Relationship between Implant Geometry and Primary Stability in Different Bony Defects and Variant Bone Densities: An In Vitro Study

Histological evaluation of osseointegration between conventional and novel bone-level tapered implants in healed bone-A preclinical study

AIMS

To histologically compare osseointegration and crestal bone healing between newly introduced tapered, self-cutting bone-level test implants and tapered bone-level control implants in sites with fully healed sites.

METHODS

Sixty-six implants (33 test, 33 control) were placed 1 mm subcrestally in a minipig model and underwent qualitative histologic and quantitative histometric analyses after 3, 6 and 12 weeks of submerged healing. The primary and secondary outcomes were the bone-to-implant contact (BIC) and first bone-to-implant contact (fBIC). Outcomes between the test and control implants were statistically compared.

RESULTS

The BIC values of the test implants were comparable and non-inferior over the time points studied, except for the 12 weeks time point which showed statistically significantly higher BIC values of the test (88.07 ± 5.35%) compared to the control implants (80.88 ± 7.51%) (p = .010). Similarly comparable and non-inferior were the fBIC values, except for the 6-week outcome, which showed statistically higher values for the test (-546.5 ± 450.80 μm) compared to the control implants (-75.7 ± 100.59 μm). fBIC results for the test implants were qualitatively more stable and consistent between test time points.

CONCLUSION

Novel self-cutting bone-level test implants demonstrated superior osseointegration and similar bone levels compared to conventional bone-level implants after a healing period of 12 weeks in healed ridges.

Dental Implant Placement in the Maxilla Following Ridge Augmentation with Free Iliac Bone Graft and Oral Rehabilitation with Fixed Prosthesis: a Three-Year Follow-Up Study

Objectives

This prospective follow-up study aimed to evaluate the stability values of tapered titanium implants inserted into maxilla following ridge augmentation with free iliac bone graft and crestal bone changes up to three years of follow-up.

Material and Methods

A total of seven patients with 34 tapered titanium implants in the maxilla with fixed protheses were enrolled in this prospective follow-up study. Patients with previously augmented maxillae using free iliac bone grafts were included. Implant stability was measured (Osstell™) for up to three months of healing. Peri-implant bone resorption was measured using radiographic images taken immediately after implant surgery and after three years. Using a clinical and radiological examination survival and success rates were evaluated.

Results

After implant insertion, the stability was 60.93, whereas the stability increased significantly (P = 0.0192) to 64.97 at implant exposure (after 3 months). The mean bone loss around the implants was 1.13 mm after three years. Clinical parameters revealed a mean sulcus depth of 2.76 (1.18) mm and a bleeding on probing score of 0.29 (0.58). The survival rate was 100%, and the success rate was 67.65% at the end of the study.

Conclusions

Tapered implants can be used in free iliac bone grafts for fixed dentures. Implant stability values were high after insertion. In terms of a success rate of 67.65%, the patient's jaw reconstruction indicated a reduced implant success when comparing the data with healthy patients without any augmentation procedures.

Significance of bone morphology and quality on the primary stability of orthodontic mini-implants: in vitro comparison between human bone substitute and artificial bone

AIM

This study evaluated artificial bone models against a human bone substitute to assess the primary stability of orthodontic mini-implants (OMIs) at varying implant sites with different morphologies and qualities.

MATERIALS AND METHODS

A total of 1200 OMI placements of four types were inserted into four artificial bone models of different density (D1, D2, D3, D4) and into a human bone substitute (HB). The implants varied in diameter (2.0 and 2.3 mm) and length (9 and 11 mm). Each specimen had four implant sites: no defect, one-wall defect, three-wall defect, and circular defect. The implant stability quotient (ISQ) values were measured using resonance frequency analysis (RFA) and insertion placement torque values (IPT) were assessed for primary stability. Correlation analysis was performed to evaluate the different models.

RESULTS

The highest IPT value was registered for the 2.0 mm × 11 mm implant inserted into D1 with no defect (37.53 ± 3.02 Ncm). The lowest ISQ value was measured for the 2.3 mm × 9 mm OMI inserted into D3 with a circular defect (12.33 ± 5.88) and the highest for the 2.3 mm × 9 mm implant inserted into HB with no defect (63.23 ± 2.57). A strong correlation (r = 0.64) for IPT values and a very strong correlation (r = 0.8) for ISQ values was found between D2 and HB.

CONCLUSION

Bone defects and bone quality affected the primary stability of implants in terms of ISQ and IPT values. Results for bone model D2 correlated very well with the HB substitution material.

Primary stability of implant placement and loading related to dental implant materials and designs: A literature review

A variety of implant placement and loading protocols are identified, ranging from immediate implant placement on the day of extraction to delayed placement for at least 6 months after complete healing. The method of assessment of implant placement and loading plays an important role in the implantation. The expected clinical outcomes depend largely on multiple factors, such as the macroscopic design of the implant, surgical technique, and the quality and quantity of local bone in contact with the implant, which would be described in detail. The purpose of this literature review was to explore the relationship between the factors influencing the implant placement stability and implant design. By understanding the original appearance of implant design and the stability requirements of implant placement, it is hoped that more research in the future can meet the needs of dentists and patients.

Insertion Torque and Resonance Frequency Analysis in Tapered and Parallel Dental Implants

Primary implant stability (PIS) is known to vary with recipient bone mass and density, dental implant design and surgical technique. The objective of this preliminary study was to compare rotational and lateral PIS of same-coronal-diameter conical and parallel implants, using insertion torque recorded with a dental implant motor set and implant stability quotient obtained from resonance frequency analysis (performed with both Osstell and Penguin systems) as measures of rotational and lateral stability, respectively. Additionally, the relationship between PIS and alveolar ridge width (ARW) was explored in both implant types. Sixty dental implants (30 tapered and 30 parallel) were randomly placed with a split-mouth design in 17 patients. Bone density and ARW were estimated from cone beam computed tomography images taken with radiological-surgical templates. Density and width values were similar in the 2 groups (P > .05). Implant coronal diameters were 3.75 mm in all cases, while consistent with the manufacturer's recommendations, final drill bit diameters used were 3.25 and 3.4 mm for parallel and tapered implants, respectively. Insertion torque was higher (P < .05) with parallel implants, but between-group differences in implant stability quotient were not significant (P > .05). In tapered implants, insertion torque was inversely correlated with ARW (P < .001). Notably, significant differences were observed between resonance frequency analysis values from Osstell and Penguin systems (P < .001). In conclusion, future studies should explore how PIS may be influenced by final drill bit size regardless of implant design and potential limits on the effectiveness of tapered implants to achieve good stability in thick low-density bone.

How does dental implant macrogeometry affect primary implant stability? A narrative review

PURPOSE

The macrogeometry of a dental implant plays a decisive role in its primary stability. A larger diameter, a conical shape, and a roughened surface increase the contact area of the implant with the surrounding bone and thus improve primary stability. This is considered the basis for successful implant osseointegration that different factors, such as implant design, can influence. This narrative review aims to critically review macro-geometric features affecting the primary stability of dental implants.

METHODS

For this review, a comprehensive literature search and review of relevant studies was conducted based on formulating a research question, searching the literature using keywords and electronic databases such as PubMed, Embase, and Cochrane Library to search for relevant studies. These studies were screened and selected, the study quality was assessed, data were extracted, the results were summarized, and conclusions were drawn.

RESULTS

The macrogeometry of a dental implant includes its surface characteristics, size, and shape, all of which play a critical role in its primary stability. At the time of placement, the initial stability of an implant is determined by its contact area with the surrounding bone. Larger diameter and a conical shape of an implant result in a larger contact area and better primary stability. But the linear relationship between implant length and primary stability ends at 12 mm.

CONCLUSIONS

Several factors must be considered when choosing the ideal implant geometry, including local factors such as the condition of the bone and soft tissues at the implant site and systemic and patient-specific factors such as osteoporosis, diabetes, or autoimmune diseases. These factors can affect the success of the implant procedure and the long-term stability of an implant. By considering these factors, the surgeon can ensure the greatest possible therapeutic success and minimize the risk of implant failure.

Results of thermal osteonecrosis for implant removal on electron microscopy, implant stability, and radiographic parameters - a rat study

BACKGROUND

This rat study aimed to evaluate the feasibility of temperature thresholds that affect peri-implant bone cells and morphology and the potential usefulness of thermal necrosis for inducing implant removal for a subsequent in vivo pig study.

METHODS

On one side, rat tibiae were thermally treated before implant insertion. The contralateral side was used as the control group without tempering. Temperatures of 4 °C, 3 °C, 2 °C, 48 °C, 49 °C, and 50 °C were evaluated with a tempering time of 1 min. Energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) analyses were performed.

RESULTS

The EDX analysis revealed significant increases in element weights at 50 °C (e.g., calcium, phosphate, sodium, and sulfur; p < 0.01). The results of the TEM analysis showed that at all the applied cold and warm temperatures, signs of cell damage were observed, including vacuolization, shrinkage, and detachment from the surrounding bone matrix. Some cells became necrotic, leaving the lacunae empty.

CONCLUSIONS

Temperature of 50 °C led to irreversible cell death. The degree of damage was more significant at 50 °C and 2 °C than at 48 °C and 5 °C. Although this was a preliminary study, from the results, we identified that a temperature of 50 °C at a time interval of 60 min can lower the number of samples in a further study of thermo-explantation. Thus, the subsequent planned in vivo study in pigs, which will consider osseointegrated implants, is feasible.

Dental implant failure rates with low insertion torque with a nonsubmerged surgical approach: A retrospective clinical study

BACKGROUND

It is currently unclear if a low insertion torque (IT) should prompt a clinician to submerge the dental implant at time of placement.

PURPOSE

This study aimed to analyze implant failure rates and marginal bone loss (MBL) as a function of IT and surgical approach.

MATERIALS AND METHODS

A total of 197 patients who had received 295 Mozo Grau (MG) implants were included in this study. The healing of submerged or nonsubmerged implants was evaluated in regular IT (≥20-25 Ncm) or low IT (<20-25 Ncm) cases. Implant failure and MBL were evaluated before prosthesis placement and at 6 and 12 months after functional loading with generalized estimating equations.

RESULTS

The overall 12-month implant failure rate was 4.8% (95% confidence interval [CI]: 2.7%-8.2%). When successful at 12 months, dental implants placed with low IT and nonsubmerging had the same MBL as implants dental implants placed with other approaches (mean difference = -0.02 mm; 95% CI -0.05 to 0.02). Low IT combined with nonsubmerging of the dental implant was associated with a 30-fold increased odds for dental implant failure (95% CI: 3.8-236.6).

CONCLUSION

low IT and nonsubmerged healing was associated with a high failure rate.

Esthetic and clinical outcomes after immediate placement and restoration: Comparison of two implant systems in the anterior maxilla-A cross-sectional study

AIM

To assess the esthetic and clinical performance of a novel self-tapping implant system for single-tooth restorations in the esthetic zone after immediate placement and provisionalization.

MATERIALS AND METHODS

This cross-sectional study included 52 patients contributing a total of 52 immediately placed and restored implants with ≥12 months after functional loading, comparing two different implant systems: Straumann® BLX (Institut Straumann AG, Basel, Switzerland; 25 patients) and Ankylos® (Dentsply Sirona, Hanau, Germany; 27 patients). As the primary outcome measure, peri-implant tissue esthetics were assessed by means of pink esthetics score (PES) rated by three independent clinicians. Moreover, as secondary outcome measures, the peri-implant tissue health was assessed by means of bleeding on probing, probing depth, and suppuration. Apart from that, the modified plaque index, keratinized mucosa width, and the presence of mucosal recessions were also assessed. When clinical signs suggested the possibility of peri-implantitis, radiographs were indicated to assess progressive bone loss.

RESULTS

The mean PES ratings were 12.10 ± 1.10 for Ankylos versus 11.2 ± 1.86 for BLX, both achieving good esthetic results without significant differences (p = 0.143). There were no differences among most clinical parameters (plaque, bleeding on probing, probing depth, peri-implant mucosal recession), although peri-implant mucositis was present in one-third of the cases. The inter-rater agreement on esthetics was not significant (p < 0.250).

CONCLUSION

Within the limitations of the present study, it was concluded that the use of either BLX or Ankylos implant systems was associated to comparable peri-implant health and good pink esthetic outcomes during immediate implantation and restoration protocols, for at least 12 months.

Dental Implant Placement in Focal Osteoporotic Bone Marrow Defect: a Case Report and Treatment Recommendations

BACKGROUND

Focal osteoporotic bone marrow defect is asymptomatic radiolucent area usually discovered incidentally during radiographic examination of the jaws. This bone condition can lead to clinical complications during dental implant placement or during osseointegration process.

METHODS

A 54-year-old woman was referred to private dental implant centre for a dental implant rehabilitation treatment in May 17, 2016. Oral examination revealed a healthy mucosa with no visible pathology. Adentia of tooth #46 and moderate atrophy of the edentulous alveolar process were found. Panoramic radiography of the jaws showed 2 cm x 2 cm radiolucency with irregular borders located in tooth #46 region. The margins of the bone defect were uneven, single trabeculae were visible, and the cortical layer was not deformed. In the absence of signs of pathology, it was decided to perform a dental implant surgery in the edentulous jaw segment #46.

RESULTS

The osteoporotic focus was filled with natural bovine bone substitute Cerabone^®. The granules were gently condensed to the sides - to the buccal and lingual walls until they filled the entire cavity. A 10 mm long, 4.1 mm diameter Straumann^® Tissue Level implant was surgically placed with the shoulder of the implant resting on the margins of the osteotomy. It was proposed six steps protocol for surgical dental implant installation in focal osteoporotic bone marrow defect in mandible.

CONCLUSIONS

A six-step protocol for surgical placement of dental implants in focal osteoporotic bone marrow defects may be a useful tool for clinicians in implant dentistry.

Influence of the Residual Ridge Widths and Implant Thread Designs on Implant Positioning Using Static Implant Guided Surgery

PURPOSE

Aggressive implant macrothread designs have been widely used. However, the effects of the aggressive thread design on the accuracy of static guided surgery, especially in a case of narrow residual ridge, have not been well-studied. The aim of this study was to evaluate the effects of two different implant macrothread designs and the residual ridge widths on the accuracy of tooth-supported static guided implant surgery.

MATERIALS AND METHODS

Forty implant fixtures with two different macrodesigns: a conventional thread design bone level tapered (BLT), and an aggressive thread design bone level tapered (BLX) were placed in 40 simulated polyurethane models with narrow and wide residual ridges. The placed implant positions were compared with the planned implant position and angulational deviation, as well as three-dimensional (3D) deviations at the entry and apex of the implant were measured. One-way ANOVA with Tukey's multiple comparisons (ɑ = 0.05) were used to determine level of significance between the mean and variance deviation values. 95% confidence intervals and box plots were used to demonstrate the means and ranges of precision.

RESULTS

In terms of angulational deviation, there was no statistically significant difference in the mean deviations for both types of implants, p = 1.55 and p = 0.84 for wide and narrow ridge groups, respectively. However, the range of deviation was much larger in the narrow ridge of the BLX group compared to the BLT group. In both narrow ridge and wide ridge, the BLX group had lower mean 3D deviation values at both the entry and the apex with statistically significant differences for both entry point of the wide ridge (p = 0.027) and narrow ridge (p = 0.022) as well as at the apex of the wide ridge (p = 0.006) but not the apex of the narrow ridge (p = 0.142).

CONCLUSION

The aggressive larger thread design of dental implants may influence the accuracy of implant placement more than the ridge dimension.

Primary Implant Stability Analysis of Different Dental Implant Connections and Designs-An In Vitro Comparative Study

Primary implant stability can be evaluated at the time of placement by measuring the insertion torque (IT). However, another method to monitor implant stability over time is resonance frequency analysis (RFA). Our aim was to examine the effect of bone type, implant design, and implant length on implant primary stability as measured by IT and two RFA devices (Osstell and Penguin) in an in vitro model. Ninety-six implants were inserted by a surgical motor in an artificial bone material, resembling soft and dense bone. Two different implant designs-conical connection (CC) and internal hex (IH), with lengths of 13 and 8 mm, were compared. The results indicate that the primary stability as measured by RFA and IT is significantly increased by the quality of bone (dense bone), and implant length and design, where the influence of dense bone is similar to that of CC design. Both the Osstell and Penguin devices recorded higher primary implant stability for long implants in dense bone, favoring the CC over the IH implant design. The CC implant design may compensate for the low stability expected in soft bone, and dense bone may compensate for short implant length if required by the anatomical bone conditions.

The primary stability of two dental implant systems in low-density bone

Primary stability in low-density bone is crucial for the long-term success of implants. Tapered implants have shown particularly favourable properties under such conditions. The aim of this study was to compare the primary stability of tapered titanium and novel cylindrical zirconia dental implant systems in low-density bone. Fifty implants (25 tapered, 25 cylindrical) were placed in the anterior maxillary bone of cadavers meeting the criteria of low-density bone. The maximum insertion (ITV) and removal (RTV) torque values were recorded, and the implant stability quotients (ISQ) determined. To establish the isolated influence of cancellous bone on primary stability, the implantation procedure was performed in standardized low-density polyurethane foam bone blocks (cancellous bone model) using the same procedure. The primary stability parameters of both implant types showed significant positive correlations with bone density (Hounsfield units) and cortical thickness. In the cadaver, the cylindrical zirconia implants showed a significantly higher mean ISQ when compared to the tapered titanium implants (50.58 vs 37.26; P < 0.001). Pearson analysis showed significant positive correlations between ITV and ISQ (P = 0.016) and between RTV and ISQ (P = 0.035) for the cylindrical zirconia implants; no such correlations were observed for the tapered titanium implants. Within the limitations of this study, the results indicate that cylindrical zirconia implants represent a comparable viable treatment option to tapered titanium implants in terms of primary implant stability in low-density human bone.

Endosseous Dental Implant Materials and Clinical Outcomes of Different Alloys: A Systematic Review

In recent years, implantology has made significant progress, as it has now become a safe and predictable practice. The development of new geometries, primary and secondary, of new surfaces and alloys, has made this possible. The purpose of this review is to analyze the different alloys present on the market, such as that in zirconia, and evaluate their clinical differences with those most commonly used, such as those in grade IV titanium. The review, conducted on major scientific databases such as Scopus, PubMed, Web of Science and MDPI yielded a startling number of 305 results. After the application of the filters and the evaluation of the results in the review, only 10 Randomized Clinical Trials (RCTs) were included. Multiple outcomes were considered, such as Marginal Bone Level (MBL), Bleeding on Probing (BoP), Survival Rate, Success Rate and parameters related to aesthetic and prosthetic factors. There are currently no statistically significant differences between the use of zirconia implants and titanium implants, neither for fixed prosthetic restorations nor for overdenture restorations. Only the cases reported complain about the rigidity and, therefore, the possibility of fracture of the zirconium. Certainly the continuous improvement in these materials will ensure that they could be used safely while maintaining their high aesthetic performance.

In vivo and in vitro analysis in a rat model using zoledronate and alendronate medication: microbiological and scanning electron microscopy findings on peri-implant rat tissue

Background

The aim of the present study was to assess the development of bacterial deposits and morphological parameters around dental zirconia and titanium implants compared with natural teeth during systemic bisphosphonate medication.

Materials and methods

Fifty-four rats were randomly allocated into one control group and two experimental groups (drug application of zoledronic and alendronic acid), with 18 animals in each group. After 4 weeks of drug delivery, either a zirconia or a titanium implant was immediately inserted. Microbiological analysis conducted 1 week, 8 weeks, and 12 weeks after surgery included total bacterial count and composition measurements. Samples were analyzed in a scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX). Bone cell morphology was analyzed by transmission electron microscopy (TEM).

Results

One week after surgery, titanium and zirconia implants of the alendronic acid and control group showed a significantly higher bacterial count when compared to natural teeth in rats with zoledronic acid administration (p < 0.01). Less significant differences were recorded after 3 months, at which time no inter-material differences were evaluated (p > 0.05). I n the control group, TEM analysis showed that the osteoblasts had a strongly developed endoplasmic reticulum. In contrast, the endoplasmic reticulum of the osteoblasts in drug-treated animals was significantly less developed, indicating less activity.

Conclusions

Within the limits of this study, neither implant material was superior to the other at 3-month follow-up. With regard to the treatment and complications of patients with bisphosphonates, the implant material should not be an influencing factor. Bisphosphonates can be used in the rat model to reduce not only the activity of osteoclasts but also osteoblasts of the peri-implant bone.

Zirconia vs. Titanium Dental Implants: Primary Stability In-Vitro Analysis

The present experimental trial uses two types of dental implants, one made of titanium (Ti₆A_l4V) and the other one of zirconia (ZrO₂), but both of identical design, to compare their stability and micro-movements values under load. One of each type of implant (n = 42) was placed into 21 cow ribs, recording the insertion torque and the resonance frequency using a specific transducer. Subsequently, a prosthetic crown made of PMMA was screwed onto each of the implants in the sample. They were then subjected to a static compression load on the vestibular cusp of the crown. The resulting micromovements were measured. The zirconia implants obtained a higher mean of both IT and RFA when compared with those of titanium, with statistically significant differences in both cases (p = 0.0483 and p = 0.0296). However, the micromovement values when load was applied were very similar for both types, with the differences between them (p = 0.3867) not found to be statistically significant. The results show that zirconia implants have higher implant stability values than titanium implants. However, the fact that there are no differences in micromobility values implies that caution should be exercised when applying clinical protocols for zirconia based on RFA, which only has evidence for titanium.

How to design a more stable dental implant: A topology optimization approach

The body shape design is one of the most influential factors in the success of dental implants. This study presents a strategy to design the geometrical features of a threaded implant. The topology optimization technique is applied to identify appropriate spaces in the implant body to be removed for bone growth. The exact shape, position, and dimensions of the spaces are determined using a finite element model. This model consists of a mandibular segment, implant, abutment, and crown. During the optimization process, some grooves and holes are created in the implant by removing redundant materials. Bone growth into these spaces causes mechanical locking between the implant and surrounding bone. The smoothing process is performed following the optimization to remove stress concentration. The results indicate that this design strategy reduces the maximum displacement of the implant by approximately 20%. Moreover, a reduction in the implant's volume and an increase in the contact area between the implant and bone are obtained. All mentioned issues would increase the stability and reduce the risk of implant loosening. Finally, using conventional production methods, the optimal implant was produced from titanium alloy to demonstrate the possibility of production of the proposed design.

Comparative assessment of the primary stability of Straumann® BLX implant design using an in-vitro sinus lift-simultaneous implant insertion model

Straumann ®  BLX is a novel implant system, which has been proclaimed to provide an ideal primary stability in all types of bone. In the current study, the primary stability of Straumann ®  BLX implant systems with Straumann ®  tapered effect (TE) implants have been comparatively assessed in bovine ribs by using a simultaneous sinus elevation and implant insertion model.  In the study group, BLX (4.0 x 12 mm), TE (4.1 x 12 mm), BLX (4,5 x 12 mm) and TE (4.8 x 12 mm) were placed in each bony window, which resembles sinus maxillaris. As a control, BLX and TE implants with same sizes were inserted into the proximal diaphysis of the bovine ribs. A total of 40 implant insertions were performed. The stability was measured with resonance frequence analysis. In the study group, TE implants of 4.8 mm showed significantly higher values compared to 4.5 mm BLX implants (p=0.116). However, BLX implants of 4.0 mm in the control group showed higher stability compared to TE with 4.0 mm diameter. (p=0.014).  The primary stability of BLX implants in the control group was significantly higher compared to the experimental group in both widths (p=0.018 for BLX 4.0 and p=0.002 for BLX 4.5 respectively). The use of TE design with wide diameter in simultaneous implant placement with sinus lift could present higher ISQ values and might be more appropriate option for implant recipient sites with poor bone volume and quality. However, the advantage of BLX design in standard implant insertion protocols could be precious.

An experimental study on the effects of the cortical thickness and bone density on initial mechanical anchorage of different Straumann® implant designs

Background

The aim of the current study was to comparatively assess the primary stability of different Straumann® implant designs (BLX, Straumann Tapered Effect, Bone Level Tapered, and Standard Plus) via resonance frequency analysis by using an implant insertion model in freshly slaughtered bovine ribs with and without cortical bone. Tapered Effect (4.1 × 10 mm), Bone Level Tapered (4.1 × 10 mm), Standard Plus (4.1 × 10 mm), and BLX (4.0 × 10 mm) implants were inserted into the distal epiphysis on the longitudinal axis of the freshly slaughtered bovine ribs. As a control, implants with the same sizes were inserted into the proximal diaphysis. The stability of the implants was examined with resonance frequency analysis.

Results

BLX and Tapered Effect implants showed higher implant stability quotient values in both study and control groups. All implant systems showed a significant decrease of mechanical anchorage in the study group. BLX and Bone Level Tapered designs had a significantly lower loss of mechanical anchorage in the lack of cortical bone.

Conclusion

Both Tapered Effect and BLX designs could ensure sufficient initial stability; however, BLX implants could be an appropriate option in the lack of cortical bone and poor bone quality at the implant recipient site.

Clinical relevance

BLX is a novel implant system, which could be especially beneficial in the presence of spongious bone type at posterior maxillae.

Retrospective study of alveolar ridge preservation compared with no alveolar ridge preservation in periodontally compromised extraction sockets

Background

To minimize alveolar bone resorption, alveolar ridge preservation (ARP) has been proposed. Recently, interest in improving the feasibility of implant placement has gradually increased, especially in situations of infection such as periodontal and/or endodontic lesions. The aim of this study was to investigate if ARP improves feasibility of implant placement compared with no ARP in periodontally compromised sites. Secondary endpoints were the necessity of bone graft at the time of implant placement and implant failure before loading at ARP compared with no ARP.

Material and methods

This retrospective study was performed using dental records and radiographs obtained from patients who underwent tooth extraction due to chronic periodontal pathology. Outcomes including the feasibility of implant placement, horizontal bone augmentation, vertical bone augmentation, sinus floor elevation, total bone augmentation at the time of implant placement, and implant failure before loading were investigated. Multivariable logistic regression analysis was performed to examine the influence of multiple variables on the clinical outcomes.

Results

In total, 418 extraction sites (171 without ARP and 247 with ARP) in 287 patients were included in this study. The ARP group (0.8%) shows significantly lower implant placement infeasibility than the no ARP group (4.7%). Horizontal and vertical bone augmentations were significantly influenced by location and no ARP. Total bone augmentation was significantly influenced by sex, location, and no ARP.

Conclusion

ARP in periodontally compromised sites may improve the feasibility of implant placement. In addition, ARP attenuate the severity of the bone augmentation procedure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-021-00305-2.