Fresh extraction socket: spontaneous healing vs. immediate implant placement

Application of Immediate Implant Placement Techniques in Peri-implantitis Modeling

OBJECTIVES

To explore the use of immediate implant placement technique in peri-implantitis modeling, shorten the modeling period, and obtain similar effects.

MATERIALS AND METHODS

Eighty rats were divided into 4 groups: immediate placement (IP), delayed placement (DP), IP-ligation (IP-L) and DP-ligation (DP-L). In the DP and DP-L groups, implants were placed 4 weeks after tooth extraction. In the IP and IP-L groups, implants were placed immediately. Four weeks later, the implants were ligated to induce peri-implantitis in the DP-L and IP-L groups.

RESULTS

Nine implants were lost (3 in the IP-L and 2 each in the IP, DP, and DP-L group). The bone level decreased after ligation, and the buccal and lingual bone levels were lower in IP-L versus DP-L. The implant pullout strength was decreased after ligation. Micro-CT showed bone parameters were decreased after ligation, and the percent bone volume was higher in IP versus DP. Histology showed that the percent of CD4 + cells and IL-17 + cells was increased after ligation and higher in IP-L versus DP-L.

CONCLUSIONS

We successfully introduced immediate implant placement into the modeling of peri-implantitis and observed similar bone resorption and more soft tissue inflammation in a shorter time.

Critical review on bone grafting during immediate implant placement

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

Accuracy of keyless vs drill-key implant systems for static computer-assisted implant surgery using two guide-hole designs compared to freehand implant placement: an in vitro study

PURPOSE

This in vitro study aimed at comparing the accuracy of freehand implant placement with static computer-assisted implant surgery (sCAIS), utilizing a keyless and a drill-key implant system and two guide-hole designs.

METHODS

A total of 108 implants were placed in 18 partially edentulous maxillary models simulating two different alveolar ridge morphologies. 3D digital deviations between pre-planned and post-operative implant positions were obtained. Guide material reduction was assessed in the keyless implant system for the manufacturer's sleeve and sleeveless guide-hole designs.

RESULTS

sCAIS using a sleeveless guide-hole design demonstrated smaller mean angular, crestal and apical deviations compared to sCAIS utilizing a manufacturer's sleeve and the freehand group (2.6 ± 1.6°, vs 3.3 ± 1.9°, vs 4.0 ± 1.9°; 0.5 ± 0.3 mm, vs 0.6 ± 0.3 mm, vs 0.8 ± 0.3 mm; and 1.0 ± 0.5 mm, vs 1.2 ± 0.7 mm, vs 1.5 ± 0.6 mm). Smaller angular and apical mean deviations were observed in the keyless implant system as compared with the drill-key implant system (3.1 ± 1.7°, vs 3.5 ± 1.9°, p = 0.03; and 1.2 ± 0.6 mm, vs 1.4 ± 0.7 mm, p = 0.045). Overall, smaller angular, crestal, and apical deviations (p < 0.0001) were observed in healed alveolar ridges (2.4 ± 1.7°, 0.5 ± 0.3 mm, and 0.9 ± 0.5 mm) than in extraction sockets (4.2 ± 1.6°, 0.8 ± 0.3 mm, and 1.6 ± 0.5 mm). Higher mean volumetric material reduction was observed in sleeveless than in manufacturer's sleeve guide-holes (- 0.10 ± 0.15 mm³, vs - 0.03 ± 0.03 mm³, p = 0.006).

CONCLUSIONS

Higher final implant positional accuracy was observed in sCAIS for the keyless implant system, with a sleeveless guide-hole design, and in healed ridges. Sleeveless guide holes resulted in higher volumetric material reduction compared with the manufacturer's sleeve.

Therapeutic Efficacy of Bromelain in Alveolar Ridge Preservation

Most of research in regenerative oral surgery describes materials or techniques for increasing volumetric results for implant-supported prosthesis. The use of bio-materials in alveolar ridge preservation after tooth extraction commonly leads to a delayed recovery. Bromelain is an enzyme that belongs to a family of proteolytic enzymes derived from the stem of the pineapple plant (Ananas comosus) with effectiveness in decreasing the inflammation development and swelling. The present paper reports a prospective comparative study performed in order to test the possible use of oral bromelain 40 mg in alveolar ridge preservation. Evaluations were performed at three time points after the surgery: after 2 days (t1), after 7 days (t2) and after 14 days (t3). A statistically significant difference among patients that used bromelain and patients that used placebo resulted among the use of bromelain and lower Visual Analogue Scale (VAS) at t1 (r = -0.75, p = 0.0067), t2 (r = -0.90, p = 0.0001) and t3 (r = -0.8566, p = 0.0008). Bromelain therapy reported a statistically significant difference among patients that used bromelain and patients that used placebo even with regards to the use of bromelain and postoperative swelling at t1 (r = -0.79, p = 0.0034), t2 (r = -0.81, p = 0.0020) but not at t3 (r = -0.34, p = 0.2967). With the result of the present paper, and the poorness of contraindication of the investigated drug, bromelain may be suggested to be used for patients that undergo to alveolar ridge preservation after tooth extraction.

Soft and hard tissue changes after immediate implant placement with or without a sub-epithelial connective tissue graft: results from a 6-months pilot randomized controlled clinical trial

AIM

The present pilot RCT aimed to investigate the influence of a connective tissue graft (CTG) in combination with the immediate implant placement (IIP) on hard and soft tissues healing, without a bone replacement graft in the gap between the implant and the socket walls.

MATERIAL AND METHODS

Thirty patients requiring extraction of one anterior tooth (from premolar to premolar) were randomly assigned to one of the two treatment groups (test: IIP+CTG; control: IIP). Cone-beam computed tomography (CBCT) and optically scans were performed before tooth extraction and at 6-months follow-up. Then, DICOM files were superimposed in order to allow the evaluation of osseous ridge and buccal bone changes, while the superimposition of DICOM and STL (Standard Tessellation Language) files allowed for evaluating of soft tissue contour. For testing the differences between the two groups, the non-parametric test as Wilcoxon rank-sum test, was used.

RESULTS

Twenty-six out of the thirty enrolled patients, attended the 6-month follow-up visit. The 4 patients of control group that were lost to follow-up, were analyzed under the intention-to-treat principle. No statistically significant differences between the groups were observed for the vertical buccal bone resorption (p=0.90), as well as for the horizontal buccal bone resorption at all measured levels. Significant differences were found between test and control groups in the horizontal dimensional changes of osseous ridge at the most coronal aspect (p=0.0003 and p=0.02). Changes of tissue contour ranged between -0.32 and -0.04 mm in the test group, and between -1.94 and -1.08 mm in the control group, while changes of soft tissue thickness varied between 1.33 and 2.42 mm in the test group, and between -0.16 and 0.88 mm in the control group, with statistically significant differences for both variables at all measured levels. At 6 months, the mean volume increase was 6.76±8.94 mm³ and 0.16±0.42 mm³ in the test and control groups, respectively, with statistically significant difference.

CONCLUSIONS

The findings of the present study indicate that the adjunct of a connective tissue graft at the time of immediate implant placement, without bone grafting, does not influence vertical bone resorption. Within the limits of the present study, it can be suggested that the adjunct of a connective tissue graft at the time of immediate implant placement, without bone grafting, reduces the horizontal changes of the alveolar ridge. Moreover, it allows maintenance of the tissue contour due to an increase in soft tissue thickness.

Programmed core-shell electrospun nanofibers to sequentially regulate osteogenesis-osteoclastogenesis balance for promoting immediate implant osseointegration

The biology of immediate post-extraction implant osseointegration is mediated by a coordinated cascade of osteoblast-osteoclast interactions. The aim of this study was to develop a dual-delivery system that allowed sequential release of substance P (SP) to promote bone regeneration and alendronate (ALN) to reduce bone resorption, which will improve the implant osseointegration. We used coaxial electrospinning to fabricate the core-shell poly lactic-co-glycolic acid (PLGA)/gelatin nanofibers, which consists of SP in the shell and ALN in the core. This programmed delivery system was shown to release SP and ALN sequentially to match the spatio-temporal specificity of bone healing. The migration assay demonstrated that the SP-ALN dual-delivery system increased bone marrow mesenchymal stem cells (BMSCs) transmigration. Besides, the expression of osteogenic/osteoclastic markers, Alizarin Red staining, tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining and bone resorption experiment showed that the dual-delivery system can render a microenvironment favorable for osteogenic differentiation and adverse to osteoclastogenesis. Using a rat immediate implant model, we validated the promoted osteogenic property and osseointegration around the implants of SP-ALN dual-delivery system by micro-computed tomography (micro-CT) and histological analysis. These findings suggest that the dual-delivery system with time-controlled release of SP and ALN by core-shell nanofibers provides a promising strategy to facilitate immediate implant osseointegration through favorable osteogenesis. STATEMENT OF SIGNIFICANCE: Immediate implant placement is potentially challenged by the difficulties in achieving primary implant stability and early osteogenesis. Initial period of osteointegration is regulated by osteoblastic/osteoclastic cells resulting in a coordinated healing process. To have an efficient bone regeneration, the coaxial electrospinning was used to fabricate a programmed dual-delivery system. The SP released rapidly and favored for BMSCs migration and osteogenic differentiation, while the sustained release of ALN can reduce the bone resorption. The rat immediate implant model indicated that the SP-ALN dual-delivery system could present the promoted peri‑implant osteogenic property and osseointegration through modulating the osteogenesis-osteoclastogenesis balance. This work highlights the sequential dual delivery of SP and ALN has a promising potential of achieving enhanced osseointegration for immediate implant placement.

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.

Comparison of clinical esthetic outcomes of immediately placed implants with and without immediate provisionalization in single-tooth implants of the esthetic area: A protocol for systematic review and meta-analysis

BACKGROUND

Immediately placed implants with immediate provisionalization have become attractive options for patients and clinicians. However, there is no agreement on the esthetic advantages of immediately placed implants with immediate provisionalization. The aim of this systematic review and meta-analysis will be to assess the effect of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants in a single-tooth implant of the esthetic area.

METHODS

An electronic search of MEDLINE/PubMed, EMBASE, Web of Science, Clinicaltrials.org., Cochrane Library, China Biology Medicine (CBM), Wan Fang Database, China National Knowledge Infrastructure Database (CNKI), and VIP Science Technology Periodical Database will be performed. The search will be carried out in the databases for articles published until May 2021. Two researchers will independently perform the literature selection, data extraction and quality assessment. Only randomized controlled trials (RCTs) reporting on the impact of immediate provisionalization on the clinical esthetic outcomes of implants immediately placed in a single-tooth implant of the aesthetic area will be included. The primary outcome of this study will be the esthetic outcome assessed by the objective index and patient satisfaction. The survival rate of implants and restorations and the changes in mucosa and bone around implants will also be analyzed. The included studies will be analyzed by Review Manager 5.3, and a meta-analysis will be performed.

RESULTS

The study will evaluate the clinical esthetic outcomes of immediately placed implants with and without immediate provisionalization in single-tooth implants of the esthetic area. The results will provide clinicians with a better treatment approach in their application.

CONCLUSION

This systematic review and meta-analysis will provide more reliable, evidence-based data for the impact of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants, which may or may not be beneficial.

REGISTRATION NUMBER

PROSPERO registration number: CRD42021221669.

Effect of different platelet-rich fibrin matrices for ridge preservation in multiple tooth extractions: A split-mouth randomized controlled clinical trial

AIM

To evaluate dimensional changes in the alveolar ridge and bone structure after tooth extraction when L-PRF or A-PRF+ was used in comparison to unassisted socket healing.

MATERIALS AND METHODS

Twenty patients in need of at least three tooth extractions in the aesthetic zone were included. L-PRF, A-PRF+ or control was randomly assigned, leaving one empty socket/edentulous site between conditions. CBCT scans were obtained immediately after tooth extraction and after 3 months of healing. Horizontal and vertical dimensional changes of the ridge and socket fill were calculated. Histological and micro-CT analysis of bone biopsies were used to evaluate post-surgical bone structural healing.

RESULTS

Mean horizontal and vertical changes at 1-mm below the crest (buccal and palatal side) were similar for the three sites (p > 0.05). For the socket fill, L-PRF (85.2%) and A-PRF+ (83.8%) showed superior values than the control (67.9%). The histological and radiological analysis reported more newly formed bone for the PRF groups, without any significant differences between both.

CONCLUSIONS

PRF matrices failed to reduce the dimensional changes after multiple tooth extractions in the premaxilla. After 3-month healing, both PRF matrices showed radiographically a significant superiority for the socket fill. Histologically, they seemed to accelerate new bone formation.

Aesthetic outcomes of non-functional immediately restored single post-extraction implants with and without connective tissue graft: A multicentre randomized controlled trial

OBJECTIVES

To compare the 1-year aesthetic results of flapless single implants, placed in fresh extraction sockets with bone replacement and immediate provisional restoration with or without a connective tissue graft (CTG).

MATERIAL AND METHODS

The present study proposes a partially blinded multicentre parallel randomized controlled trial, where computer-generated tables were used for central randomization to allocate treatments. A total of 59 of the 60 patients screened by eight private practices in Northern Italy fulfilled the inclusion criteria. Immediate implants were placed in a fresh extraction socket with a non-functional immediate provisional restoration with (Test group) or without (Control group) a CTG. The primary outcome variable was the implant Crown Aesthetic Index (ICAI) at the 1-year follow-up.

RESULTS

ICAI for the 59 randomized patients (Test group = 31, Control group = 28) at the 1-year follow-up was 4.69 (95% CI = 3.16-6.22) for the Test group and 3.45 (95% CI = 1.83-5.08) for the Control group, without statistically significant difference between the two groups (p = .086). One implant failure was recorded in each group, resulting in an implant survival rate of 96.8% [95% CI = 83.3-99.9] for the Test group and 96.4% [95% CI = 81.7-99.9] for the Control group. Other secondary outcome variables and complication rates were comparable across the two groups.

CONCLUSIONS

Within the limitations of the present clinical trial, the results suggested that the adjunct use of CTG is not mandatory to achieve successful aesthetic outcomes for a well-planned immediate implant placement with immediate non-functional provisional restoration in a fresh extraction socket.

Postextraction Ridge Width Alterations Following Socket Seal Surgery—A Retrospective Study

Background and objectives: Preservation of alveolar ridge contour following tooth extraction is important to allow for restoration with prosthetics and implants. Socket seal surgery was introduced more than two decades ago for preservation of the form, volume and bone quality of the postextraction ridge. The aim of this retrospective study was to assess the changes in alveolar ridge contour following socket seal surgery and to evaluate the survival of the soft tissue grafts sealing the extraction site. Materials and Methods: Digital images of the extraction sites treated with the socket seal surgery were obtained immediately after extraction and after a healing time of 6 months to measure the changes in the alveolar width. In addition, the sites were photographed 1 week postsurgery to evaluate the vitality of the soft tissue grafts. Results: The overall mean loss of buccal width following socket seal surgery was 5.3% (SD = 13.4%). The mean change in width at the incisor area (1.5% ± 13.1) was significantly lesser than those in the canine area (−17.0% ± 2.1, p < 0.01) or premolar area (−10.5% ± 11.2, p < 0.01). One-week post-surgery 69% of the grafts were vital, and 31% were partially vital. Complete necrosis of the grafts did not occur. Conclusions: Our results suggest that socket seal surgery has a beneficial effect on alveolar dimensional changes 6 months following tooth extraction and that the teeth that benefit mostly from socket seal surgery are incisors.

The effect of immediate implant placement on alveolar ridge preservation compared to spontaneous healing after tooth extraction: Soft tissue findings from a randomized controlled clinical trial

AIM

To compare soft tissue dimensional changes and relative differences in soft and hard tissue volumes 4 months after single-tooth extraction and three different treatment modalities: spontaneous healing (SH) and alveolar ridge preservation by means of a deproteinized bovine bone mineral and a collagen matrix, with (IMPL/DBBM/CM) or without (DBBM/CM) immediate implant placement.

MATERIALS AND METHODS

STL files from study casts obtained at baseline and after 4 months were matched to calculate buccal soft tissue linear and volumetric changes. DICOM files from CBCTs were superimposed to STL files allowing the evaluation of soft tissue thickness at baseline and 4 months.

RESULTS

Mean horizontal reduction accounted for 1.46 ± 0.20 (SH), 0.85 ± 0.38 (DBBM-CM) and 0.84 ± 0.30 IMPL/DBBM-CM, with no statistical differences. Soft tissue thickness had a significant mean increase of 0.95 for SH group, compared to a non-significant mean decrease for DBBM-CM (0.20) and IMPL/DBBM-CM groups (0.07).

CONCLUSION

A preservation technique with DBBM-CM, with or without immediate implant placement, did not reduce the horizontal linear and volumetric changes at the buccal soft tissue profile significantly at 4 months after tooth extraction when compared to spontaneous healing. This is due to a significant increase in soft tissue thickness in spontaneously healing sites.

Anti-resorptive effect of pamidronate on extraction socket wall in dogs

AIM

The aim of this experimental in vivo investigation was to assess the anti-resorptive effect of low concentration pamidronate on the buccal plate in fresh extraction sockets.

MATERIALS AND METHODS

The distal roots of the third premolars were extracted bilaterally in six dogs. A collagen matrix loaded with either pamidronate (test group) or saline (control group) was positioned on the outer surface of buccal bone immediately after tooth extraction and subsequently covered with a coronally advanced flap. Histological and histomorphometric outcomes were evaluated 12 weeks later.

RESULTS

The mean vertical distance between the buccal and lingual bone crest differed significantly between the test and control groups (0.52 ± 0.43 and 2.21 ± 1.15 mm, respectively; p = .037). The width of the buccal bone 1 mm below the crest was significantly wider in the test group than the control group (4.68 ± 0.68 vs. 3.44 ± 0.60 mm, p < .001).

CONCLUSIONS

Local application of pamidronate onto a collagen matrix may reduce the dimensional changes of the buccal bone plate both vertically and horizontally.

Characterization of the Correct Mandibular Premolar Region for Delayed Dental Implantation in Beagle Dogs

For delayed dental implantation into the mandible, the implant size should be chosen according to the characteristics of that bone. This study investigated anatomic features of the mandible in beagle dogs, to develop recommendations regarding the correct implantation region and available bone area for delayed dental implantation surgery. We used 20 healthy male beagle dogs to create delayed dental implantation models. The dogs' mandibles underwent cone beam CT (CBCT) imaging; the locations of the middle mental foramen and canine root apex were measured on CBCT images. The dogs then were euthanized and their mandibles measured by using a digital vernier caliper. In addition, the correct implantation region and available bone areas were evaluated. The data obtained by using the 2 measuring methods were compared statistically. The results showed that the positions of the middle mental foramen and canine root apex were relatively fixed, with little variation. The implantation and available bone regions showed little variation among dogs and did not differ significantly between the 2 measuring methods. In conclusion, the correct implantation region (mean ± 1 SD) in the beagle mandible for delayed dental implantation surgery was 17.53 ± 0.46 mm in width. The recommended available bone areas (height × width) were 7.22 ± 0.68 mm × 5.32 ± 0.49 mm (P2), 8.21 ± 0.71 mm × 5.81 ± 0.56 mm (P3), and 9.17 ± 0.65 mm × 6.39 ± 0.56 mm (P4) in the premolar region.

Case Selection is Critical for Successful Outcomes Following Immediate Implant Placement in the Esthetic Zone

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Immediate versus delayed implant placement after anterior single tooth extraction: the timing randomized controlled clinical trial. Tonetti MS, Cortellini P, Graziani F, Cairo F, Lang NP, Abundo R, Conforti GP, Marquardt S, Rasperini G, Silvestri M, Wallkamm B, Wetzel A. Journal of Clinical Periodontology 2017;44(2):215-24.

SOURCE OF FUNDING

Nonprofit, Foundations: European Research Group on Periodontology, Genova, Italy Industry: Thommen Medical AG, Switzerland and Geistlich AG, Switzerland (biomaterials).

TYPE OF STUDY/DESIGN

Randomized controlled trial.

An immediate peri-implantitis induction model to study regenerative peri-implantitis treatments

OBJECTIVES

The aim of this study was to evaluate the validity of the immediate peri-implantitis model to test regenerative therapies in peri-implantitis defects.

MATERIAL AND METHODS

In an immediate peri-implantitis model in beagles, the mandibular third premolars were extracted, and dental implants were immediately placed in the distal extraction sockets. Without a healing period, experimental peri-implantitis was induced by ligature placement for 3 months. In the conventional peri-implantitis model, dental implants were placed in the healed mandibular fourth premolar region and were submerged for osseointegration. After 3 months of healing, peri-implantitis induction was performed for another 3 months. After peri-implantitis defects were formed in both models, regenerative therapy was performed in both models.

RESULTS

After 3 months in the immediate model and 9 months in the conventional model, similarly shaped horizontal bone defects (wide and craterlike) were observed. However, buccal bone defects were deeply formed in the immediate model compared with the conventional model (6.02 ± 1.20 and 4.34 ± 0.86 mm, respectively; P = 0.009), but the amounts of bone regeneration were not significantly different between the models (P = 0.107). On the lingual side, re-osseointegration was significantly greater in the conventional model than in the immediate model (0.72 ± 0.50 and 1.77 ± 0.87 mm, respectively; P = 0.009), although lingual bone defects were not significantly different between the models (P = 0.248).

CONCLUSIONS

Although the immediate peri-implantitis model is challenging for regeneration, it may be able to replace the conventional model to study regenerative peri-implantitis treatment due to its short experimental time and similar defect configuration.

Key local and surgical factors related to implant failure

The concept of osseointegration has revolutionized the treatment options for the replacement of missing teeth in both partially and completely edentulous patients. Dental implants are widely used because clinical practice and studies have documented its successful outcomes. However, implants can occasionally fail, and such failures can be classified as early or late. Measures that can aid in the early recognition of failing osseointegrated implants are needed, as are measures that can facilitate appropriate treatment methods aimed at saving failing implants by determining the probable etiologic factors. This article summarizes our current understanding of the local factors that can be linked to implant failure.