Leadership education in prosthodontics: Development and impact of the Future Leaders in Prosthodontics (FLIP) workshops.

STATEMENT OF PROBLEM: The effectiveness of leadership education for prosthodontists is unknown. PURPOSE: The purpose of this survey study was to evaluate the self-perceived impact a 2- to 2.5-day leadership education workshop in prosthodontics had on participants' professional, leadership, and management development. MATERIAL AND METHODS: Participants who attended a leadership workshop for future leaders in prosthodontics (FLIP) were surveyed to assess their self-reported improvements in different leadership domains. The survey was administered to 89 participants using an online survey tool, and demographic data about participants were also collected. Results were tabulated for descriptive presentation. Where applicable, the Spearman correlation coefficients were calculated. RESULTS: Seventy-two individuals responded to the invitation for a response rate of 80.9%. Improvement in all 11 leadership capabilities assessed in the survey was noted by over 75% of respondents. Over 90% of respondents reported improvement in overall leadership, career management, team management, self-awareness, problem-solving, and conflict resolution. No significant (P>.13) relationships were found among demographic data such as age, sex, home continent, or primary career focus (academics or private practice). CONCLUSIONS: Within the limitations of this survey study, participants in a leadership workshop noted improvement in a variety of leadership capabilities.

Males With Rheumatoid Arthritis Often Evidence Carotid Atheromas on Panoramic Imaging: A Risk Indicator of Future Cardiovascular Events.

PURPOSE: Males with rheumatoid arthritis (RA) are at an exceedingly high risk of adverse intraoperative ischemic events, given the role of systemic inflammation in the atherogenic process. We hypothesized that their panoramic images would demonstrate calcified carotid artery atheromas (CCAPs) significantly more often than those from a general population of similarly aged men. PATIENTS AND METHODS: We implemented a retrospective observational study. The sample was composed of male patients older than 55 years of age who had undergone panoramic imaging studies. The predictor variable was the diagnosis of RA confirmed by a positive rheumatoid factor (RF) titer, and the outcome variable was the prevalence rate of CCAPs. The other major study variable was the level of RF among the patients evidencing CCAPs. The prevalence of CCAPs among the patients with RA was then compared with that of a historical general population of similarly aged men. Descriptive and bivariate statistics were computed, and the P value was set at .05. RESULTS: Of the 100 men (mean age 69.89 ± 8.927 years) with RA, 29 (29%; mean age 72.10 ± 7.68 years) had atheromas (CCAP+). Of these 29 men, 25 (86%; mean age 71.88 ± 7.43 years) had a RF titer of ≥41 IU/mL, twice that of normal. A statistically significant (P < .05) association was found between a diagnosis of RA and the presence of an atheroma on the panoramic image compared with the 3% rate found in the historical cohort. CONCLUSIONS: The results of the present study suggest that CCAP, a risk indicator of future adverse cardiovascular events, is frequently seen on panoramic images of male patients with RA and that these individuals routinely manifest high titer levels of RF, a biologic marker of inflammation. Oral and maxillofacial surgeons planning surgery for male patients with RA must be uniquely vigilant for the presence of these lesions.

Prevalence of calcified carotid artery atheromas on digital panoramic images among perimenopausal and postmenopausal African American women.

OBJECTIVE: Health care disparities, often of an obscure nature, result in African American women (AAw) having enhanced risk of adverse cardiovascular events. Therefore, we sought to determine the prevalence of calcified carotid artery atheromas (CCAA), a validated risk indicator of these events, on their digital panoramic images. STUDY DESIGN: Comprehensive electronic medical records and digital panoramic images of self-identified AAw aged ≥45 years treated between 2007 and 2014 were retrieved from a Veterans Affairs Dental Service. Images were reviewed for CCAA in the cervical bifurcation region, and medical records were reviewed for atherogenic risk factors: hypertension, diabetes, and dyslipidemia. RESULTS: The study sample of 171 AAw (mean age 58.2 ± 8.0 years) evidenced a 24% CCAA positive prevalence rate. In comparison with the CCAA negative group, those with atheromas were significantly older (61.4 ± 10.1 vs. 57.2 ± 7.0), diabetic, and dyslipidemic. Also observed among the full study sample was significant concordant increase of CCAA prevalence with age. Among those who were CCAA positive, there was a significant increased prevalence of dyslipidemia with age. CONCLUSIONS: Panoramic images of older AAw frequently revealed carotid atheromas, a risk indicator of generalized atherosclerosis and future adverse cardiovascular events.

Patients Receiving Parenteral Bisphosphonates for Malignant Disease and Having Developed an Atypical Femoral Fracture Are at Risk of Concomitant Osteonecrosis of the Jaw: An Evidence-Based Review.

PURPOSE: The risk of developing concomitant medication-related osteonecrosis of the jaw (MRONJ) in patients who have sustained an atypical femoral fracture (AFF) in association with parental administration of a bisphosphonate osteoclastic inhibitor medication for malignant disease is unclear. Published data were searched to determine the prevalence of these concomitant adverse medication events, if any. MATERIALS AND METHODS: A systematic review of published case series in the PubMed database was undertaken to ascertain the prevalence of patients having a concomitant history of AFF and MRONJ. The data were analyzed to provide prevalence rates of these events from the literature. RESULTS: Two case series were identified that delineated the risk (25 and 33%, respectively) of concomitant development of MRONJ and AFF in recipients of parenteral bisphosphonate medication administered for malignant disease. CONCLUSION: The published data suggest that approximately 30% of patients receiving parenteral bisphosphonates and having sustained an AFF could develop comorbid MRONJ.

Meaningful correlation between asymptomatic retinal arteriole emboli and calcified carotid plaque found on panoramic dental imaging of males with diabetes.

OBJECTIVE: There is ongoing controversy with regard to the stability of calcified carotid artery plaques (CCAPs) seen in the bifurcation area on panoramic images (PIs). Therefore, we sought to evaluate the possibility of these plaques shedding emboli by observing their relationship with ipsilateral retinal emboli. STUDY DESIGN: The study group included 50 neurologically and visually asymptomatic males with diabetes, with PIs that incidentally demonstrated CCAPs (CCAP+) and contemporaneous digital retinal images that had been obtained for evaluation of diabetic retinopathy. The control group consisted of 50 males with diabetes who were matched for age and body mass index and had undergone both imaging studies and whose PIs were devoid of carotid plaques (CCAP-). The presence of retinal emboli was determined by two ophthalmologists blinded to the patients' medical histories, and the prevalence rates for the two groups were calculated. RESULTS: The presence of asymptomatic retinal arteriolar emboli was found in the eye ipsilateral to the radiographically observed carotid atheroma in 10 of 50 (20%) of the patients in the CCAP+ group, compared with 2 of 50 (4%) in the CCAP- group, and this difference was statistically significant (Fisher's exact P < .03). CONCLUSIONS: Some male patients with diabetes mellitus type II having calcified carotid artery atheromas in the bifurcation area, as visualized on PIs, may have significant sequelae as evidenced by retinal artery emboli.

High C-Terminal Cross-Linking Telopeptide Levels Are Associated With a Minimal Risk of Osteonecrosis of the Jaws in Patients Taking Oral Bisphosphonates and Having Exodontia.

PURPOSE: The clinical significance of bone turnover marker C-terminal cross-linking telopeptide (CTX) levels less than 150 pg/mL among recipients of oral bisphosphonate (OBP) medications who develop osteonecrosis of the jaws (MRONJ) after exodontia is unclear. We searched the published data to determine the prevalence of such levels and the association, if any, with development of MRONJ. MATERIALS AND METHODS: A systematic review of published studies in the PubMed database was undertaken to ascertain the prevalence of preoperative, fasting CTX levels less than 150 pg/mL among recipients of OBP scheduled for exodontia and to determine whether such levels are associated with the development of postoperative MRONJ. The data were aggregated and analyzed to provide the sensitivity, specificity, and positive and negative predictive values of the association between low CTX levels and the development of MRONJ. RESULTS: Two studies were chosen for review. The first, with an enrollment of 21 patients, reported that 10 (48%) patients had a preoperative CTX level less than 150 pg/mL and that after exodontia, none developed MRONJ. The second study, with an enrollment of 950 patients, reported that approximately 282 (30%) had a preoperative CTX level less than 150 pg/mL. All the patients with depressed CTX levels were offered a "drug holiday"; however, only 101 accepted the offer. Of the remaining 181 patients, 4 developed MRONJ. The aggregated study data have demonstrated that 30% of patients evidence CTX levels less than 150 pg/mL and that the sensitivity and specificity of these levels in association with the development of MRONJ was 100% and 80.7%, respectively. The positive predictive value was 2.09% and the negative predictive value was 100%. CONCLUSION: The published data suggest that approximately one third of patients exposed to OBP will evidence depressed CTX levels and that only a very small minority (∼2%) will develop postexodontia MRONJ. Prudence would suggest that patients scheduled for exodontia and receiving OBPs should be informed about the strengths and weaknesses of the CTX test and that it should be offered during the consent process.

Association of calcified carotid atheromas visualized on panoramic images and aortic arch calcifications seen on chest radiographs of postmenopausal women.

BACKGROUND: Occult atherosclerotic disease is the leading cause of death among older women. The authors hypothesized that women with calcified carotid artery plaque (CCAP) visualized on panoramic images were more likely to have aortic arch calcifications (AAC) that were visible on chest radiographs (CRs), a risk indicator of experiencing cardiovascular events, than would matched cohorts who did not have atheromas. METHODS: The authors obtained the CRs of 36 female veterans (≥ 50 years) who had CCAP and atherogenically risk-matched them to those of 36 women without CCAP. A radiologist evaluated the CRs for AAC. Other study variables included age, ethnicity, body mass index and presence or absence of hypertension, diabetes and dyslipidemia. The authors computed descriptive and bivariate statistics. RESULTS: Women 60 years or older who had evidence of CCAP on their panoramic radiographs were significantly (P = .022; 95 percent confidence interval, 1.298-26.223) more likely to have evidence of AAC on their CRs than were similarly aged women who did not have evidence of CCAP. This association was not evident in women younger than 60 years. Among women who were both younger and older than 60 years, there was no evident association between the presence of CCAP and the severity (on a four point scale [0-3]) of AAC calcification. CONCLUSION: Prevalence of carotid plaque on panoramic images of women 60 years or older is significantly associated with presence of aortic arch calcifications on CRs. PRACTICAL IMPLICATIONS: Panoramic images of women 60 years or older must be evaluated for CCAP, given their association with AAC. Patients with atheromas should be referred to their physicians for further evaluation given the systemic implications.

Effect of implant support for prostheses on electromyographic activity of masseter muscle and jaw movement in patients after mandibular fibula free flap reconstruction.

PURPOSE: Dental implants are used to stabilize, support, and retain prostheses in the mandible following fibula free flap reconstruction. A previous longitudinal prospective study showed that an implant-supported prosthesis (IP) provided additional improvement in masticatory performance compared to a conventional prosthesis (CP). Therefore, in this paper, the impact of implant retention and support of mandibular prostheses on neuromuscular function is reported via a within-subject analysis. MATERIALS AND METHODS: Forty-six participants were enrolled in the study. Prosthetic treatment with a CP was completed in 33 subjects following oromandibular resection and fibula free flap reconstruction. Twenty-five subjects completed evaluation of the CP after an adaptation period. Standardized masticatory tests with peanuts were given to subjects on the defect and nondefect chewing sides. Electromyography (EMG) of masseter muscles and jaw movement was performed and recorded simultaneously in 19 of these subjects. IP treatment was then completed in 16 of these subjects, and 15 of them participated in the IP evaluation after an adaptation period. Of these 15 subjects, 13 completed EMG and jaw movement recordings for both CP and IP. RESULTS: EMG activity of the defect-side masseter muscle increased significantly from CP to IP conditions when chewing on either side, but no significant change was found for nondefect-side muscle activity. Jaw movement parameters showed no significant changes from CP to IP. CONCLUSION: In patients restored with mandibular fibula free flap reconstruction, implant support for mandibular prostheses has the benefit of permitting greater muscle effort on the defect side, irrespective of the side on which the bolus is being chewed. The impact of an IP on jaw movements is limited.

Functional outcomes for clinical evaluation of implant restorations.

The functional outcomes related to treating patients afflicted with tooth loss are an important hallmark in substantiating prosthodontic intervention. The Oral Rehabilitation Outcomes Network (ORONet) conducted two international workshops to develop a core set of outcome measures, including a functional domain. The process followed the general format used in the Outcome Measures in Rheumatology (OMERACT) workshops to develop consensus for clinical outcome measures in arthritis research, which included: developing a comprehensive list of potential outcomes in the literature; submitting them to a filter for validity, clinical discrimination, and feasibility; and ranking those measures meeting all the filter criteria for relative value. The search was conducted to include functional assessments of speech, swallowing, mastication, nutrition, sensation, and motor function as they relate to dental implant therapies. This literature review surveyed 173 papers that produced some result of these descriptors in the functional domain. Of these, 67 papers reported on functional assessments and further defined objective and subjective outcomes. Many of these results were patient-perceived improvements in function, while others were objective assessments based on established methodologies and instruments. Objective evaluations of masticatory function and speech may meet criteria for validity and discriminability for selected interventions, but are generally not feasible for routine use in clinical care settings. The current recommendation is to employ a well-validated survey instrument that covers mastication and speech, such as the Oral Health Impact Profile (OHIP-14, short form), recognizing that patient perceptions of function may differ from objective ability.

Psychologic outcomes in implant prosthodontics.

Consensus regarding outcomes of the treatment of tooth loss, especially the psychologic outcomes, is needed to guide discovery of best practices and enable a better understanding of patient management for this chronic condition. This paper presents the findings of the ORONet Psychological Working Group for prosthodontics and aims to identify psychologic outcomes with properties deemed critical to meet clinical trial and clinical practice needs for the future. References obtained using a PubMed/Medline search were reviewed for clinical outcomes measures of interest. Clinical outcomes measures were judged relative to the criteria of truth, discrimination, and feasibility. Of the psychologic outcome measures identified in this systematic review, only the OHIP-14 was thought to be suitable for use in general practice and multi-institutional outcome registries and clinical trials. Development of clinically useful psychologic outcomes for future use could benefit from developmental methods and tools outlined in the patient-related outcomes field of clinical care.

Economic outcomes in prosthodontics.

PURPOSE: A systematic literature review was conducted to identify the types of economic measures currently used in implant prosthodontics and determine the degree to which cost of care is considered in the context of any positive outcome of the care provided. MATERIALS AND METHODS: A literature search was conducted using the following set of terms plus some additional hand searching: "dental implants" (Mesh) AND ("cost") OR "maintenance" OR "healthcare policy" OR "access to care" OR "third party" OR "economic") AND (("1995/01/01"[PDat]:'2009/12/31"[PDat]) AND (Humans[Mesh]) AND (English[lang])). RESULTS: After a review of the 466 titles and abstracts identified by the search, 18 articles were accepted for further consideration, as some attempt at economic outcome measures was made. An additional four articles were identified by hand searching. The 22 accepted articles were grouped into four basic categories: (1) measure of costs of treatment (direct, indirect, and maintenance costs), (2) cost-effectiveness mathematical modeling applied to simulate the lifetime paths and cost of treatment, (3) cost-effectiveness analysis/cost minimization, and (4) willingness-to-pay, willingness-to-accept. Attempts at determining the costs of treatment varied widely. When the OMERACT filters were applied to the various measures it was felt that discrimination and/or feasibility was a problem for most of the current economic outcome measures. CONCLUSIONS: Measures of cost-benefit, cost-effectiveness, and cost-utility are currently the gold standard; however, feasibility of such analyses is an issue. Collaboration with health economists to guide future research is highly recommended.

Oral Rehabilitation Outcomes Network-ORONet.

The published literature describing clinical evidence used in treatment decisionmaking for the management of tooth loss continues to be characterized by a lack of consistent outcome measures reflecting not only clinical performance but also a range of patient concerns. Recognizing this problem, an international group of clinicians, educators, and scientists with a focus on prosthodontics formed the Oral Rehabilitation Outcomes Network (ORONet) to promote strategies for improving health based on comprehensive, patient-centered evaluations of comparative effectiveness of therapies for oral rehabilitation. An initial goal of ORONet is to identify outcome measures for prosthodontic therapies that represent multiple domains with patient relevance, are amenable to utilization in both institutional and practice-based environments, and have established validity. Following a model used in rheumatology, the group assessed the prosthodontic literature, with an emphasis on implantbased therapies, for outcomes related to longevity and functional, psychologic, and economic domains. These systematic reviews highlight a need for further development of standardized outcomes that can be integrated across clinical and research environments.

Clinical outcomes measures for assessment of longevity in the dental implant literature: ORONet approach.

The Oral Rehabilitation Outcomes Network (ORONet) Longevity Working Group undertook a search of the literature from 1995 to 2009 on randomized controlled trials related to longevity of osseointegrated implants. Outcomes measures used in these studies were identified and subjected to the OMERACT component criteria of truth, validity, and feasibility. Through this process, it was a challenge to identify clinical outcomes measures that fully met the criteria. An attenuated version of the component criteria was applied, and clinical measures were identified for implant outcomes, prosthetic outcomes, and indices. A recommendation on standardized reporting periods was also presented for future consideration. The endpoint of the evaluation process is to develop consensus on clinical outcomes measures that can be applied across broad populations for osseointegrated implant care. The present ORONet initiative represents a beginning toward continual improvement and consensus development for clinical outcomes measures for osseointegrated implants.

Do carotid atheromas on panoramic images prognosticate arterial calcifications on mammograms: acknowledged markers of future adverse cardiovascular events?

OBJECTIVE: The aim of this study was to evaluate the relationship between calcified carotid artery plaque (CCAP) on panoramic images and breast arterial calcifications (BAC) on mammograms, a validated independent risk indicator of fatal myocardial infarctions and strokes. MATERIALS AND METHODS: Women ≥55 years old having CCAP diagnosed by their dentists had their mammograms evaluated for BAC by a physician. Other study variables were age, ethnicity, body mass index, and medications for hypertension, diabetes, and dyslipidemia. Descriptive and bivariate statistics and logistic regression were computed. RESULTS: Researchers identified 40 women (mean age 62.2 ± 6.2 years old) with CCAP, of whom 9 (prevalence rate 22.5%) also had BAC. The women with BAC tended to be older (65.1 vs 61.3 years old), more frequently hypertensive (100% vs 80.6%), and more frequently black than those without BAC, although these differences were not statistically significant (P > 0.10). CONCLUSIONS: CCAP on panoramic images of women is unrelated to the presence of BAC on mammograms.

Resolution of pain and complete healing of mandibular osteoradionecrosis using pentoxifylline and tocopherol: a case report.

The radiation-induced fibroatrophic process (RIF) is a time-dependent adverse sequela to high-dose radiotherapy that can result in irreversible tissue death and bone exposure in the irradiated tissue. Osteoradionecrosis (ORN) is a late effect of RIF, described as bony exposure present for more than 3 months that can occur in 20% of patients irradiated for head and neck cancer. The intractable characteristics of ORN make both management and resolution of the disease process challenging, with 25% of cases recurring despite aggressive treatment with resection and reconstruction of the necrotic bone. In this article, we present a case of a 66-year-old man with unevoked ORN of the left posterior lingual mandibular cortex that was successfully treated and resolved with 6 months of pentoxifylline 400 mg twice a day and tocopherol 1000 IU every day.

Prevalence of calcified carotid artery atheromas on the panoramic images of patients with syndrome Z, coexisting obstructive sleep apnea, and metabolic syndrome.

OBJECTIVES: The objective of this study was to compare the prevalence of calcified carotid artery atheromas (CCAAs) on panoramic images of individuals (n = 31) with obstructive sleep apnea (OSA) with individuals (n = 117) with syndrome Z (SZ: OSA with concomitant metabolic syndrome [MetS]). STUDY DESIGN: Images of patients with OSA or SZ referred from the Sleep Service to Dentistry were evaluated. Descriptive statistics and t tests (Bonferroni correction) were conducted to determine significant differences between atheroma prevalence and proatherogenic factors (age, apnea-hypopnea index, body mass index, lipid profile, blood pressure, glucose) between OSA and SZ groups. RESULTS: Individuals with OSA had an atheroma prevalence of 35% and those with SZ 42% (P = .52). Individuals with SZ also had significantly more severe atherogenic profiles (obesity, dyslipidemia, hyperglycemia) than OSA patients (P ≤ .05). Greatest CCAA prevalence (63%) was evidenced by SZ patients with severe OSA and moderate MetS. CONCLUSION: Individuals with SZ have significantly greater atherogenic burden and slightly higher prevalence of CCAAs when compared with individuals with OSA.

Panoramic radiographs of head and neck cancer patients are often evidence of carotid artery atherosclerotic lesions: a sign of high-risk comorbid illness.

PURPOSE: The purpose of this study was to estimate the prevalence and identify the risk factors for calcified carotid artery plaque (CCAP) in patients with squamous cell carcinoma of the head and neck. MATERIALS AND METHODS: Radiographs of 48 consecutive patients were evaluated for CCAP and their medical histories reviewed for the anatomic extent of cancer (staging) and atherogenic risk factors (age, extent of alcohol and tobacco use, body mass index, hypertension, dyslipidemia, and diabetes mellitus). RESULTS: Unilateral or bilateral CCAPs were found in 52.1% of subjects (mean age, 61.5 years). Hypertension was seen in a larger percentage (60%; P = .049) of subjects with CCAP on their radiographs compared with those without CCAP (30.4%). No other atheroma risk factors or stage of cancer differed significantly between those with and those without CCAP. CONCLUSION: Panoramic radiographs of patients with squamous cell carcinoma of the head and neck show a very high rate of CCAP, a marker of comorbid vascular diseases that may cause treatment complications and affect overall survival.

Capturing patient benefits of treatment.

Findings from the Academy of Osseointegration State of the Science on Implant Dentistry Conference clearly demonstrate that data are lacking regarding both quality of design and adequate outcome measures (standardization, validity, and relevance to patient) to support an evidence-based systematic evaluation of implant efficacy. Despite the dearth of controlled trials and the variability in defining implant survival/success, the preponderance of evidence is viewed as lending support for consideration of dental implant therapy as a safe and predictable alternative to conventional restorations for many applications. However, this minimal conclusion undermines the best intentions of the dental profession, which is striving to substantiate to the patient, third-party providers, and the government the relative benefits and risks of various prosthetic treatment alternatives. The conclusions of multiple consensus conferences have repeatedly stressed that additional research with good strength of evidence following a broad spectrum of outcomes is vital to extend the breadth of conclusions regarding dental implant treatment efficacy. However, without a set of consensus-based core outcome measures addressing pertinent clinical and patient-centered factors, future expensive, time-consuming, and technically complex clinical studies may suffer the same critical flaws seen in the current body of research. It may be possible and useful to establish a core set of well-defined, discriminatory, and feasible outcome measures for common utilization and a hierarchy of additional recommended outcome measures for specific benefit categories. Such a standardized group of outcome measures would be likely to significantly enhance the potential for future research. In addition, with the formation of consensus guidelines, there would be an opportunity for scientific journals to promote the quality of implant dentistry research by suggesting the inclusion of these core outcome measures in studies submitted for publication.

Impact of facial form on the relationship between conventional or implant-assisted mandibular dentures and masticatory function.

STATEMENT OF PROBLEM: It is not clear if the interaction of craniofacial form with type of prosthetic restoration (conventional or implant-assisted) is related to masticatory function in complete denture patients. PURPOSE: The purpose of this study was to investigate the relationships among facial form, skeletal class, alveolar residual ridge heights and masticatory function in subjects treated with implant-assisted or conventional mandibular dentures with lateral cephalometric evaluation. MATERIAL AND METHODS: Data from a previously reported randomized controlled clinical trial were accessed to compare treatment success rates, functional and perceptual outcomes, dietary intake, and craniofacial relationships between mandibular complete dentures and implant overdentures in edentulous diabetic subjects. Evaluation of the digitized post-insertion lateral cephalometric radiographs provided measures of facial form (mesocephalic "medium", brachycephalic "broad and square", dolichocephalic "vertical and long"), skeletal class (Class I, Class II, Class III), and alveolar ridge height (mm), which were compared to results of standardized masticatory tests as evaluated using MANOVA and REGW post-hoc evaluation (α=.05). RESULTS: Masticatory performance on the preferred side was slightly reduced in the dolichocephalic group, compared to brachycephalic and mesocephalic groups (P=.085). Swallowing threshold performance was significantly less in skeletal Class II subjects compared to Class I (P=.034). Maxillary residual alveolar ridge height was significantly less in the brachycephalic group compared to the dolichocephalic group (P<.001). No differences in mandibular ridge height were seen associated with facial form or skeletal class groups. CONCLUSIONS: Facial form may be related to masticatory function with conventional and implant-assisted mandibular dentures, but larger controlled studies are needed to confirm this relationship. Alveolar ridge height is reduced in edentulous subjects with a brachycephalic facial form.

A genetic association study of single nucleotide polymorphisms in FGFR1OP2/wit3.0 and long-term atrophy of edentulous mandible.

BACKGROUND: After dental extraction, the external surface of alveolar bone undergoes resorption at various rates, and a group of patients develop excessive jawbone atrophy. Oral mucosa overlying the atrophied jawbone is unusually thin; therefore, we have hypothesized that excessive jawbone atrophy may be associated with abnormal oral mucosa contraction. FGFR1OP2/wit3.0, a cytoskeleton molecule initially identified in oral wound fibroblasts, has been shown to induce oral mucosa contraction after dental extraction. This study examined the genetic association between single nucleotide polymorphisms (SNPs) of FGFR1OP2/wit3.0 and excessive atrophy of edentulous mandible. METHODS AND FINDINGS: First, the expression of FGFR1OP2/wit3.0 was determined in gingival tissues of 8 subjects before and after dental extraction. In situ hybridization revealed that all subject increased FGFR1OP2/wit3.0 expression in the post-operative oral mucosa tissues; however, significantly high levels of FGFR1OP2/wit3.0 were observed in 3 out of 8 subjects. In a separate study, 20 long-term edentulous subjects (66.4 ± 9.4 years) were recruited. Tag-SNPs in the FGFR1OP2/wit3.0 allele were determined by Taqman-based polymerase chain reaction. The mandibular bone height was determined following the American College of Prosthodontists (ACP) protocol. Subjects with minor allele of rs840869 or rs859024 were found in the highly atrophied group by the ACP classification (Chi square test, p = 0.0384 and p = 0.0565, respectively; Fisher's Exact, p= 0.0515 and p = 0.2604, respectively). The linear regression analysis indicated a suggestive association between rs859024 and the decreased bone heights (Mann-Whitney, p = 0.06). The average bone height of the subjects with rs840869 or rs859024 minor alleles (10.6 ± 3.2 mm and 9.6 ± 3.2 mm, respectively) was significantly smaller than that of those subjects with the major alleles (14.2 ± 4.5 mm, p<0.05). CONCLUSIONS: The patients with the minor allele of rs840869 or rs859024 were associated with excessive atrophy of edentulous mandible. This study may provide the basis for a genetic marker identifying susceptible individuals to develop jawbone atrophy after dental extraction.