paper. Finally, 20 full texts and abstract of 1 article were included in the present systematic review: 11 case reports, 6 case series, 1 human randomized control trial (RCT), 1 technical report and 2 animal RCT. Recent modifications in SST, along with long follow-up studies with increased sample size, provided promising results. This systematic review still recommends that SST should not be used in routine clinical practise until a higher level of evidence established. Further RCT on SST are required to establish the clinical efficacy of this technique.

Application of cell-sheet engineering for new formation of cementum around dental implants

Periodontal disease involves the chronic inflammation of tooth supporting periodontal tissues. As the disease progresses, it manifests destruction of periodontal tissues and eventual tooth loss. The regeneration of lost periodontal tissue has been one of the most important subjects in periodontal research. Since their discovery, periodontal ligament stem cells (PDLSCs), have been transplanted into periodontal bony defects to examine their regenerative potential. Periodontal defects were successfully regenerated using PDLSC sheets, which were fabricated by cell sheet engineering in animal models, and for which clinical human trials are underway. To expand the utility of PDLSC sheet, we attempted to construct periodontal tissues around titanium implants with the goal of facilitating the prevention of peri-implantitis. In so doing, we found newly formed cementum-periodontal ligament (PDL) structures on the implant surface. In this mini review, we summarize the literature regarding cell-based periodontal regeneration using PDLSCs, as well as previous trials aimed at forming periodontal tissues around dental implants. Moreover, the recent findings in cementogenesis are reviewed from the perspective of the formation of further stable periodontal attachment structure on dental implant. This mini review aims to summarize the current status of the creation of novel periodontal tissue-bearing dental implants, and to consider its future direction.

The Root Membrane Technique: A Retrospective Clinical Study With Up to 10 Years of Follow-Up

PURPOSE

Immediate implant placement in conjunction with intentional root retention is a recently introduced technique, but the majority of existing documentation is limited to short-term reports with low level of evidence. Hence, the aim of this study was to document the long-term clinical and radiographic results of the root membrane technique.

METHODS

This retrospective study reports on clinical results of the root membrane technique for periodontal ligament-mediated immediate implant placement with up to 10 years of follow-up from 3 private dental practices. Anterior implants placed with immediate loading from January 2006 to December 2016 were assessed. Kaplan-Meier estimators were computed for reporting of implant success and survival.

RESULTS

A sample of 182 patients (82 men and 100 women, age range: 18-83 years) received 250 immediate implants (230 maxilla, 20 mandible) after the root membrane concept and followed-up for a mean of 49.94 months (±32.5). Overall, 5 implant failures were recorded for a 10-year cumulative patient-level implant survival rate of 96.5%. Considering mechanical and biological complications, the 10-year cumulative implant success rate was 87.9%.

CONCLUSIONS

Within the limits of the retrospective design, the root membrane technique showed long-term success rates comparable to those of conventional immediate implants.

Socket Shield: A Case Report

It is fairly common to remove a severely compromised tooth and provide rehabilitation by means of an implant. Resorption of alveolar bone after extraction resulting in loss of bone height and width is an unpleasant sequelae causing difficulty in implant placement. Few procedures have been promoted to attain the required bone height and width, such as guided bone regeneration socket preservation with the use of various graft materials and barrier membranes. The disadvantages of these techniques are some amount of ridge height loss and loss of buccal/facial, ridge contour. The socket shield technique is a new method where a buccal segment of root is retained as a shield, which aids in retaining periodontal ligament on buccofacial aspect. The implant is placed (immediate placement) lingual to this shield. This maintains the alveolar ridge height and buccofacial contour, thus providing superior aesthetics. This case report shows placement of an implant in upper anterior region using this technique.

Clinical Application of the Socket-Shield Concept in Multiple Anterior Teeth

A case of rehabilitation of the upper front teeth is presented. To prevent bone resorption following extractions, a socket-shield technique on all the extracted teeth was performed. The combination of a staged extraction approach, the sequence of provisionals together with the minimal bone loss of vestibular volume, allowed solving this high aesthetic demanding case in a satisfactory way for the patient both in duration of the treatment and in its final outcome.