Preoperative radiologic planning of implant surgery in compromised patients

A Comparison of Different Implant Site Preparation Techniques in Low-Density Bone: An Ex-Vivo Study

INTRODUCTION

Osseointegration is considered a prerequisite for the long-term success of dental implants, and many researchers have considered the stability of the implant when placed in the bone. Many techniques include undersized drilling, densifying burs, magnetic mallets, and expanders. These methods have led to higher initial insertion torque values. The present study aims to evaluate the effectiveness of expanders, densifying burs, and magnetic mallet methods for preparing the implant site in low-density bone and compare them in terms of achieving good initial implant stability.

MATERIALS AND METHODS

The present study was conducted in an ex vivo animal model using bovine rib bones. This study was performed on 20 bovine ribs; each rib had four implant site preparations divided into four groups according to the drilling method: a control group of the conventional technique (n=20), the expanders group (n=20), the densification burs group (n=20), and the magnetic mallet group (n=20). The measured values were Primary Insertion Torque and Implant Stability Quotient (ISQ).

RESULTS

The highest average insertion torque was in the magnetic Mallet group, where the average was 43.75 N/cm2, followed by the burs group, where the average was 43.00 N/cm2, then the expanders group with an average of 32.80 N/cm2, then the conventional preparation group with 19.30 N/cm2 as the lowest average among the study groups. The highest ISQ mean was in the burs group, where the mean was 80.30, followed by the magnetic Mallet group, where the mean was 80.20, then the expanders group with a mean of 68.90, then the conventional preparation group with 50.10 as the lowest mean among the study groups.

CONCLUSION

Within the limitation of this study, we conclude that all methods used were better than conventional preparation in both ISQ and insertion torque, with the magnetic mallet group outperforming the insertion torque and the Densah burs outperforming the ISQ.

Surface Topography Has Less Influence on Peri-Implantitis than Patient Factors: A Comparative Clinical Study of Two Dental Implant Systems

OBJECTIVES

This study aims to assess the risk of peri-implantitis (PI) onset among different implant systems and evaluate the severity of the disease from a population of patients treated in a university clinic. Furthermore, this study intends to thoroughly examine the surface properties of the implant systems that have been identified and investigated.

MATERIAL AND METHODS

Data from a total of six hundred and 14 patients were extracted from the Institute of Clinical Dentistry, Dental Faculty, University of Oslo. Subject- and implant-based variables were collected, including the type of implant, date of implant installation, medical records, recall appointments up to 2022, periodontal measurements, information on diabetes, smoking status, sex, and age. The outcome of interest was the diagnosis of PI, defined as the occurrence of bleeding on probing (BoP), peri-implant probing depth (PD) ≥ 5 mm, and bone loss (BL). Data were analyzed using multivariate linear and logistic regression. Scanning electron microscopy, light laser profilometer, and X-ray photoelectron spectroscopy were utilized for surface and chemical analyses.

RESULTS

Among the patients evaluated, 6.8% were diagnosed with PI. A comparison was made between two different implant systems: Dentsply Sirona, OsseospeedTM and Straumann SLActive, with mean follow-up times of 3.84 years (SE: 0.15) and 3.34 years (SE: 0.15), respectively. The surfaces have different topographies and surface chemistry. However, no significant association was found between PI and implant surface/system, including no difference in the onset or severity of the disease. Nonetheless, plaque control was associated with an increased risk of developing PI, along with the gender of the patient. Furthermore, patients suffering from PI exhibited increased BL in the anterior region.

CONCLUSION

No differences were observed among the evaluated implant systems, although the surfaces have different topography and chemistry. Factors that affected the risk of developing PI were plaque index and male gender. The severity of BL in patients with PI was more pronounced in the anterior region. Consequently, our findings show that success in implantology is less contingent on selecting implant systems and more on a better understanding of patient-specific risk factors, as well as on implementing biomaterials that can more effectively debride dental implants.

Effect of metal artifact removal modes on the accuracy of linear measurement around titanium implants by applying different voltages: an original article

BACKGROUND

This study aims to evaluate the effects of the artifact removal algorithm on linear measurements of the buccal cortical plate by altering the voltage.

METHODS

Ten titanium fixtures were inserted at the site of central, lateral, canine, premolars and molars of dry human mandibles. Vertical height of buccal plate was measured using a digital caliper as a gold standard. Mandibles were scanned with 54 and 58 kVp. Other parameters were constant. Images were reconstructed with none, low, medium and high artifact removal modes. Two Oromaxillofacial radiologists evaluated and measured the buccal plate height using Romexis software. Statistical package for the social sciences (SPSS) version 24 was used for data analysis.

RESULTS

In medium and high modes, the difference between 54 and 58 kVp was significant (p < 0.001). No significance was noted by using low ARM (artifact removal mode) at the 54 kVp and 58 kVp.

CONCLUSION

Using artifact removal in low voltage decreases the accuracy of linear measurement and buccal crest visibility. By using high voltage, artifact removal would have no significant effect on accuracy of linear measurements.

Bone marrow stromal cells generate an osteoinductive microenvironment when cultured on titanium-aluminum-vanadium substrates with biomimetic multiscale surface roughness

Osseointegration of titanium-based implants possessing complex macroscale/microscale/mesoscale/nanoscale (multiscale) topographies support a direct and functional connection with native bone tissue by promoting recruitment, attachment and osteoblastic differentiation of bone marrow stromal cells (MSCs). Recent studies show that the MSCs on these surfaces produce factors, including bone morphogenetic protein 2 (BMP2) that can cause MSCs not on the surface to undergo osteoblast differentiation, suggesting they may produce an osteogenic environmentin vivo. This study examined if soluble factors produced by MSCs in contact with titanium-aluminum-vanadium (Ti6Al4V) implants possessing a complex multiscale biomimetic topography are able to induce osteogenesis ectopically. Ti6Al4V disks were grit-blasted and acid-etched to create surfaces possessing macroscale and microscale roughness (MM), micro/meso/nanoscale topography (MN), and macro/micro/meso/nanoscale topography (MMN^TM). Polyether-ether-ketone (PEEK) disks were also fabricated by machining to medical-grade specifications. Surface properties were assessed by scanning electron microscopy, contact angle, optical profilometry, and x-ray photoelectron spectroscopy. MSCs were cultured in growth media (GM). Proteins and local factors in their conditioned media (CM) were measured on days 4, 8, 10 and 14: osteocalcin, osteopontin, osteoprotegerin, BMP2, BMP4, and cytokines interleukins 6, 4 and 10 (IL6, IL4, and IL10). CM was collected from D14 MSCs on MMN^TMand tissue culture polystyrene (TCPS) and lyophilized. Gel capsules containing active demineralized bone matrix (DBM), heat-inactivated DBM (iDBM), and iDBM + MMN-GM were implanted bilaterally in the gastrocnemius of athymic nude mice (N= 8 capsules/group). Controls included iDBM + GM; iDBM + TCPS-CM from D5 to D10 MSCs; iDBM + MMN-CM from D5 to D10; and iDBM + rhBMP2 (R&D Systems) at a concentration similar to D5-D10 production of MSCs on MMN^TMsurfaces. Legs were harvested at 35D. Bone formation was assessed by micro computed tomography and histomorphometry (hematoxylin and eosin staining) with the histology scored according to ASTM 2529-13. DNA was greatest on PEEK at all time points; DNA was lowest on MN at early time points, but increased with time. Cells on PEEK exhibited small changes in differentiation with reduced production of BMP2. Osteoblast differentiation was greatest on the MN and MMN^TM, reflecting increased production of BMP2 and BMP4. Pro-regenerative cytokines IL4 and IL10 were increased on Ti-based surfaces; IL6 was reduced compared to PEEK. None of the media from TCPS cultures was osteoinductive. However, MMN-CM exhibited increased bone formation compared to iDBM and iDBM + rhBMP2. Furthermore, exogenous rhBMP2 alone, at the concentration found in MMN-CM collected from D5 to D10 cultures, failed to induce new bone, indicating that other factors in the CM play a critical role in that osteoinductive microenvironment. MSCs cultured on MMN^TMTi6Al4V surfaces differentiate and produce an increase in local factors, including BMP2, and the CM from these cultures can induce ectopic bone formation compared to control groups, indicating that the increased bone formation arises from the local response by MSCs to a biomimetic, multiscale surface topography.

Investigation on the application of digital guide templates guided dental implantation in China

BACKGROUND

The aim of this survey is to investigate the application of digital guide templates (DGTs) across China, and the views and attitudes of oral health professionals toward them.

METHODS

This survey was prepared, distributed, and collected by WJX. Chinese oral health professionals were invited to participate in it. The basic information of respondents, the application of DGTs, and the views and attitudes toward their status quo and development were statistically described. Chi-square test was used to evaluate the correlation between the basic information of respondents and the application of DGTs as well as the views and attitudes toward them.

RESULTS

A total of 276 questionnaires were collected, of which 273 were identified as valid. 269 (98.5%) respondents were dental clinical workers, 204 (74.7%) were dental clinical implant workers, and 152 (55.7%) had been engaged in the implant industry for more than five years. The chi-square test showed that working years were significantly correlated with the half-guided, tooth-supported, and mucosa-supported DGTs (P < 0.05); and professional backgrounds and working years presented significant differences in the views and attitudes toward the status quo and development of DGTs (P < 0.05). The questionnaires also made a preliminary investigation and evaluation on the factors influencing accuracy, indications, doctors' recommendations and relevant training.

CONCLUSION

Most respondents held a positive attitude toward the accuracy and development of DGTs. This survey can point out the direction for the improvement of DGTs, and provide a reference for the study of factors affecting implant accuracy, the establishment of a training system, and the understanding of clinicians' current views on DGTs. Trial registration This survey was approved by the Ethics Review Committee of Chenghuaxinguanghua Dental Clinic (Approval NO. CDCIRB-D-2021-201).

Does implant location influence the risk of peri-implantitis?

Peri-implantitis is characterized by nonreversible and progressive loss of supporting bone and is associated with bleeding and/or suppuration on probing. Peri-implant disease is considered as the main etiologic factor related to implant failure. Peri-implant disease has a pathogenesis similar to that of periodontal disease, both being triggered by an inflammatory response to the biofilm accumulation. Although the prevalence of peri-implantitis has been evaluated by several clinical studies with different follow-ups, there are currently little data on the impact of implant location and the prevalence of peri-implantitis. The aim of this review, therefore, was to summarize the evidence concerning the prevalence of peri-implantitis in relation to implant location and associated risk predictors. Even though most studies evaluating the prevalence of peri-implantitis in relation to implant location are cross-sectional or retrospective, they suggest that the occurrence of peri-implantitis is most prevalent in the anterior regions of the maxilla and mandible. Moreover, it seems that there is a higher prevalence of peri-implantitis in the maxilla than in the mandible.

Incidental Findings in Cone Beam Computed Tomography for Dental Implants in 1002 Patients

PURPOSE

The purpose of this study is to analyze the frequency and elevate the awareness of the prevalence of nondental pathology in cone beam computed tomography (CBCT) scans taken for implant placement treatment planning and postplacement evaluation. The data from the CBCT should be read by an oral and maxillofacial radiologist for proper diagnosis of dental and nondental pathology and referred to the medical specialist for proper management when necessary.

MATERIALS AND METHODS

This retrospective study analyzed 1002 consecutive CBCT scans taken at a single private practice noting the prevalence of nondental pathology in CBCT images for all dental implant procedures. All scans were taken from November 2007 to March 2020. One board certified oral and maxillofacial radiologist systemically read all scans and reported all findings in the maxilla and mandible, condyles and TMJ, paranasal sinuses, nasal fossa, pharyngeal airway, skull base and temporal bone, neck soft tissues, and cervical spine. The incidental findings, variation of normal anatomy, or pathology reported in these structures were categorized based on anatomic location and significance and the incidence was investigated.

RESULTS

Pathologies ranged from innocuous sinusitis, to more serious atherosclerotic calcification of the carotid arteries, narrowed airways, and neoplastic lesions. Fifty-one different findings were noted, of which 36 were pathologies that required referral or follow-up.

CONCLUSIONS

Incidental findings can be detected in CBCT scans for dental implants. The clinician must be familiar with the radiographic diagnosis of head and neck pathology, and/or must refer these images to an appropriate specialist for the radiographic interpretation of the full volume.

Guided implant surgery risks and their prevention

Ideal implant placement may reduce surgical complications, such as nerve injury and lingual cortical plate perforation, and minimize the likelihood of functional and prosthetic compromises. Guided implant surgery (GIS) has been used as the means to achieve ideal implant placement. GIS refers to the process of digital planning, custom-guide fabrication, and implant placement using the custom guide and an implant system-specific guided surgery kit. GIS includes numerous additional steps beyond the initial prosthetic diagnosis, treatment planning, and fabrication of surgical guide. Substantial errors can occur at each of these individual steps and can accumulate, significantly impacting the final accuracy of the process with potentially disastrous deviations from proper implant placement. Pertinent overall strategies to reduce or eliminate these risks can be summarized as follows: complete understanding of the possible risks is fundamental; knowledge of the systems and tools used is essential; consistent verification of both diagnostic and surgical procedures after each step is crucial; proper training and surgical experience are critical. This review article summarizes information on the accuracy and efficacy of GIS, provides insight on the potential risks and problems associated with each procedural step, and offers clinically relevant recommendations to minimize or eliminate these risks.

Does the Drilling Technique for Implant Site Preparation Enhance Implant Success in Low-Density Bone? A Systematic Review

PURPOSE

The objective of this systematic review was to investigate the possible association between the drilling technique and proper implant integration and survival in areas with low bone density.

MATERIALS AND METHODS

An electronic search using the MEDLINE/PubMed database was performed including studies published up to April 2018. Animal and clinical studies that evaluated the association between the drilling technique and proper implant integration and survival in low-density bone were included.

RESULTS

Fifteen studies met the inclusion criteria, including 7 experimental and 8 clinical. Undersized, osteotome, Piezosurgery, and osseodensification drilling were the 4 techniques found in the literature to enhance osseointegration of implants in low-density bone. Owing to the methodological variation, meta-analysis was not performed. The 4 drilling protocols were effective in increasing primary stability, but the long-term outcome is comparable with that of the conventional surgical drilling protocol.

CONCLUSION

There is weak evidence suggesting that any of the previously mentioned surgical techniques could enhance successful osseointegration and survival of the implants placed in low-density bone.

Ibandronate Treatment Before and After Implant Insertion Impairs Osseointegration in Aged Rats with Ovariectomy Induced Osteoporosis

Excessive decreases in bone volume (BV) and bone mineral density (BMD) can lead to osteoporosis, potentially hindering implant osseointegration. Bisphosphonates are commonly used to combat osteoporosis by slowing osteoclast-mediated resorption; however, functional osteoclasts are integral to bone remodeling and, thus, implant osseointegration, potentially contraindicating bisphosphonate use during implantation. To optimize the use of implant technologies in patients with compromised bone structure and metabolism, we need a more complete understanding of the biological response to surface design. The goal of this study was to assess the effects of osteoporosis and bisphosphonates on osseointegration of titanium (Ti) implants with microstructured surfaces, which have been shown to support osteoblast differentiation in vitro and rapid osseointegration in vivo. Forty, 8-month-old, virgin, female CD Sprague Dawley rats underwent ovariectomy (OVX) or sham (SHOVX) surgery. After 5 weeks, animals were injected subcutaneously with either the bisphosphonate (BIS), Ibandronate (25 µg/kg), or phosphate-buffered saline (PBS) every 25 days. 1 week after the initial injection, Ø2.5mm × 3.5mm microrough (SLA; grit-blasted/acid etched) implants were placed transcortically in the distal metaphysis of each femur resulting in four groups: 1) SHOVX+PBS; 2) SHOVX+BIS; 3) OVX+PBS; and 4) OVX+BIS. After 28d, qualitative properties of the bone and implant osseointegration were assessed using micro-computed tomography (microCT), calcified histomorphometry (Van Gieson's stain), and removal torque testing. microCT revealed decreased bone volume in OVX rats, which was slowed by bisphosphonate treatment. Reduced bone-to-implant contact (BIC) was evident in OVX+PBS compared to SHOVX+PBS. Although BV/TV was increased in OVX+BIS compared to OVX+PBS, bisphosphonate treatment had no effect on BIC. Removal torque testing revealed a higher maximum torque, torsional stiffness, and torsional energy in SHOVX compared to OVX with no effects due to bisphosphonate treatment. Our results show that osseointegration is decreased in osteoporotic animals. Ibandronate halts the progression of osteoporosis but does not enhance osseointegration. © 2019 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Evaluation of Extraction Site Dimensions and Density Using Computed Tomography Treated With Different Graft Materials: A Preliminary Study

PURPOSE

The preliminary human study was designed to evaluate extraction site changes using CT after socket preservation (SP) with different materials.

MATERIALS AND METHODS

Fifty-two sockets from 17 Turkish individuals (8 women and 9 men; mean age 44.70 ± 9.99 years) localized at the maxillary anterior area were treated with demineralized bone matrix + collagen membrane (CM) (N = 14), hydroxyapatite bone substitute (HBS) + CM (N = 14), CM (N = 13), or left empty (N = 11). CT scans were taken 10 and 120 days after the procedure. Horizontal and vertical socket dimensions and Hounsfield unit (HU) values were evaluated.

RESULTS

First 3 groups showed a significant horizontal decrease from day 10 to 120. No significant change was detected in vertical socket dimension. For both horizontal and vertical, no intergroup difference was detected at days 10 and 120. At days 10 and 120, HU values in HBS + CM group were significantly higher compared with others. Apical and coronal HU values were not different at any period.

CONCLUSION

Even if it did not provide better socket dimensions, HBS + CM treatment brought higher tissue density and thus, can be recommended to increase the bone quality and implant success after SP in upper anterior area.

Simple 3,4-Dihydroxy-L-Phenylalanine Surface Modification Enhances Titanium Implant Osseointegration in Ovariectomized Rats

Osteoporosis presents a challenge to the long-term success of osseointegration of endosseous implants. The bio-inspired 3,4-dihydroxy-L-phenylalanine (Dopa) coating is widely used as a basic layer to bind osteogenetic molecules that may improve osseointegration. To date, little attention has focused on application of Dopa alone or binding inhibitors of bone resorption in osteoporosis. Local use of a bisphosphonate such as zoledronic acid (ZA), an inhibitor of osteoclast-mediated bone resorption, has been proven to improve implant osseointegration. In this study, ovariectomized rats were divided into four groups and implanted with implants with different surface modifications: sandblasted and acid-etched (SLA), SLA modified with Dopa (SLA-Dopa), SLA modified with ZA (SLA-ZA), and SLA modified with Dopa and ZA (SLA-Dopa + ZA). Measurement of removal torque, micro-computed tomography and histology revealed a greater extent of bone formation around the three surface-modified implants than SLA-controls. No synergistic effect was observed for combined Dopa + ZA coating. Microarray analysis showed the Dopa coating inhibited expression of genes associated with osteoclast differentiation, similarly to the mechanism of action of ZA. Simple Dopa modification resulted in a similar improvement in osseointegration compared to ZA. Thus, our data suggest simple Dopa coating is promising strategy to promote osseointegration of implants in patients with osteoporosis.

A stepwise under-prepared osteotomy technique improves primary stability in shallow-placed implants: a preliminary study for simultaneous vertical ridge augmentation

Simultaneous vertical ridge augmentation (VRA) can reduce treatment procedures and surgery time, but the concomitant reduction in primary stability (PS) of a shallow-placed implant imparts risk to its prognosis. Although several studies have reported improvements in PS, there is little information from any simultaneous VRA model. This study aimed to evaluate whether tapered implants with stepwise under-prepared osteotomy could improve the PS of shallow-placed implants in an in vitro model of simultaneous VRA. Tapered implants (Straumann^® Bone Level Tapered implant; BLT) and hybrid implants (Straumann^® Bone Level implant; BL) were investigated in this study. A total of 80 osteotomies of different depths (4, 6, 8, 10 mm) were created in rigid polyurethane foam blocks, and each BLT and BL was inserted by either standard (BLT-S, BL-S) or a stepwise under-prepared (BLT-U, BL-U) osteotomy protocol. The PS was evaluated by measuring maximum insertion torque (IT), implant stability quotient (ISQ), and removal torque (RT). The significance level was set at P < 0.05. There were no significant differences in IT, ISQ or RT when comparing BLT-S and BL-S or BLT-U and BL-U at placement depths of 6 and 8 mm. When comparison was made between osteotomy protocols, IT was significantly greater in BLT-U than in BLT-S at all placement depths. A stepwise under-prepared osteotomy protocol improves initial stability of a tapered implant even in a shallow-placed implant model. BLT-U could be a useful protocol for simultaneous VRA.

[Accuracy of computer-guided implant placement and influencing factors]

Digital technology is a new trend in implant dentistry and oral medical technology. Stereolithographic surgical guides, which are computer-guided implant placement, have been introduced gradually to the market. Surgeons are attracted to this approach because of it features visualized preoperative planning, simple surgical procedure, flapless implant, and immediate restoration. However, surgeons are concerned about the accuracy and complications of this approach. This review aims to introduce the classification of computer-guided implant placement. The advantages, disadvantages, and accuracy of this approach are also analyzed. Moreover, factors that may affect the outcomes of computer-guided implant placement are determined. Results will provide a reference to surgeons regarding the clinical application of this approach.

Effect of Ratio of Residual Alveolar Bone to Graft Material in Contact With Fixture Surface on Marginal Bone Loss of Implants in Augmented Maxillary Sinuses: A 1-Year Retrospective Study

PURPOSE

The purpose of this retrospective study was to evaluate the influences of height or area ratio of residual alveolar bone to graft material on marginal bone loss around implants in the augmented maxillary sinuses with delayed implant placement.

MATERIALS AND METHODS

In this study, 42 patients with Astra implants in sinuses that had been augmented with alloplasts and allografts or xenografts (alveolar bone height ≤ 5 mm) were selected. Marginal bone level surrounding 1 implant per sinus was assessed by radiographic imaging at the time of final restoration delivery and 12 months after functional loading. To evaluate the marginal bone level alterations using clinical and radiographic data, Pearson's correlation analysis and Mann-Whitney test were performed.

RESULTS

Forty-six implants were included in this study. The residual bone/implant length ratio and the residual bone/implant area ratio were not associated with marginal bone loss at 1 year after functional loading (P > 0.05). And, marginal bone loss did not differ significantly between 2 types of graft materials during the observation period (P > 0.05).

CONCLUSION

The residual bone/implant length ratio and residual bone/implant area ratio were not associated with marginal bone loss around implants placed in augmented sinuses during 1 year of functional loading.

The Relevance of the Use of Radiographic Planning in Order to Avoid Complications in Mandibular Implantology: A Retrospective Study

The aim of this retrospective radiological study was to evaluate the variability of the mandibular anatomy in the presence and absence of teeth and to consider how it could influence implant planning. 187 mandibular CT DentaScans were selected from our department archive according to the inclusion criteria. The axial height, vertical height, angulation of the bone crest, and the bone available for ideal implant placement were measured. The analysis of the data shows that the mandible contour presents a constant degree of angulation. The variation of angulation in the absence of teeth was statistically significant only in the region between the canine and the first premolar and in that between the second premolar and the first molar. The difference between the crest height and the available distance to place the implant was greater in the region of the second molar while in the other regions the implant planning was made complex by postextraction resorption. Alveolar bone resorption after tooth loss can be considered as a risk factor for lingual cortical perforation during the insertion of an implant. To avoid potential intra/postoperative complications, 3D radiographic examination is recommended in order to study the mandibular anatomy and identify the risk areas.

CBCT-based bone quality assessment: are Hounsfield units applicable?

CBCT is a widely applied imaging modality in dentistry. It enables the visualization of high-contrast structures of the oral region (bone, teeth, air cavities) at a high resolution. CBCT is now commonly used for the assessment of bone quality, primarily for pre-operative implant planning. Traditionally, bone quality parameters and classifications were primarily based on bone density, which could be estimated through the use of Hounsfield units derived from multidetector CT (MDCT) data sets. However, there are crucial differences between MDCT and CBCT, which complicates the use of quantitative gray values (GVs) for the latter. From experimental as well as clinical research, it can be seen that great variability of GVs can exist on CBCT images owing to various reasons that are inherently associated with this technique (i.e. the limited field size, relatively high amount of scattered radiation and limitations of currently applied reconstruction algorithms). Although attempts have been made to correct for GV variability, it can be postulated that the quantitative use of GVs in CBCT should be generally avoided at this time. In addition, recent research and clinical findings have shifted the paradigm of bone quality from a density-based analysis to a structural evaluation of the bone. The ever-improving image quality of CBCT allows it to display trabecular bone patterns, indicating that it may be possible to apply structural analysis methods that are commonly used in micro-CT and histology.

Intraoperative Measurement of the Distance from the Bottom of Osteotomy to the Mandibular Canal Using a Novel Ultrasonic Device

BACKGROUND

In our previous study, we found that a novel ultrasound (US) device may serve as a useful intraoperative tool to measure the distance from osteotomy to the inferior alveolar canal (IAC).

PURPOSE

To validate our previous results in a larger group of osteotomies in the posterior mandible.

METHODS

During dental implant placement surgery, osteotomies were created using a standardized 2-mm-diameter pilot drill. The distance from the bottom of the osteotome to the IAC was assessed using an ultrasonic device and compared with a standard panoramic radiograph used to measure the same residual distance. The total distance from the crestal bone to the IAC was measured on a preoperative computed tomography (CT) and compared with total US measurements by summing the drill depth with residual depth measurements.

RESULTS

Mean radiographic and US residual distances were 5.19 ± 1.95 mm, 5.01 ± 1.82 mm, p = 0.79 respectively. These measurements presented strong positive correlations (r = 0.61, p = .01). Mean total CT distance was 13.48 ± 2.66 mm; mean total US calculation was 13.69 ± 2.51 mm. No significant difference was found (p > .05).

CONCLUSIONS

The results support our previous pilot study and confirm that the tested US device identifies the IAC and measures the distance from the osteotomy to the roof of the mandibular canal.

Impact of Bone Quality and Implant Type on the Primary Stability: An Experimental Study Using Bovine Bone

The purpose of this in vitro study was to compare the primary stability and removal torque of bone level and tissue level implants in different bone qualities. Twenty tissue level and bone level implants (3.3 × 10 mm and 4.1 × 10 mm) were used for assessing the stability in type II and type IV bone. Forty bovine rib blocks were used in this study. The primary stability of the implant was measured by the resonance frequency using an Osstel device. The removal torque values (RTV) of the implants was assessed using a digital torque gauge instrument. The implant stability quotient (ISQ) values and the RTV showed a marginally higher stability with bone level implants as compared to tissue level implants. However, these differences were not statistically significant in both type of bone used (P &gt; 0.05). On the other hand, compared to type IV, type II bone showed significant differences in the ISQ (P &lt; 0.01) and RTV (P &lt; 0.001) of bone level and tissue level implants. The study concluded that bone quality is an important factor in establishing primary stability than the implant dimension. Bone level and tissue level implants of same dimensions can be selected based on the esthetic demands since they showed similar mechanical properties.

Treatment of patients with tiolox-dentaurum dental implants at the polyclinic shoshi

INTRODUCTION

The importance of the dental implantology has influenced the development of many treatment methods in this field. The aim of our study is to evaluate the advantages and disadvantages of the treatment with TIOLOX-DENTAURUM dental implants in cases of partial and total lack of teeth, compared to classic dentures. To conduct our research we have used the prospective method.

MATERIAL AND METHODS

The analyzed cases have undergone surgical treatment at the "Policlinic Shoshi" in Prishtina during 2010-2011. This study included 29 patients, 23 in the research group and 6 in the control group. The patients involved in the study were 30-59 years old. 52,2% of our patients were 30-39 years old, while 17,4% were 50-59 years old.

RESULTS

In the research group, the average time of placing the dental bridges in the lower jaw was 2 months and 4.2 months in the control group. In the upper jaw, the average time was 3 months for the experimental group and 5,4 months for the control group.

CONCLUSION

The period after the placement of implants until the placement of dentures, can be shortened from 4-6 months to 3 months for the upper jaw and from 3 to 2 months for the lower jaw.

Role of primary stability for successful osseointegration of dental implants: Factors of influence and evaluation

A secure implant primary (mechanical) stability is positively associated with a successful implant integration and long-term successful clinical outcome. Therefore, it is essential to assess the initial stability at different time-points to ensure a successful osseointegration. The present study critically reviews the factors that may play a role in achieving a successful initial stability in dental implants. Databases were searched from 1983 up to and including October 2013 using different combinations of various keywords. Bone quality and quantity, implant geometry, and surgical technique adopted may significantly influence primary stability and overall success rate of dental implants.

Biological functionalization of dental implants with collagen and glycosaminoglycans-A comparative study

Biological implant surface coatings are an emerging technology to increase bone formation. Such an approach is of special interest in anatomical regions like the maxilla. In the present study, we hypothesized that the coating of titanium implants with components of the organic extracellular matrix increases bone formation and implant stability compared to an uncoated reference. The implants were coated using collagen-I with either two different concentrations of chondroitin sulfate (CS) or two differentially sulfated hyaluronans. Implant coatings were characterized biochemically and with atomic force microscopy. Histomorphometry was used to assess bone-implant contact (BIC) and bone-volume density (BVD) after 4 and 8 weeks of submerged healing in the maxilla of 20 minipigs. Further, implant stability was measured by resonance frequency analysis (RFA). Implants containing the lower CS concentration had significantly more BIC, compared to the uncoated reference at both times of interest. No significant increase was measured from week 4 to 8. Differences in BVD and RFA were statistically not significant. A higher concentration of CS and the application of sulfated hyaluronans showed no comparable increase in BIC. This study demonstrates a positive effect of a specific collagen-glycosaminoglycan combination on early bone formation in vivo.

Study of the osseointegration of dental implants placed with an adapted surgical technique

OBJECTIVE

To study the osseointegration of dental implants placed with a modified surgical technique in Beagle dogs and to compare it with the conventional method.

MATERIALS AND METHODS

Dental implants were placed bilaterally in the mandible of Beagle dogs using the press-fit as well as undersized implant bed preparation technique. Micro computer tomography (micro-CT) and histometric methods were used to analyze the bone implant contact and bone volume (BV) around the implants.

RESULTS

The bone-to-implant contact percentage (BIC: expressed as %), first BIC (1st BIC: expressed in mm), sulcus depth (SD: expressed in mm) and connective tissue thickness (CT: expressed in mm) were analyzed for both groups. The BIC percentage was significantly higher for the undersized installed implants (P=0.0118). Also, a significant difference existed between the undersized and press-fit installed implants for the first screw thread showing bone contact (P=0.0145). There were no significant differences in mucosal response (SD and CT) for both installation procedures. Also, no significant difference was found in the BV, as measured using micro-CT, between the implants placed with an undersized technique (59.3 ± 4.6) compared with the press-fit implants (56.6 ± 4.3).

CONCLUSION

From the observations of the study, it can be concluded that an undersized implant bed can enhance the implant-bone response.

Determination of the length of zygomatic implants through computed tomography: establishing a protocol

OBJECTIVES

The aim of this study was to establish and verify an examination protocol using CT to estimate the length of zygomatic implants, thus rendering the surgical process safer and more predictable, and exposing the patient to a minimal level of radiation.

METHODS

Paracoronal CT scan was carried out on ten dry human crania (n = 20) and the zygomatic implant sites were measured (L(CT)) bilaterally. A standard surgical zygomatic implant placement procedure was carried out and the actual lengths (L(Real)) and clinical lengths (L(Clin)) determined.

RESULTS

The averages of the L(CT), L(Clin) and L(Real) were 45.73 +/- 4.82 mm, 42.63 +/- 4.33 mm, and 44.73 +/- 4.53 mm, respectively. Student's t-test revealed no statistically significant differences between the L(Real) and L(CT) averages (P = 0.1532), whereas the L(Real) and L(Clin) averages were statistically different (P < 0.0001).

CONCLUSIONS

The proposed protocol proved to be precise and efficacious in the determination of zygomatic implant length, with the advantage to the patient of a relatively low level of exposure to radiation due to the small quantity of tomographic slices used. Although there were no major repercussions, the clinical probe in the zygomatic implant kit commonly used in this surgical procedure proved to be a rather imprecise tool.

Computer-assisted implantology: historical background and potential outcomes-a review

BACKGROUND

The accurate transfer of preoperatively determined implant positions to the patient mouth is very beneficial to the dental practitioner as well as patients. The objective of this paper was to review the gradual development of computer-assisted implant surgery.

METHODS

All of the major data sources including unpublished data in the internet are considered

RESULTS AND CONCLUSIONS

Computer-assisted/-guided/-aided implantology has been founded to overcome the errors encountered during implant osteotomies and to position the implants more precisely. The protocols followed by this sophisticated technique are based upon the advocated concept of prosthetic-driven implantology and CT-scan analysis recently approved. Although several attempts have been made to improve this approach more and more, little has been done regarding the patient's demands, including cost. The inherent complexity of the techniques and materials utilized necessitates several degrees of training before attempting treatment and must be taken into account.

Impact of local and systemic factors on the incidence of late oral implant loss

BACKGROUND

This retrospective study was set to assess the influence of systemic and local bone and intra-oral factors on the occurrence of implant loss from abutment connection up to 2 years.

MATERIALS AND METHODS

The files of 700 patients, have been collected randomly from the total patient group treated by means of endosseous Brånemark system implants (Nobel Biocare, Gothenburg, Sweden) at the Department of Periodontology of the University Hospital of the Catholic University of Leuven. The end point observation was evaluating the loss of the implants 2 years after abutment installation. The study involved all implants that did not encounter early loss and implants for which it was possible to evaluate its status 2 years after abutment surgery. Thus, data of 412 patients (240 females) provided with 1514 implants were analyzed. For each patient, the medical history was carefully checked. Data collection and analysis were mainly focused on endogenous factors such as hypertension, coagulation problems, osteoporosis, hypo- hyperthyroidism, chemotherapy, diabetes type I or II, Crohn's disease, some local factors [e.g. bone quality and quantity, implant (length, diameter, location), type of edentulism, PTV, radiotherapy], smoking habits, and breach of sterility during surgery.

RESULTS

Radiotherapy, implant (diameter and location), and higher PTV at implant insertion and abutment connection, all affected significantly the implant loss.

CONCLUSION

Implant location in the oral cavity and radiotherapy seem predominant to explain the occurrence of implant loss. On the other hand, smoking and systemic health factors do not seem to be prominent players in the etiology of late implant loss.

Comparative localized linear accuracy of small-field cone-beam CT and multislice CT for alveolar bone measurements

OBJECTIVES

To compare the accuracy of cone-beam computerized tomography (CBCT) and multislice CT (MSCT) for linear jaw bone measurements.

STUDY DESIGN

An ex vivo formalin-fixed human maxilla was imaged with both CBCT (Accuitomo 3D; Morita, Kyoto, Japan) and MSCT (4-slice Somatom VolumeZoom and 16-slice Somatom Sensation 16; Siemens, Erlangen, Germany). The MSCT images were reconstructed using different reconstruction filters to optimize bone visualization (U70u and U90u for VolumeZoom, H30s and H60s for Sensation 16). Before scanning, triplets of small gutta-percha markers were glued onto the soft tissues overlying the maxillary bone on the top and on both sides of the alveolar ridge to define a set of reproducible linear measurements in 11 planes. Image measurements were performed by 2 observers. The gold standard was determined by means of physical measurements with a caliper by 3 observers.

RESULTS

The accuracy of the linear measurements was 0.35 +/- 1.31 mm (U70u) and 0.06 +/- 1.23 mm (U90u) for the Somatom VolumeZoom, 0.24 +/- 1.20 mm (H60s) and 0.54 +/- 1.14 mm (H30s) for the Sensation 16, and -0.09 +/- 1.64 mm for the Accuitomo 3D. Statistical analysis with 2-way analysis of variance showed no significant inter- or intraobserver disagreement for the physical or the radiologic measurements. There was also no significant difference for the measurements on the different reconstruction filters.

CONCLUSION

Both CBCT and MSCT yield submillimeter accuracy for linear measurements on an ex vivo specimen.

A biomechanical assessment of the relation between the oral implant stability at insertion and subjective bone quality assessment

AIM

The study was set to evaluate the validity of subjective jaw bone quality assessment.

MATERIALS AND METHODS

A total of 298 patients (198 females, mean age 56.4) were treated with oral implants at the Periodontology Department at the University Hospital of KUL. A total of 761 TiUnite implants have been installed. Subjective bone quality assessment was performed on radiographs and by the surgeon's tactile sensation and was compared with torque measurements. In a subset of patients, implant stability was also assessed by implant stability quotient and/or periotest values.

RESULTS

Subjective assessment of bone quality was related to the PTV, ISQ and placement torque [in the crestal, the second and the apical third (N cm)], respectively; in grade 1: -5.3, 73.3 (4.2, 9.6, 15.2), and grade 3 or 4: -1.6, 55 (3.3, 5.5, 8.4). For the surgeon's tactile sensation, a good correlation was noted for the presence of a thick cortex: -4.6, 70.3 (4.2, 9.7, 15.1), or a thin one: -0.3, 65.9 (3.6, 6.9, 10.1). For dense trabecular bone, the values were -2.8, 69.4 (4.4, 9.7,14.8), while for poor trabecular bone, the values were-1.7, 66.4 (3.6, 6.4, 9.8).

CONCLUSIONS

Subjective assessment of bone quality is related to PTV, ISQ and placement torque measurements at implant insertion.

Adapted preparation technique for screw-type implants: explorative in vitro pilot study in a porcine bone model

OBJECTIVE

The aim of this study was to quantify the effect of adapted preparation on the insertion torque of self-tapping implants in cancellous bone. In adapted preparation, bone condensation - and thus, insertion torque - is controlled by changing the diameter of the drilling.

MATERIAL AND METHODS

After preparation of cancellous porcine vertebral bone with drills of 2.85, 3, 3.15 or 3.35 mm final diameters, Brånemark sytem Mk III implants (3.75 x 11.5 mm) were inserted in 141 sites. During implantation, the insertion torque was recorded. Prior to implant insertion, bone mineralization (bone mineral density (BMD)) was measured with dental quantative computed tomography. The BMD values measured at the implant position were correlated with insertion torque for varying bone condensation.

RESULTS

Based on the average torque recorded during implant insertion into the pre-drilled canals with a diameter of 3 mm, torque increased by approximately 17% on reducing the diameter of the drill by 5% (to 2.85 mm). On increasing the diameter of the osteotomy to 3.15 mm (5%) or 3.35 mm (12%), torque values decreased by approximately 21% and 50%, respectively.

CONCLUSION

The results demonstrate a correlation between primary stability (average insertion torque) and the diameter of the implant bed on using a screw-shaped implant. Thus, using an individualized bone mineralization-dependent drilling technique, optimized torque values could be achieved in all tested bone qualities with BMDs ranging from 330 to 500 mg/cm(3). The results indicate that using a bone-dependent drilling technique, higher torque values can also be achieved in poor bone using an individualized drilling resulting in higher bone condensation. As immediate function is dependent on primary stability (high insertion torque), this indicates that primary stability can be increased using a modified drilling technique in lesser mineralized bone.

Influence of cortical bone thickness and implant length on implant stability at the time of surgery--clinical, prospective, biomechanical, and imaging study

This clinical study is the first to quantitatively evaluate both regional bone structure by computed tomography preoperatively and dental implant stability by resonance frequency analysis at the time of surgery to explore the relation between local bone structure and dental implant stability in humans. Implant stability at the time of installation is often difficult to achieve in lower density bone and implant stability might influence treatment efficacy. Few clinical studies have reported detailed bone characteristics obtained using computed tomography prior to surgery and comprehensive implant stability measurements at the time of surgery. We hypothesized that thicker cortical bone would improve the stability of the dental implant at the time of placement. Before radiographic examination, diagnostic radiographic templates were made by incorporating radiopaque indicators. Computed tomography scans were obtained for 50 edentulous subjects prior to surgery. Preoperatively, the thickness of the cortical bone at the sites of implant insertion was measured digitally, and then implant insertion surgery was performed. A total of 225-implant stability measurements were made using a resonance frequency analyzer. There was a strong linear correlation between cortical bone thickness and resonance frequency (r = 0.84, P < 0.0001). The implant length had a weak negative correlation with stability (r = -0.25, P < 0.0005). These results suggest that the initial stability at the time of implant installation is influenced more by cortical bone thickness than by implant length. The cortical and cancellous ratio of local bone is extremely important for implant stability at the time of surgery and determining the local bone condition is critical for treatment success.