Jon B. Suzuki

Effect of Implant Design on Initial Stability of Tapered Implants

Implant design is one of the parameters for achieving successful primary stability. This study aims to examine the effect of a self-tapping blades implant design on initial stability in tapered implants. Polyurethane blocks of different densities were used to simulate different bone densities. The two different implant designs included one with self-tapping blades and one without self-tapping blades. Implants were placed at 3 different depths: apical third, middle third, and fully inserted at 3 different densities of polyurethane blocks. A resonance frequency (RF) analyzer was then used to measure stability of the implants. Repeated-measures analysis of variance was used to examine the effect of implant design, insertion depth, and block density on RF. Analysis of covariance was used to examine the strength of association between RF and the aforementioned factors. In both medium-density (P = .017) and high-density (P = .002) blocks, fully inserted non-self-tapping implants showed higher initial stability than self-tapping implants. No differences were noted between the 2 implant designs that were not fully inserted. The highest strength of association was with insertion depth (standardized beta [std beta] = -0.60, P = .0001), followed by block density (std beta = -0.15, P = .0002). Implant design showed a weak association (std beta = -0.07, P = .09). In conclusion, fully inserted implants without self-tapping blades have higher initial stability than implants with self-tapping blades. However, the association strength between implant design and initial stability is less relevant than other factors, such as insertion depth and block density. Thus, if bone quality and quantity are optimal, they may compensate for design inadequacy.

CTX biochemical marker of bone metabolism. Is it a reliable predictor of bisphosphonate-associated osteonecrosis of the jaws after surgery? Part II: a prospective clinical study.

Biochemical markers of bone metabolism have been used in medicine to evaluate and provide treatment to patients with metabolic bone diseases, such as osteoporosis. Serum cross-linked C-telopeptide of type I collagen (CTX) is a marker of osteoclast activity and is used to assess the level of bone resorption. Recently, in oral and maxillofacial surgery, it was proposed that the levels of serum CTX may predict the subsequent risk of developing osteonecrosis of the jaws (ONJ) after oral surgery procedures for patients taking oral bisphosphonates (BPs). The goal of this study was to determine whether this specific serum marker of bone resorption could preoperatively predict the risk of developing ONJ from oral BPs. We hypothesized that there is no clinical correlation between the observed preoperative serum CTX values and the risk of developing ONJ. The authors examine the scientific basis (validity) of the morning fasting serum CTX test in 163 consecutive patients who underwent various oral surgery procedures in the office. The authors also review the laboratory test results and the recommended protocol based on the test values. One hundred sixty-three patients (mean age, 75.9 years) were divided into 2 groups. Group I was the control group that consisted of 109 patients taking oral BPs who did not take the CTX test preoperatively. Group 2 consisted of 54 patients taking BPs and who elected to have the CTX test performed to assess their level of risk of developing ONJ, preoperatively. Both groups of patients were observed for a period of 8 weeks for signs and symptoms of BP-associated ONJ after surgery. The clinical data at 8 weeks and beyond revealed that there was no evidence of BP-associated ONJ in all participants. We conclude that the serum CTX is not a valid preoperative test to accurately assess the level of risk of developing ONJ and is not indicated in the oral surgery patient.

CTX biochemical marker of bone metabolism. Is it a reliable predictor of bisphosphonate-associated osteonecrosis of the jaws after surgery? Part I: biological concepts with a review of the literature.

Biochemical markers of bone metabolism have been used in medicine to evaluate and provide treatment to patients with metabolic bone diseases, such as osteoporosis. Serum cross-linked C-telopeptide of type I collagen is a marker of osteoclast activity and is used to assess the level of bone resorption. Recently, in oral and maxillofacial surgery, it was proposed that the levels of serum cross-linked C-telopeptide of type I collagen may predict the subsequent risk of developing osteonecrosis of the jaws after oral surgery procedures for patients taking oral bisphosphonates. The astute clinician must critically review the scientific literature and must decide if biochemical markers of bone resorption are of benefit in managing the oral surgery patient on bisphosphonates.

Identification and treatment of bisphosphonate-associated actinomycotic osteonecrosis of the jaws.

Osteonecrosis of the jaws (ONJ) is a condition characterized by necrotic exposed bone in the jaws of patients receiving intravenous or oral bisphosphonate therapy. A review of the medical and dental literature reveals that the pathoetiology of ONJ remains unknown and there is no established link that bisphosphonates are the primary cause of this bone pathology. However, there is clinical evidence that Actinomyces may play a critical role in the pathogenesis of bisphosphonate-associated ONJ. Identification and a prolonged course of oral antimicrobial therapy may lead to complete resolution of this actinomycotic osteonecrosis.

Use of cone beam computed tomography and a laser intraoral scanner in virtual dental implant surgery: part 1.

Objective:To describe a new procedure capable of coupling 2 data sets from cone beam computed tomography (CBCT) and an intraoral laser digital scanner to produce a stereolithographic model and surgical guide. Methods:Use of DICOM (digital imaging and communications in medicine) format data obtained from CBCT scan images merged with standard triangulation language (STL) file data obtained from digital impressions using an intraoral laser scanner. The 2 data sets were electronically sent to a 3-dimensional imaging and technology software company over the Internet to fabricate a stereolithographic model of the jaws and surgical guide without the use of stone or plaster models obtained from traditional dental impressions. Conclusion:STL file data are able to accurately fabricate a stereolithographic model and surgical guide for implant surgery.

Use of an Intraoral Laser Scanner During the Prosthetic Phase of Implant Dentistry: A Pilot Study

The accuracy of a digital impression technique to fabricate the implant restoration and abutment for a dental implant using an intraoral laser scanner was evaluated in 36 patients who were missing a single posterior tooth in either the mandible or maxilla that was restored with a single implant. The spatial position of each integrated implant, including the surrounding anatomic hard and soft tissues of adjacent structures, was captured utilizing a special scanning abutment with an intraoral laser scanner. Data from the scanning protocol was then delivered via the Internet in the form of an STL file to the manufacturing site for the production of a custom computer-aided design abutment and crown. All 36 restorations and abutments were delivered to the patients and evaluated for marginal integrity, interproximal contact points, and occlusion. Of the 36 patients, 6 required contact adjustments, 7 required occlusal adjustments, and 3 required a gingivectomy around the implant to completely seat the restoration. Chair time for adjustments did not exceed 15 minutes. The findings suggest that an intraoral laser scanner can be used with confidence to obtain consistent and accurate digital impressions to fabricate custom restorations and abutments for dental implants.

Sinus Grafting With a Natural Flourohydroxyapatite for Immediate Load: A Study With Histologic Analysis and Histomorphometry

The goal of this retrospective study was to evaluate the survival rates of dental implants placed in sinuses grafted with a 50:50 composite ratio of autogenous bone and a natural flourohydroxyapatite (FHA) combined with platelet-rich plasma (PRP) using an immediate-load protocol. The authors hypothesized that a 50:50 composite ratio of FHA and autogenous bone combined with PRP would permit immediate loading without compromising implant survival rates. Eleven patients with bilateral partial edentulism of the posterior maxilla were enrolled in this retrospective study. Autogenous bone used in the graft procedure was harvested from the tibia of the left lower extremity. Each patient was grafted with a 50:50 composite ratio of autogenous bone and FHA. Membranes were not used to cover the lateral wall osteotomy site. Platelet-rich plasma was added to the graft material to accelerate and enhance bone regeneration. Four to 6 months after the grafting procedure, 37 hydroxyapatite-coated dental implants were surgically placed and immediately loaded between 72 hours and 5 days later with custom titanium abutments and acrylic provisional restorations placed out of functional occlusion. Six months later, definitive ceramometal restorations were cemented on to the custom abutments. Patients were observed over a 52-week period. The overall implant survival rate was 97.3%. Histologic and histomorphometric analysis of core samples revealed formation of new vital bone in different graft specimens ranging from 23% to 34%. In each core bone sample, 100% of the bone sample was determined to be vital. In the grafted maxillary sinus, the natural FHA combined with autogenous bone in a 50:50 composite ratio with PRP is a suitable graft material permitting immediate load without compromising implant survival rates while decreasing the overall healing time.

A Survey of the Opinion and Experience of Uk Dentists: Part 1

Background:Dental implant-related iatrogenic trigeminal nerve (TG) injuries are proportionally increasing with dental implant surgery. This study, which is presented in greater detail over a series of articles, assessed the experience of implant-related TG nerve injuries among UK dentists. Incidence and cause of inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve (LN) injuries, together with preoperative assessment and the consent process, are presented in this article. Methods:A survey was distributed among 405 dentists attending an Association of Dental Implantology congress in the United Kingdom, of which 187 completed the survey. Results:Most responding dentists were full-time general practitioners. Implant dentistry training was predominately through industry-organized courses. Eighty dentists encountered implant-related IAN injuries, whereas 8 encountered LN injuries. Inaccurate radiological identification of the IAN/MN and their anatomical variations (48%) were seen to be the most frequent cause of TG injuries. Disclosure of the relative risk and benefits of alternative implant treatment strategies as part of the informed consent process was not deemed to be essential by 47 (25%) of the participants. Conclusion:Inadequate radiological assessment was the most common cause of TG nerve injury. The use of small field of view cone beam computer tomography (CBCT) is therefore recommended when placing implants in the posterior mandible. Implant surgeons should acquire evidence-based skills in the prevention, diagnosis, and management of TG nerve injury as well as specific training on justification and interpretation of CBCT scans.

A Survey of the Opinion and Experience of UK Dentists: Part 2: Risk Assessment Strategies and the Management of Iatrogenic Trigeminal Nerve Injuries Related to Dental Implant Surgery

Background: Dental implant–related iatrogenic injuries are proportionally increasing with dental implant surgery. This study assessed the experience of implant-related trigeminal nerve (TG) injuries among UK dentists. Risk management strategies and management of implant-related inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve injuries were investigated. Methods: A survey was distributed among 405 dentists attending an Association of Dental Implantology (ADI) congress, of which 187 completed the survey. Results: Most dentists (76% of 134 responses) allowed a 2 to 4 mm safety zone radiologically above the IAN when placing implants, and over half of the responders (56%) used implants that were 10 mm in length. The most frequent precautionary measure used by 73 (80%) responders was antibiotic coverage routinely to reduce the risk of infection when placing grafts in the posterior mandible. Other precautionary measures included unilateral staging of implant placement (57%), and 43% always identified the MN when placing implants. Nineteen dentists used steroids (eg, dexamethasone) routinely preoperatively and postoperatively. Twenty-six dentists used basic cone-beam CT (CBCT) minimally invasive techniques, and drill stops during implant placement were used by 14 responders. Although it is not highly recommended, steroids were used to manage the neuropathic pain and discomfort experienced by patients with IAN injuries in 40% of cases. Conclusion: Further training of dentists undertaking implant surgery is required so that they acquire up-to-date and evidence-based knowledge and skills in the prevention, diagnosis, and management of dental implant–related TG injuries. This training should also involve the justification and interpretation of CBCTs.

Prevalence of maxillary sinus pathology in patients considered for sinus augmentation procedures for dental implants.

Purpose:To determine the prevalence of maxillary sinus pathology in patients presenting for implant rehabilitation involving sinus augmentation procedures. Materials and Methods:Three-dimensional images of 275 patients were evaluated. Age and gender were recorded to see if they had any relationship to the prevalence of pathology. Scans were classified into 1 of the 5 categories based on the type of sinus pathology detected: healthy, mucosal thickening > 5mm, polypoidal mucosal thickening, partial opacification and/or air fluid level, and complete opacification. Results:Overall, 54.9% scans were classified as healthy, and 45.1% scans were classified as exhibiting sinus pathology. Men were more likely to exhibit pathology compared with females (P < 0.01). However, age did not seem to have any relation on the prevalence of sinus pathology. Of the patients who presented with evidence of sinus pathology, 56.5% had mucosal thickening (≥5mm), 28.2% with polypoidal thickening, 8.9% partial opacification and/or air/fluid level, and 6.5% complete opacification. Conclusions:It is proposed that, based on the findings of this study, 45.1% patients would require further consultation before proceeding with maxillary sinus augmentation surgery.