A prospective study on ultra-wide diameter dental implants for immediate molar replacement

Bone formation in large/moderate gap after immediate implantation in response to different treatments: a pre-clinical study in the canine posterior mandible

OBJECTIVES

This study aims to investigate different treatments on new bone formation around immediate implants in the canine posterior mandible with varying sized mesial-distal gap.

MATERIALS AND METHODS

The 4th premolar and the 1st molar of six Labrador dogs were extracted from the mandible, and 4 dental implants were placed 1 mm below the level of the buccal bone crest. Moderate/large mesial-distal gaps between the implants and the sockets were treated with one of four methods and divided into the following groups: (1) the blank group, (2) the collagen membrane (CM) group, (3) the deproteinized bovine bone mineral (DBBM) group, and (4) the DBBM + CM group. Sequential fluorescent labeling was performed at 4, 8, and 10 weeks after the operation. After 12 weeks, the dogs were euthanized, and specimens were collected for micro-CT scanning and histological analysis.

RESULTS

The survival rate of immediate implant was 100%. Micro-CT showed significant differences in bone mineral density (BMD) and bone volume fraction (BVF) among groups (P = 0.040, P = 0.009); other indicators were not significantly different among groups. Histological analysis showed the proportion of new bone formation and bone-to-implant contact were not significantly different among groups. No significant difference in bone reduction height around dental implant among four groups and varied mesial-distal gap size.

CONCLUSION

Owing to the restricted sample size, this pilot study lacks conclusive findings. Within the limitation, this study demonstrated that although DBBM significantly increase BMD and BVF, the use of DBBM/CM didn't significantly improve bone formation and healing in extraction sockets around the implants in both moderate and large mesial-distal gap.

CLINICAL RELEVANCE

The use of deproteinized bovine bone in conjunction with collagen is a common practice in immediate implantation procedures in the posterior mandible. However, there is a lack of conclusive evidence regarding the timing and circumstances under which they should be employed.

Agglomeration effect on biomechanical performance of CNT-reinforced dental implant using micromechanics-based approach

Dental implants have long played an important role in restoring lost teeth, but there are still concerns about their durability and long-term success. Commercial dental implants have traditionally been made of metallic and ceramic materials like titanium and zirconia; however, each kind of material has restrictions regarding osseointegration and mechanical characteristics that differ between native bone and the implant material, limiting the implant's longevity and reliability. To address these concerns, this research explores the use of carbon nanotubes (CNTs) in restorative dentistry, their excellent properties make them an ideal candidate for promoting bone growth around implanted device and ensuring long-lasting success. The objective of this study was to understand how CNT properties when incorporated into the titanium matrix may be able to better adapt to the oral environment taking into consideration the CNT agglomeration effects when designing reinforced nanocomposite materials for dental implant. A mathematical formulation of the micromechanics model was developed and improved to extend its application for the case of CNT-based composite materials for dental implants. A three dimensional (3D) model of bone structure around the osseointegrated dental implant was established considering different compositions of implant material. Finite Element Analysis (FEA) were conducted to assess the aggregation effect of implant incorporating CNTs into the titanium matrix, considering CNTs with both spherical inclusions (CNT clusters), and randomly dispersive ones (CNTs) in the titanium matrix, on osseointegration and bone remodeling around the dental implant and supporting bone system over a period of 48 months. Firstly, the effects of CNT-Ti implantation on time-dependent performance are evaluated in a computational remodeling framework. Then, Von Mises equivalent stresses are investigated to evaluate the stress distributions and micromotions in jaw bones of loaded implant with different composition of prosthetic material. Three agglomeration patterns are considered, particularly without agglomeration (ζ = ξ), partial and complete agglomeration (ζ < ξ, ξ = 1). Further, the influence of CNTs volume fraction variation is taken into account to predict the mechanical response of the bony system after CNT-reinforced dental implantation. It can be inferred that the agglomeration of CNTs reduces the elastic stiffness of the matrix. This is due to the fact that when CNTs are agglomerated, the inter-tube contacts are reduced and the effective stiffness of the matrix is decreased.

Survival Rate of Ultrawide Diameter Implants Placed into Molar Postextraction Sockets and in Function for Up to 144 Months

PURPOSE

Innovations in macroimplant design, specifically ultrawide implants 7.0 mm or greater in diameter, have allowed immediate molar replacement. This is a retrospective study assessing the survival rates of ultrawide diameter implants (7.0, 8.0, 9.0 mm) immediately placed into molar extraction sockets. Implants were followed up to 144 months postplacement.

MATERIALS AND METHODS

A retrospective study was conducted of all patients treated in a private surgical practice between January 1, 2008 and December 31, 2020, who received ultrawide dental implants (7.0, 8,0, 9.0 mm.) placed immediately into molar extraction sockets. Wide diameter healing abutments were placed on all implants at the time of surgery. Abutments and crown restorations were fabricated after at least 4 months of unloaded healing. Patient age, sex, implant location and implant diameters were examined for survival. Insertion torque values at the time of placement and time in function were also evaluated. Biometric statistics were computed with p-values (<0.05. Descriptive and bivariate statistics were computed; p-values were set at 0.05.

RESULTS

Five hundred forty-four patients (225 males; 319 females) average age 62.5 years (range 27 to 95) had 563 implants placed. Five hundred thirty-five of five hundred sixty-three (535/563) implants survived; 28 failed [clinical survival rate (CSR) 95.03%]. Number and time in function were: 0 to 12 years 100%; 0 to 9 years 85%; 0 to 6 years 69%; 0 to 3 years 35% or 10 to 12 years 16%; 7 to 9 years 16%; 4 to 6 years 34%; 0 to 3 years 35%. No significant differences were found between sex and implant failures (p = 0.22). Maxillary (266/285; 93.3%) and mandibular (269/278; 96.8%) implant CSRs were not significantly different. Three implant diameters were used: 7.0 mm (206/563) [36.6%]; 8.0 mm (267/563) [47.4%]; 9.0 mm (90/563) [15.9%]. Clinical survival rates were: 7.0 mm (201/206) [97.6%]; 8.0 mm (252/267) [94.4%]; 9.0 mm (82/90) [91.1%]. Mean age for patients with failed implants did not show any significant differences (p = 0.1398). Fifteen of the 28 failed implants failed within 120 days of surgical placement (prior to definitive restoration; [53.6%]; 4 implants failed between 4 and 12 months [14.3%]; 9 implants failed at least 1-year postloading [32.1%].

CONCLUSIONS

The results of this long-term retrospective study regarding ultrawide diameter implants suggested that these implants were viable treatment options for immediate molar replacement following tooth extraction in either jaw with an unloaded healing protocol. High clinical survival rates were reported over a 144-month (12-year) timeframe.

Morphological Characteristics of Maxillary Molars Interradicular Septum and Clinical Implications - What do We Know So Far?

The interradicular septum describes area in the root furcation that separate alveoli of multi-rooted teeth. The shape and dimension depend of the topography of the extraction socket, the geometry of residual root and anatomy of molars alveoli. The clinical implications of this anatomic structure may be used in oral surgery resection procedures, periodontology and implantology. There is an opinion from the surgical and prosthodontic side that center of interradicular septum may be adequate place for immediate implantation. The aim of this study was to investigate morphological characteristics and clinical implications of upper molars interradicular septum. The studies showed that interradicular septum is important for success of resection surgery procedures: hemi-section, bisection and root amputation. It’s reported that furcation involvement in periodontal disease is clinical sign for severe bone loss. By reviewing the available literature for immediate implantation, it’s reported the clinical implications for diagnostical plan (pre-intervention), presurgical (pre-instrumentation) and intraoperative evaluation of interradicular septum for immediate implantation. The cone beam computed tomography analyze study presented mean values of septum height and wide for hypothetical plan of immediate implant placement. The presurgical studies evaluate how to assure preservation of septum and safe implant position in center of septum. The research showed varies therapy modalities that can be used, and how to choose right therapy according the socket type and initial septum width classification. According to observation of studies results, other researches should be considered for CBCT anatomical structure analyze and measures of interradicular septum for immediate implantation planning.

Molar Septum Expansion with Osseodensification for Immediate Implant Placement, Retrospective Multicenter Study with Up-to-5-Year Follow-Up, Introducing a New Molar Socket Classification

The ideal positioning of immediate implants in molar extraction sockets often requires the osteotomy to be in the interradicular septum, which can be challenging in some cases, with traditional site preparation techniques. Patients who had undergone molar tooth extraction and immediate implant placement at five different centers, and followed up between August 2015 and September 2020, were evaluated. Inclusion criteria were use of the osseodensification technique for implant site preparation. The primary outcome was septum width measurement pre-instrumentation and osteotomy diameter post expansion. Clinical outcomes, such as implant insertion torque (ISQ) and implant survival rate, were also collected. A total of 131 patients, who received 145 immediate implants, were included. The mean overall septum width at baseline was 3.3 mm and the mean osteotomy diameter post instrumentation was 4.65 mm. A total of ten implants failed: seven within the healing period and three after loading; resulting in a cumulative implant survival rate of 93.1%. This retrospective study showed that osseodensification is a predictable method for immediate implant placement with interradicular septum expansion in molar extraction sockets. Furthermore, it allowed the introduction of a new molar socket classification. In the future, well-designed controlled clinical studies are needed to confirm these results and further explore the potential advantages of this technique.

Three-dimensional alveolar bone assessment of mandibular molars for immediate implant placement: a virtual implant placement study

Background

To elucidate the anatomical features of the mandibular molar region to allow safe immediate implant placement.

Methods

Cone-beam computed tomography images of 150 patients (600 teeth) were reviewed retrospectively. The virtual implants were placed in the mandibular first and second molar region. The anatomic structures of the mandible and inter-radicular septum were both categorized into three types. The relationship between implant and inferior alveolar nerve (IAN), and the horizontal distance from the implant surface to the bone wall were analyzed. Variables were compared using a student’s t-test, or Mann–Whitney U test.

Results

Type U (39.0%) and type S (56.0%) were the most common in the first molar, while type U (67.7%) and type M (54.7%) had the highest prevalence rate in the second molar. The mean distance from the level where the virtual implant was completely surrounded by bone to IAN was 7.06 mm. The mean horizontal widths from the implant to the mesial and distal socket wall were 1.59 mm and 1.89 mm. The widths of the inter-radicular septum and the distances from implant to the buccal and lingual plate on different sections were significantly associated with tooth position (P < .05).

Conclusions

In the first molar region, the implant is suggested to be placed in the center of the inter-radicular septum, while in the second molar region, the mesial root socket could be considered. Immediate implant placement in the mandibular second molar sockets shows a high risk of IAN injury, lingual perforation, and inadequate primary stability.

Clinical and esthetic outcomes of immediate implant placement compared to alveolar ridge preservation: a systematic review and meta-analysis

AIM

The aim of this systematic review was to evaluate the efficacy of immediate implant placement (IIP) compared to implants placed after alveolar ridge preservation (ARP) in terms of clinical, esthetic, and patient-reported outcomes.

METHODS

A manual and electronic search (National Library of Medicine) was performed for controlled clinical trials, with at least 12 months of follow-up. Primary outcome variable was implant survival and secondary outcomes were marginal bone level (MBL) (change), pink esthetic score (PES), mid-facial mucosal level (change), papilla index score, complications, and patient-reported outcomes.

RESULTS

A total of 10 publications were included (7 randomized clinical trials and 3 controlled clinical trials). The results from the meta-analyses showed that survival rate was significantly lower in the IIP group compared to ARP group [RR = 0.33; 95% CI (0.14; 0.78); p = 0.01]. No significant differences between the two groups were observed regarding radiographic MBL, PES scores, or mid-facial mucosal level (p > 0.05).

CONCLUSION

The results from this systematic review and meta-analysis showed that IIP had lower survival rates and similar esthetic results when compared to ARP.

CLINICAL RELEVANCE

Clinicians should weigh the benefits and disadvantages of each intervention to select the optimal timing of implant placement.

Immediate implant placement in molar extraction sockets: a systematic review and meta-analysis

Background

Immediate implants are frequently employed in the anterior maxillary area. However, the installation of dental implants simultaneously with tooth extraction can also provide with benefits in the posterior areas with a reduction in time prior the recovery of the masticatory function. Results previously reported in the literature show high-survival and success rates for implants placed in extraction sockets in molar areas; however, this topic has received limited systematic analysis.

Material and methods

Electronic and manual literature searches were performed by two independent reviewers in several data-bases, including MEDLINE, EMBASE, and Cochrane Oral Health Group Trials Register, for articles up to January 2019 reporting outcomes of immediate implants placed in molar areas. Primary outcomes included survival and success rates, as well as marginal bone loss. Secondary outcomes included the influence of implant position, type of implant connection, grafting protocol, flap or flapless approach, implant diameter, surgical phase, presence of buccal plate, and loading protocol.

Results

Twenty studies provided information on the survival rate, with a total sample of 1.106 implants. The weighted mean survival rate of immediate implants after 1 year of follow-up was 96.6%, and the success rate was 93.3%. On the other hand, marginal bone loss was 1.29 ± 0.24 mm. Secondary outcomes demonstrated that grafting the gap and the loading protocol have an effect on survival and success rates. Similarly, the presence or absence of the buccal bone affect crestal bone levels. Meta-analysis of 4 investigations showed a weighted mean difference of 0.31 mm ± 0.8 IC 95% (0.15–0.46) more marginal bone loss at immediate implant placement versus implants in healed sites (p < 0.001) I² = 15.2%.

Conclusion

In selected scenarios, immediate implant placement in molar extraction socket might be considered a predictable technique as demonstrated by a high survival and success rates, with minimal marginal bone loss.

Contour Changes Following Immediate Placement of Ultra-Wide Implants in Molar Extraction Sockets without Bone Grafting

The aim was to evaluate ridge reduction and mucosal recession following immediate placement of ultra-wide implants in molar sockets, without bone grafting. Impressions were taken prior to tooth extraction, 4 months and 1 year after implant placement. The casts were digitized and compared. Mucosal recessions and horizontal ridge reduction were measured. A total of 16 implants were in the maxilla and 11 in the mandible. At the buccal aspect, there was a mean reduction of 0.94 mm after 4 months and 0.89 mm after one year (p = 0.933). At the palatal/lingual aspect, this was 1.09 mm after 4 months and 0.69 mm after 1 year (p = 0.001). After 1 year, a recession of 0.59 mm was measured at the zenith, 1.04 mm at the mesial and 0.98 mm at the distal papilla. The mean midfacial horizontal ridge reduction was 1.23 mm after 4 months and 1.45 mm after 1 year. At the midpalatal/midlingual aspect, the mean horizontal reduction was 1.43 mm after 4 months and 1.16 mm after 1 year. Immediate implant placement without bone grafting in the posterior jaw yields a significant horizontal ridge reduction and minor mucosal recession. Clinicians should anticipate the amount of ridge reduction and consider augmentation at the time of implant placement.

Esthetic aspects in implant-prosthetic rehabilitation

The esthetic component is critical for the successful outcome and patients’ satisfaction regarding the implant-prosthetic therapy. The esthetic outcome success depends mostly on the optimization of the algorithms specific to the pro-implant and implant stage as well as to the designing and technological execution of the future prosthetic restoration. A proper planning of optimal facial esthetics must involve a multidisciplinary approach with inclusion of periodontists, orthodontists, oral surgeons and implantology specialists. The dental practitioner must consider various factors that influence the esthetic outcome (tooth position, root position of the adjacent teeth, biotype of the periodontium, tooth shape, smile line, implant site anatomy, implant positioning). Also, some factors (anatomical limits of the implant site, periodontal status, occlusal parameters), which can alter the final esthetic result, must be assessed prior to planning the esthetic parameters of the future prosthetic restoration. The esthetic outcome can be improved by using new digital technologies based on software applications for assessment of clinical and biological indices of the prosthetic field, virtual planning of implants positioning and design projection of future prosthetic restoration.

Optimized Dental Implant Fixture Design for the Desirable Stress Distribution in the Surrounding Bone Region: A Biomechanical Analysis

The initial stability of a dental implant is known to be an indicator of osseointegration at immediate loading upon insertion. Implant designs have a fundamental role in the initial stability. Although new designs with advanced surface technology have been suggested for the initial stability of implant systems, verification is not simple because of various assessment factors. Our study focused on comparing the initial stability between two different implant systems via design aspects. A simulated model corresponding to the first molar derived from the mandibular bone was constructed. Biomechanical characteristics between the two models were compared by finite element analysis (FEA). Mechanical testing was also performed to derive the maximum loads for the two implant systems. CMI IS-III active (IS-III) had a more desirable stress distribution than CMI IS-II active (IS-II) in the surrounding bone region. Moreover, IS-III decreased the stress transfer to the nerve under the axial loading direction more than IS-II. Changes of implant design did not affect the maximum load. Our analyses suggest that the optimized design (IS-III), which has a bigger bone volume without loss of initial fixation, may minimize the bone damage during fixture insertion and we expect greater effectiveness in older patients.

Finite Element Analysis of Novel Separable Fixture for Easy Retrievement in Case with Peri-Implantitis

Peri-implantitis is a common complication following dental implant placement, which may lead to bone loss and fixation failure. With the conventional fixture, it is difficult to perfectly clear-up the infection. To solve this, we have designed a separable fixture of which the top part is replaceable. This study aimed to compare the structural and biomechanical stability of the separable and conventional fixture. A single surgical model corresponding to the first molar in a virtual mandible model and conventional/separable implants were reproduced to compare the biomechanical characteristics of the implants using finite element analysis (FEA). The loading condition was 200N preload in the first step, and 100N (Axial), 100N (15°), and 30N (45°) in the second step. The stress distribution on the cortical bone in the separable implant was lower than the conventional implant. In particular, the Peak von Mises Stress (PVMS) values of the separable implant under lateral load was found to be about twice as low as that of the conventional implant. In this study, we suggest that the separable implant has an equivalent biomechanical stability compared to the conventional implant, is easy to retrieve in the case of peri-implantitis, and has an excellent initial stability after the surgery when used in stage 2.