The effect of the heights and thicknesses of the remaining root segments on buccal bone resorption in the socket-shield technique: An experimental study in dogs

Modified Surgical Guide for Root Sectioning in the Socket Shield Technique-In Vitro Study

OBJECTIVE

This in vitro study aimed to evaluate the effectiveness of a printed surgical guide for root sectioning in the socket-shield technique.

MATERIALS AND METHODS

A typodont model of the maxilla with augmented filler was used for the upper right central incisor, and CBCT images were obtained. Two types of vertical root sectioning guides were tested: one with a buccal sleeve (Group A, n = 10) and another with a buccal orientation slit (Group B, n = 10). Control group (n = 10) performed freehand cuts on printed models. After crown cutting with diamond burs, root sectioning was conducted using an ultrasonic tip with the guides. Mean and standard deviation were calculated for the remaining root length, width, and volume. Data were analyzed using the Kruskal-Wallis test and Dunn's post hoc test.

RESULTS

Statistical analysis showed significant differences in root width between the control group (2.0 mm) and both Groups A (2.655 mm; p < 0.0001) and B (2.460 mm; p < 0.0001). Group B (5.585 mm) also showed a significant difference in root remnant compared with the control (13.880 mm; p < 0.0043). Groups A and B did not differ significantly from each other.

CONCLUSIONS

The socket shield technique is safe and effective, this study aimed to add improvements through the introduction of surgical guides, facilitating the root section, which is the critical phase so that the parameters that are requisite for success are achieved in terms of width, length, and volume of the root remnant. Both guided techniques effectively facilitated root sectioning, maintaining satisfactory root thickness and length.

CLINICAL SIGNIFICANCE

Sectioning the root is challenging for the correct angulation to remove the palatal portion in the socket shield technique. Therefore, modifying this technique with the use of the presented guides, it is possible to prevent damage to the soft tissues and to plan the surgery with the help of cone beam computed tomography (CBCT) scans to remove the root apex and maintain the root remnant with a thickness greater than 1.5 mm, making the socket-shield technique more predictable.

Biomechanical characteristics of maxillary anterior incisor, conventional immediate implantation and socket shield technique - A finite element analysis and case report

BACKGROUND

To prevent the absorption and collapse of the labial bone plate of the anterior teeth, immediate implantation and socket shield technique have been increasingly applied to anterior dental aesthetic implant restoration.

OBJECTIVE

To provide a biomechanical basis for implant restoration of maxillary anterior teeth, finite element analysis was used to investigate the stress peak and distribution in different anatomical sites of natural teeth, conventional immediate implantation and socket shield technique.

METHODS

Three maxillary finite element models were established, including a maxillary incisor as a natural tooth, a conventional immediate implantation and a socket shield technique. A mechanical load of 100 N was applied to simulate and analyze the biomechanical behavior of the root, periodontal ligament (PDL), implant and surrounding bone interface.

RESULTS

The stress distribution of the natural tooth was relatively uniform under load. The maximum von Mises stress of the root, periodontal ligament, cortical bone and cancellous bone were 20.14 MPa, 2.473 MPa, 19.48 MPa and 5.068 MPa, respectively. When the conventional immediate implantation was loaded, the stress was mainly concentrated around the neck of implant. Maximum stress on the surface of the implant was 102 MPa, the cortical bone was 16.13 MPa, and the cancellous bone was 18.29 MPa. When the implantation with socket shield technique was loaded, the stress distribution of the implant was similar to that of immediate implantation. Maximum stress on the surface of the implant was 100.5 MPa, the cortical bone was 23.11 MPa, the cancellous bone was 21.66 MPa, the remaining tooth fragment was 29.42 MPa and the periodontal ligament of the tooth fragment was 1.131 MPa.

CONCLUSIONS

1. Under static loading, both socket shield technology and conventional immediate implantation can support the esthetic restoration of anterior teeth biomechanically. 2.Under short-term follow-up, both immediate implant and socket shield technology achieved satisfactory clinical results, including bone healing and patient satisfaction. 3.The stress distribution is mainly located on the buccal bone surface of the implant and is associated with resorption of the buccal bone plate after implant replacement in both socket shield technology and conventional immediate implantation. 4.The presence of retained root fragment had an impact on the bone graft gap. In immediate implantation, the peak stress was located in the cortical bone near the implant position, while in socket shield technology, the peak stress was at the neck of the cortical bone corresponding to the retained root fragment.

Self-designed surgical guides for accurate socket shield preparation: An in vitro evaluation supported by a clinical report

PURPOSE

To achieve accurate socket shield preparation with newly proposed guides that are based on guiding rails and to investigate the effect of rail format (unilateral or bilateral) and rail height on the accuracy and efficiency of the guides.

MATERIALS AND METHODS

Two surgical guides based on grooved rails to guide the rotary instruments were produced. The first guide was used to cut the root into a labial shield with a pre-designed form and a lingual one, while the second guide was used to reduce the socket shield to the alveolar bone crest. The CBCT and intraoral scan data were first obtained and superimposed using the software. After isolating the root which would be used as a socket shield, grooved rails were designed on two separate guide templates according to the chosen rotary instruments to obtain a labial shield with a pre-designed form. An in vitro study was then conducted based on four cases in each group to determine the accuracy, efficiency, and optimal parameters of the guides, which was then verified with a clinical report. Comparisons between groups were performed with a one-way analysis of variance (ANOVA, for comparison between multiple groups) and the Student-Newman-Keuls test (for comparison between two groups).

RESULTS

With these two guides, the root can be divided into two pieces, including a palatal one and a labial one with a pre-designed form within a short time. Guide templates with bilateral rails more than 7 mm in height and those with unilateral rails 9 mm in height significantly increased the surgery accuracy, showing accurate shield preparation and decreased bone injury. Moreover, the guides with bilateral rails of more than 5 mm significantly decreased the surgery time for shield preparation. The presented case further verified the accuracy and efficiency of the guides.

CONCLUSIONS

The newly proposed guides can help to accurately prepare the socket shield, resulting in long-term stability of peri-implant tissues. Moreover, bilateral guiding rails with a height of 7-9 mm are recommended in such a guided socket shield surgery.

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.

Five-Year Clinical, Radiographic, and Cone-Beam Follow-Up of Socket Shield Technique in Two Cases Treated with a Split Mouth Design

The two presented cases of socket shield technique were done following a split mouth protocol in two patients, each received an immediate implant inserted conventionally on maxillary one side and another implant inserted applying the socket shield technique on the contralateral side. The outcomes including soft and hard tissue changes were compared clinically and radiographically. The four implants were followed for 5 years, and the outcomes were successful.

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.

Socket shield technique: Stress distribution analysis

Background

To analyze through finite element analysis the stress distribution in peri-implant bone tissues, implants, and prosthetic components induced by the socket shield (SS) technique in comparison to other techniques used to treat tooth loss.

Materials and Methods

A three-dimensional model of a superior central incisor crown supported by implant was modeled and three different placement conditions were simulated: SS - 2.0-mm-thick root dentin fragment positioned between the alveolar buccal wall and implant; heterologous bone graft (HBG) - bovine bone graft positioned the alveolar buccal wall and implant; and control (C) - implant fully placed in bone tissue of a healed alveolus. The model was restricted at the lateral surfaces of the bone tissue and the following loads were simulated: Both oblique (45°) loads of 100 N on the lingual surface of the crown (maximal habitual intercuspation) and 25.5 N on the incisal edge of the crown (tooth contact during mandibular protrusion) were simultaneously applied. Tensile stress, shear stress, compression, and displacement were analyzed in the cortical bone, trabecular bone, dentin root fragment, and bone graft; while equivalent von Mises stresses were quantified in the implant and prosthetic components.

Results

Stress values of SS and HBG in the bone tissues were higher than C, while slight differences within models were observed for dentin root fragment, bone graft, implant, and prosthetic components.

Conclusions

The SS technique presented the highest stress concentration in the peri-implant tissues.

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.

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.

Navigation guided socket-shield technique for implant and pontic sites in the esthetic zone: A proof-of-concept 1-year prospective study with immediate implant placement and loading

OBJECTIVE

To assess clinical, radiological performance of novel navigation guided socket-shield technique (NSS) with immediate implant placement and loading.

MATERIALS AND METHODS

Eighteen patients (12 females; age 52.54 ± 4.92; 33-72) treated between January 2018 and June 2019, were investigated, and followed for at least 1 year after definitive prosthesis placement (mean 20.1 months, 18-23). Primary outcomes: implant and prosthetic success rates, surgical, biologic, prosthetic complications.

SECONDARY OUTCOMES

marginal bone loss (MBL), implant stability quotient (ISQ), pink esthetic score (PES), plaque and bleeding indexes.

RESULTS

Sixty-nine navigation guided socket-shield procedures were performed (27 implant-sites and 42 pontic-sites) and 27 implants (NobelParallel, NobelBiocare AG) positioned and immediately loaded. Mean insertion torque and ISQ at implant positioning were 49 ± 5.34 Ncm (36-74), 73 ± 5.72 (68-81). No implant failure was experienced. Two root-shield exposures with mucositis, ulceration and bleeding were reported at two pontic-sites (2.9%) and successfully treated. No complications were experienced at implant-site leading to an overall NSS success-rate of 100%. No prosthetic complications occurred. Mean MBL was -0.72 ± 0.26 mm (-0.42 to -1.06 mm). PES final at the last follow-up 12.84 ± 0.92. The plaque and bleeding scores were 18.5 ± 6.12 and 3.15 ± 2.21.

CONCLUSIONS

Within study limitations, dynamic navigation was effective to streamline execution of socket-shield technique at implant and pontic sites, shortening treatment time and reducing complications. Navigation guided socket-shield technique was reliable to achieve digitally planned shield-to-implant distance, facilitate immediate implant placement and loading and establish the mucosal dimension needed for underlying bone-to-implant protection and esthetic integration.

CLINICAL SIGNIFICANCE

The investigated NSS technique overcomes the difficulties related to root preparation at implant and pontic-sites, facilitating immediate implant placement and loading. Dynamic guided surgery contributed to make socket-shield technique less technical-sensitive, shortening time for execution, reducing complication rate.

Efficacy of platelet-rich fibrin in promoting the healing of extraction sockets: a systematic review

PURPOSE

To address the focused question: in patients with freshly extracted teeth, what is the efficacy of platelet-rich fibrin (PRF) in the prevention of pain and the regeneration of soft tissue and bone compared to the respective control without PRF treatment?

METHODS

After an electronic data search in PubMed database, the Web of Knowledge of Thomson Reuters and hand search in the relevant journals, a total of 20 randomized and/or controlled studies were included.

RESULTS

66.6% of the studies showed that PRF significantly reduced the postoperative pain, especially in the first 1-3 days after tooth extraction. Soft tissue healing was significantly improved in the group of PRF compared to the spontaneous wound healing after 1 week (75% of the evaluated studies). Dimensional bone loss was significantly lower in the PRF group compared to the spontaneous wound healing after 8-15 weeks but not after 6 months. Socket fill was in 85% of the studies significantly higher in the PRF group compared to the spontaneous wound healing.

CONCLUSIONS

Based on the analyzed studies, PRF is most effective in the early healing period of 2-3 months after tooth extraction. A longer healing period may not provide any benefits. The currently available data do not allow any statement regarding the long-term implant success in sockets treated with PRF or its combination with biomaterials. Due to the heterogeneity of the evaluated data no meta-analysis was performed.

Pre-Clinical Models in Implant Dentistry: Past, Present, Future

Biomedical research seeks to generate experimental results for translation to clinical settings. In order to improve the transition from bench to bedside, researchers must draw justifiable conclusions based on data from an appropriate model. Animal testing, as a prerequisite to human clinical exposure, is performed in a range of species, from laboratory mice to larger animals (such as dogs or non-human primates). Minipigs appear to be the animal of choice for studying bone surgery around intraoral dental implants. Dog models, well-known in the field of dental implant research, tend now to be used for studies conducted under compromised oral conditions (biofilm). Regarding small animal models, research studies mostly use rodents, with interest in rabbit models declining. Mouse models remain a reference for genetic studies. On the other hand, over the last decade, scientific advances and government guidelines have led to the replacement, reduction, and refinement of the use of all animal models in dental implant research. In new development strategies, some in vivo experiments are being progressively replaced by in vitro or biomaterial approaches. In this review, we summarize the key information on the animal models currently available for dental implant research and highlight (i) the pros and cons of each type, (ii) new levels of decisional procedures regarding study objectives, and (iii) the outlook for animal research, discussing possible non-animal options.

Socket shield technique: A systemic review and meta-analysis

PURPOSE

The aim of the present study was to evaluate the clinical feasibility of the socket shield technique (SST).

STUDY SELECTION

An electronic search of the PubMed, Cochrane Central Register of Controlled Trials, and Wiley Online Library databases, and a manual reference search for articles published up to September 2020 was conducted. Meta-analysis was performed to estimate marginal bone loss (MBL), changes in buccal bone width (cBBW), pink esthetic score (PES), implant stability quotient (ISQ), implant failure rate, and complication rate between SST and conventional immediate implant placement (IIP). All pooled analyses were based on random effects models.

RESULTS

Sixteen relevant studies were ultimately selected by two independent reviewers: four randomized clinical trials (RCTs), four case-control studies, and eight retrospective studies. Meta-analysis revealed a trend toward lower MBL and cBBW and higher PES in the SST group. ISQ, implant failure rate, and complication rate were similar between the groups.

CONCLUSIONS

The included studies provided evidence that SST may be a feasible treatment option. However, this technique should not be used as a routine clinical protocol due to the lack of evidence-based consensus guidelines, large-scale RCTs, and long-term follow-up data. Therefore, there is an urgent need for well-conducted RCTs in this field.

Fate of root shell after pontic/socket shield techniques, is it better to extract the whole tooth?

A series of changes occur in the remaining alveolar process after whole tooth extraction. The basic question is, why do the bony walls (especially the labial/buccal) get resorbed immediately after the tooth is removed? This could be because, with cementum of the concerned tooth and its periodontal ligament, the supporting bundle bone is dependent on the presence of the tooth. This loss can be compensated using numerous techniques, such as socket grafting using various biomaterials to preserve the alveolar bone and buccal grafting with guided tissue regeneration to increase the thickness of buccal bone or placement of implant immediately. However, none of these techniques prevent the modelling of the alveolar bone post-extraction. Few studies have demonstrated that preservation of the roots in the alveolar process maintains the bone volume and facilitates vertical bone growth. A histological study in animals and humans has shown that the retained root shell does not pose any interference in the osseointegration of the implant (if placed simultaneously). Although various names have been proposed to describe the concept of retaining full or part of the root to prevent the resorption of the ridge, socket-shield and pontic-shield are the two most commonly used terms worldwide. The extraction of the whole tooth might be the choice of therapy when socket-shield or pontic-shield is not possible due to anatomical variations, infections, or lack of clinical expertise. Irrespective of the size, when a whole root or a root fragment (is left in situ), it is the dentist’s ethical duty to advise/inform the patient and ensure repeated clinical and radiographic follow-up. The present study aimed to highlight the current status of these techniques, their benefits, and possible complications and address whether the paradigm of the teeth extraction methods should be altered.

Treating severe periodontitis with staged load applied implant restoration: A case report

BACKGROUND

Because immediate implant surgery is not recommended for patients who have been diagnosed with periodontitis, researchers have treated these patients with a variety of methods, including combining orthodontic and periodontal surgeries as well as implantation. However, these treatments cost time and money for the patient. Although it has been reported that temporary implants released a severe gag reflex in 1 case, only a few studies have documented using temporary implants to treat patients diagnosed with severe periodontitis.

CASE SUMMARY

The patient was a 49-year-old female who was missing the majority of her teeth and had gingival atrophy and severe alveolar bone atrophy. After being diagnosed with severe periodontitis, the patient underwent staged load applied implant restoration therapy. The first load-bearing stage was carried out immediately by inserting temporary Osstem mini implants. Maxillary teeth were extracted by using the guided bone regeneration technique, and lateral maxillary sinus lifting was conducted on both sides. During the second load-bearing stage, temporary implants were removed, and permanent implants were placed. The resin bridge was segmented during the third load-bearing stage. During the fourth load-bearing stage, the permanent prosthesis was positioned in the patient’s mouth.

CONCLUSION

By conducting the load-bearing treatment in stages, the patient’s mouth contained restorations throughout the procedure, thus guaranteeing basic function and appearance.

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.

CAD-CAM titanium preparation template for the socket-shield technique

The socket-shield technique can be challenging and time-consuming. This article presents a digital approach to fabricating a computer-aided design and computer-aided manufacturing (CAD-CAM) titanium preparation template for the socket-shield technique. Preoperative cone beam computed tomography (CBCT) was used to map the remaining root, and the desired shape of buccal fragment of the root was determined as the socket shield. A CAD-CAM titanium preparation template was fabricated to facilitate root sectioning and the preparation procedure for forming an adequate socket shield.

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.

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 technique: the influence of the length of the remaining buccal segment of healthy tooth structure on peri-implant bone and socket preservation. A study in dogs

OBJECTIVE

The aim of this study was to evaluate the influence of the location and length of root pieces on buccal peri-implant bone width and socket preservation in socket shield technique.

MATERIAL AND METHODS

Forty-eight dental implants (24 narrow and 24 regular platform internal hex implants) were placed in six dogs. The clinical crowns of teeth P2, P3, P4 and M1 were detached horizontally and removed from the underlying roots. Then the mesial root of each tooth was extracted and the distal root was degraded using a high-speed hand-piece with round bur, creating a concave shell of dentin cementum and periodontal ligament (PDL) connected to the buccal aspect of the socket. Remaining root fragments of different lengths were created: coronal (1/3); middle and coronal (2/3); full length (3/3). These were positioned all around the bone crest. Implants were placed at the center of the root sockets, 1-3mm deeper than the original root apex. RFA and histological evaluations were made at 4 and 12 weeks. Data underwent statistical analysis (p<0.05).

RESULTS

All 48 implants osseointegrated satisfactorily. On both buccal and lingual sides, the coronal (1/3) radicular fragment was attached to the buccal bone plate by physiologic periodontal ligament with less crestal bone resorption compared with middle (2/3) and whole root (3/3) groups for narrow and standard implants.

CONCLUSIONS

Within the limitations of this study, the results demonstrate that a small piece of root in the coronal part of the alveolus can protect the buccal, mesial and distal bone crest following the immediate placement of NeO narrow or NeO Standard Internal Hex implants. The thickness of peri-implant bone and the remaining root fragment together will provide a total thickness of >2mm. The technique would appear to be highly predictable, maintaining bone volume and reducing the risk of crestal bone resorption.