Assessing peri-implant bacterial community structure: the effect of microbiome sample collection method.

BACKGROUND: Oral microbiota comprises polymicrobial communities shaped by mutualistic coevolution with the host, contributing to homeostasis and regulating immune function. Nevertheless, dysbiosis of oral bacterial communities is associated with a number of clinical symptoms that ranges from infections to oral cancer. Peri-implant diseases are biofilm-associated inflammatory conditions affecting the soft and hard tissues around dental implants. Characterization and identification of the biofilm community are essential for the understanding of the pathophysiology of such diseases. For that sampling methods should be representative of the biofilm communities Therefore, there is a need to know the effect of different sampling strategies on the biofilm characterization by next generation sequencing. METHODS: With the aim of selecting an appropriate microbiome sampling procedure for periimplant biofilms, next generation sequencing was used for characterizing the bacterial communities obtained by three different sampling strategies two months after transepithelial abutment placement: adjacent periodontal crevicular fluid (ToCF), crevicular fluid from transepithelial abutment (TACF) and transepithelial abutment (TA). RESULTS: Significant differences in multiple alpha diversity indices were detected at both the OTU and the genus level between different sampling procedures. Differentially abundant taxa were detected between sample collection strategies, including peri-implant health and disease related taxa. At the community level significant differences were also detected between TACF and TA and also between TA and ToCF. Moreover, differential network properties and association patterns were identified. CONCLUSIONS: The selection of sample collection strategy can significantly affect the community composition and structure. TRIAL REGISTRATION: This research is part of a randomized clinical trial that was designed to assess the effect of transepithelial abutment surface on the biofilm formation. The trial was registered at Trial Registration ClinicalTrials.gov under the number NCT03554876.

Tooth autotransplantation as a pillar for 3D regeneration of the alveolar process after severe traumatic injury: A case report.

In dental traumatology, the loss of teeth and the supporting alveolar bone in children compromise the proper development of maxillofacial structures and also limit the solutions that can be offered. In this case report, multidisciplinary management is described of a child with a significant loss of alveolar bone and associated teeth due to a traffic accident at 8 years of age. The management involved staged teeth autotransplantation into surgically prepared sites with bone expanders, orthodontic treatment and dental implants. The 3D regeneration of the alveolar process was successfully stimulated by teeth autotransplantation. At the 4-year follow-up visit, evaluation of the autotransplanted teeth and the implants indicated a successful outcome for the patient.

Conservative Implant Removal for the Analysis of the Cause, Removal Torque, and Surface Treatment of Failed Nonmobile Dental Implants.

This study was performed to study the effect of implant surface treatment on the cause and removal torque of failed nonmobile implants. Implant explantation was achieved by the application of countertorque at the implant-bone interface. The explantation socket was examined carefully and curetted to remove any granulation tissue. Immediate implant placement was accomplished when primary stability could be achieved. Eighty-one patients were treated according to the described treatment protocol for the explantation of 158 nonmobile implants in the maxilla and the mandible. The patient's mean age was 62 ± 11 years. The main cause of implant explantation was peri-implantitis (131 implants; 82.9%) followed by malpositioning of the implants (22 implants; 13.9%). The explantation of 139 implants at 146 ± 5 Ncm was performed without the need for trephine bur. However, the use of trephine burs to cut into the first 3 to 4 mm was necessary in 19 explantations, and the removal torque was 161 ± 13 Ncm. All titanium plasma-sprayed implants were removed due to peri-implantitis at a significantly lower torque when compared to acid-etched, particle-blasted, and oxidized implants. The postoperative recovery of the patients was uneventful and the conservation of the available hard and soft tissues was successfully achieved. The protocol followed in this study could constitute a real alternative to other traumatic technique for the removal of failed implants and advanced stages of peri-implantitis. The type of implant surface treatment could influence the value of removal torque and the occurrence of peri-implantitis.

Rehabilitation of Atrophied Low-Density Posterior Maxilla by Implant-Supported Prosthesis.

The rehabilitation of edentulous posterior maxilla is a challenging task that could be complicated by the availability of low-density and reduced height of alveolar bone. Patients were enrolled in this study upon the presence of type IV bone and residual bone height <5 mm in posterior maxilla. Novel procedure for transalveolar sinus floor elevation was described to insert 10 short implants in 4 patients. Neither implant failure nor prosthetic failure was observed during a follow-up of 44 ± 3 months. Mesial bone loss of 0.5 ± 0.6 mm and a distal bone loss 1.3 ± 0.9 mm were measured after 35 ± 4 months of loading.

Nontraumatic Implant Explantation: A Biomechanical and Biological Analysis in Sheep Tibia.

Preclinical research in a sheep tibia model has been conducted to evaluate the underlying mechanisms of the nontraumatic implant explantation of failed implants, which allow placing a new one in the bone bed. Twelve dental implants were placed in sheep diaphysis tibia and once osseointegrated they were explanted using a nontraumatic implant explantation approach. Implant osseointegration and explantation were monitored by means of frequency resonance, removal torque, and angle of rotation measurement. The host bone bed and the explanted implant surface were analyzed by conventional microscopy and scanning electron microscope. Results show that osseointegration was broken with an angular displacement of less than 20°. In this situation the implant returns to implant stability quotient values in the same range of their primary stability. Moreover, the explantation technique causes minimal damage to the surrounding bone structure and cellularity. This nontraumatic approach allows the straightforward replacement of failed implants and emerges as a promising strategy to resolve clinically challenging situations.

Implant Site Under-Preparation to Compensate the Remodeling of an Autologous Bone Block Graft.

Autologous bone block grafting is an efficient technique to thicken an atrophied residual alveolar ridge. A variable degree of resorption, however, occurs due to graft remodeling. In this study, we hypothesize that under-preparation of implant socket would permit the dental implant to act as a bone expansor and thus compensate for the contraction in the augmented ridge width. For that reason, 10 patients received an autologous bone block graft that was obtained from the ramus of the mandible. Residual alveolar ridge width was measured on CBCT scans obtained before surgery (T0), after 2 months of healing (T1), after 4 months of healing just before implant placement (T2), and after 4 months of implant placement (T3). The thickness of the alveolar ridge was initially increased from 2.5 ±â€Š1.4 to 6.1 ±â€Š2.0 mm. Before implant insertion, this width was decreased to 5.6 ±â€Š2.1 mm. The last measurement after implant insertion indicated an increase to 7.3 ±â€Š1.8 mm. In comparison to the measurements at T1, a loss of about 0.5 mm of the augmented width occurred. But, this loss was compensated by an increment of 1.2 mm at T3 (after implant insertion) if related to the measurement at T1. Neither gingival dehiscence nor block exposure was observed. Within the limitations of this study, under-preparation of implant socket could make the ridge expansion possible during implant insertion and thus to compensate the remodeling of autologous bone block graft.

Replacement of missing posterior tooth with off-center placed single implant: Long-term follow-up outcomes.

STATEMENT OF PROBLEM: The distal offset placement of a single implant to replace a single tooth would overcome the shortcomings of the placement of a single wide implant in the posterior region. However, long-term evaluation is still-lacking. PURPOSE: The purpose of this study was to evaluate the long-term outcomes of patients treated with a single tooth restoration supported by a distal-offset placed implant. MATERIAL AND METHODS: Thirty-one patients with a single restoration supported by an off-center placed implant were evaluated. The patients' demographic data were described. The known implant length was used as a reference to calibrate the linear measurements on digital periapical radiographs. Implant details, survival, and prosthetic complications were analyzed. The implant survival rate was analyzed with the Kaplan-Meier method. RESULTS: Thirty-four implants were placed with a distal offset to support single-tooth restorations. Twenty patients were women, and patient age was 56 ± 12 years. The implants had a follow-up time from loading up to 10 years (average: 4 ± 3 years). Most of the implants were inserted in type II bone, and 85% were placed in the molar region. The distal offset placement of the implant and the selection of a wide-diameter implant resulted in a mesial bone loss of 0.85 ± 0.57 mm and distal bone loss of 0.83 ± 0.68 mm. One implant failed after 4 months from insertion, resulting in a cumulative survival rate of 97.1%. No prosthetic complications were registered. CONCLUSIONS: The distal offset placement of an implant is an efficient option for restoring a single missing posterior tooth when mesiodistal space is limited.

Clinical, radiographical, and histological outcomes of plasma rich in growth factors in extraction socket: a randomized controlled clinical trial.

OBJECTIVES: Platelet-rich plasma has been used in the treatment of extraction socket; however, randomized controlled clinical trial is still lacking to evaluate its effect on extraction socket healing. MATERIALS AND METHODS: Single center, assessor-blinded, parallel group, randomized controlled clinical trial was conducted. Sixty patients with indication of a simple one molar extraction in the mandible were randomized to receive plasma rich in growth factors (PRGF) or blood clot. A cross-stitch suture was placed in both groups. Clinical, radiographical, and histological assessments were performed during 10-12 weeks of follow-up. RESULTS: Cone beam CT analysis has shown that the percentage of patients where the sockets are regenerated at ≥75 % of the baseline volume was significantly higher in PRGF group (96.7 %) than the control group (45.5 %). Pain and inflammation (day 3 and day 7) have been significantly lower in PRGF group than the control group but not at day 15. Soft tissue healing scores have been significantly higher in the test group. No serious adverse events have been occurred in both groups. Histological analysis has indicated the presence of significantly thicker keratinized epithelium and significantly higher newly formed bone in the PRGF group. CONCLUSIONS: PRGF was associated with enhanced healing of extraction socket of mandibular molars throughout the observation period. CLINICAL RELEVANCE: Plasma rich in growth factors could be a useful tool to enhance the healing of extraction sockets by minimizing postoperative complications and stimulating the hard and soft tissues regeneration.

Implant-Guided Vertical Bone Augmentation Around Extra-Short Implants for the Management of Severe Bone Atrophy.

The purpose of this study is to describe the conservative treatment of severe vertical bone atrophy by combining the insertion of extra-short implants and implant-guided bone augmentation. For that, a low-speed drilling protocol was selected to facilitate the collection of bone particles and to maintain graft osteogenic properties. Extra-short implants were incompletely inserted because of the severe atrophy, and the denuded implant surface was covered by autologous bone particles held together by the adhesive properties of plasma rich in growth factors. The surgical site was then covered with resorbable fibrin membrane, and the flap was repositioned and sutured. Eight patients with a mean residual bone height of 4.19 ± 0.97 mm were treated according to the described treatment protocol. The distance between the implant shoulder and the bony crest was 1.77 ± 0.18, 2.16 ± 0.23, and 1.97 ± 0.26 mm at the mesial, central, and distal aspects, respectively. Vertical bone augmentation resulted in the coverage of 85% of exposed surface by stimulating 1.6 ± 0.5 mm of supra-alveolar bone growth. All 10 extra-short implants placed were successfully osseointegrated. After a mean of 5 ± 1.6 months, provisional screw-retained prostheses were placed. Within the limitations of this study, we conclude that the minimally invasive approach described may successfully rehabilitate extreme vertical bone atrophy in the posterior mandible.