The Use of Hyperbaric Oxygen for the Prevention and Management of Osteoradionecrosis of the Jaw: A Dana-Farber/Brigham and Women's Cancer Center Multidisciplinary Guideline.

BACKGROUND: Osteoradionecrosis of the jaw (ORN) is an infrequent yet potentially devastating complication of radiation therapy to the head and neck region. Treatment options include antimicrobial therapy, local sequestrectomy, resection, and the use of hyperbaric oxygen (HBO). Published data on ORN are difficult to compare because of the lack of a universally accepted classification and staging system, and the literature on the use of HBO to either prevent or successfully manage ORN is controversial and inconclusive. Therefore, we aimed to establish a standard approach for using HBO at our institution. MATERIALS AND METHODS: A literature search was conducted of articles published in the English language between January 1980 and January 2016. Retrieved articles were evaluated by two independent reviewers. Isolated case reports, abstracts, case series, review articles, and cohort studies without a control group were excluded; summary data were extracted from the remaining studies. A panel of experts from Head and Neck Oncology and Oral Medicine from the Dana-Farber Cancer Institute and Brigham and Women's Hospital reviewed the summary data and established multidisciplinary guidelines on the use of HBO for the prevention and management of ORN. RESULTS: Seven studies were evaluated and reviewed by the multidisciplinary panel. There was no consistent evidence in support of HBO for either the prevention or management of ORN. CONCLUSION: Based on the available evidence and expert opinion, routine use of HBO for the prevention or management of ORN is not recommended and is rarely used at our institution. The Oncologist 2017;22:343-350 IMPLICATIONS FOR PRACTICE: The Division of Head and Neck Oncology of Dana-Farber/Brigham and Women's Cancer Center does not recommend the routine use of HBO for the prevention or management of ORN. Adjunctive HBO may be considered for use on a case-by-case basis in patients considered to be at exceptionally high risk who have failed conservative therapy and subsequent surgical resection.

MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy.

BACKGROUND: Mucositis is a highly significant, and sometimes dose-limiting, toxicity of cancer therapy. The goal of this systematic review was to update the Multinational Association of Supportive Care in Cancer and International Society of Oral Oncology (MASCC/ISOO) Clinical Practice Guidelines for mucositis. METHODS: A literature search was conducted to identify eligible published articles, based on predefined inclusion/exclusion criteria. Each article was independently reviewed by 2 reviewers. Studies were rated according to the presence of major and minor flaws as per previously published criteria. The body of evidence for each intervention, in each treatment setting, was assigned a level of evidence, based on previously published criteria. Guidelines were developed based on the level of evidence, with 3 possible guideline determinations: recommendation, suggestion, or no guideline possible. RESULTS: The literature search identified 8279 papers, 1032 of which were retrieved for detailed evaluation based on titles and abstracts. Of these, 570 qualified for final inclusion in the systematic reviews. Sixteen new guidelines were developed for or against the use of various interventions in specific treatment settings. In total, the MASCC/ISOO Mucositis Guidelines now include 32 guidelines: 22 for oral mucositis and 10 for gastrointestinal mucositis. This article describes these updated guidelines. CONCLUSIONS: The updated MASCC/ISOO Clinical Practice Guidelines for mucositis will help clinicians provide evidence-based management of mucositis secondary to cancer therapy.

Multi-institutional, randomized, double-blind, placebo-controlled trial to assess the efficacy of a mucoadhesive hydrogel (MuGard) in mitigating oral mucositis symptoms in patients being treated with chemoradiation therapy for cancers of the head and neck.

BACKGROUND: The objective of this trial was to determine how a mucoadhesive hydrogel (MuGard), a marketed medical device, would fare when tested with the strictness of a conventional multi-institutional, double-blind, randomized, placebo-controlled study format. METHODS: A total of 120 subjects planned to receive chemoradiation therapy (CRT) for treatment of head and neck cancers were randomized to receive either MuGard or sham control rinse (SC) during CRT. Subjects completed the validated Oral Mucositis Daily Questionnaire. Weight, opiate use, and World Health Organization (WHO) oral mucositis (OM) scores were recorded. Subjects who dosed at least once daily during the first 2.5 weeks of CRT were included in the efficacy analysis. RESULTS: Of 120 subjects enrolled, 78 (SC, N=41; MuGard, N=37) were eligible for efficacy analysis. Both cohorts were similar in demographics, baseline characteristics, primary tumor type, and planned CRT regimen. MuGard effectively mitigated OM symptoms as reflected by area under the curve of daily patient-reported oral soreness (P=.034) and WHO scores on the last day of radiation therapy (P=.038). MuGard was also associated with nonsignificant trends related to therapeutic benefit including opioid use duration, and OM scores (WHO criteria) at CRT week 4. Rinse compliance was identical between cohorts. No significant adverse events were reported, and the adverse event incidence was similar between cohorts. CONCLUSIONS: Testing MuGard, a rinse marketed as a device, in a standard clinical trial format demonstrated its superiority to SC in mitigating OM symptoms, delaying OM progression, and its safety and tolerability.

Phase 1b, multicenter, single blinded, placebo-controlled, sequential dose escalation study to assess the safety and tolerability of topically applied AG013 in subjects with locally advanced head and neck cancer receiving induction chemotherapy.

BACKGROUND: Oral mucositis (OM) is a significant toxicity of induction chemotherapy for locally advanced head and neck cancer (LAHNC). The safety and tolerability of AG013, an oral rinse containing recombinant Lactococcus lactis secreting mucosal protectant human trefoil factor 1 (hTFF1), was evaluated in a phase 1b study in LAHNC subjects who received induction with cisplatin, 5-fluorouracil, with or without docetaxel. Preliminary efficacy data were also obtained. METHODS: A total of 25 of 52 LAHNC subjects who were followed during induction cycle 1 developed ulcerative oral mucositis (UOM; World Health Organization grade > 2) and were randomized to AG013:placebo (5:2 ratio) for cycle 2. Dosing schedules of 1, 3, or 6 times daily were evaluated (2 × 10(11) , 6 × 10(11) , and 1.2 × 10(12) colony forming units per day, respectively). OM was evaluated daily from cycle 2, day 1 through 14, using World Health Organization criteria. Pharmacokinetic assessment was also conducted. RESULTS: AG013 bacteria were not detected in blood. Oral live AG013 bacterial and hTFF1 levels in saliva and oral mucosa were equivalent among treatment groups. The most frequently occurring adverse events were nausea, oral pain, fatigue, diarrhea, and mucosal inflammation. Only 12% (3 of 25 adverse events), mainly nausea, were attributed to the investigational medicinal product: AG013 or placebo. Efficacy analysis showed a 35% reduction in percentage of days with UOM in AG013-subjects versus placebo. All placebo subjects experienced ≥ 2 days of UOM, whereas 29% of AG013 subjects had UOM for 0 or 1 day. AG013 use resulted in fewer unscheduled office and emergency room visits. No differences were noted in mouth and throat soreness, opioid use, or gastrostomy tube placement. CONCLUSIONS: AG013 was safe and well tolerated. Preliminary efficacy data support further study.

A randomized, double-blind, placebo-controlled trial of misoprostol for oral mucositis secondary to high-dose chemotherapy.

PURPOSE: Misoprostol, a synthetic analog of prostaglandin E1, has anti-inflammatory and mucosa-protecting properties. The objective of this study was to evaluate the efficacy of misoprostol oral rinse in reducing the severity of oral mucosal injury caused by high-dose chemotherapy. METHODS: The study used a randomized, double-blind, placebo-controlled, parallel-group design. Oncology patients receiving myeloablative high-dose chemotherapy, in preparation for a hematopoietic stem cell transplant, were randomized to misoprostol or placebo rinse. The primary outcome measure was the severity of oral mucositis, measured using the modified Oral Mucositis Index. Additional outcome measures included the severity of mouth pain (measured using a Visual Analog Scale and the Pain Affect Faces Scale), duration of hospital stay, and days on total parenteral nutrition. RESULTS: This study was originally planned to accrue 160 subjects but was terminated early due to revised sponsor research priorities. The intent-to-treat population consisted of 22 subjects randomized to misoprostol rinse and 26 subjects randomized to placebo rinse. There was no significant difference between the two groups in mucositis or pain severity. In both groups, duration of hospital stay was approximately 19 days, and number of days on total parenteral nutrition was 17-18 days. There were no serious adverse events attributable to misoprostol rinse. CONCLUSIONS: Although this study did not find a beneficial effect of a misoprostol rinse in mucositis secondary to high-dose chemotherapy, the small sample size limits the strength of this conclusion. Given the proposed importance of the prostaglandin pathway in the pathogenesis of oral mucositis, additional studies are warranted.

Role of the cyclooxygenase pathway in chemotherapy-induced oral mucositis: a pilot study.

GOALS: Oral mucositis can be a significant and dose-limiting complication of high-dose cancer therapy. Mucositis is a particularly severe problem in patients receiving myeloablative chemotherapy prior to bone marrow or hematopoetic stem cell transplant (HSCT). The cyclooxygenase (COX) pathway mediates tissue injury and pain through upregulation of pro-inflammatory prostaglandins, including prostaglandin E2 (PGE2) and prostacyclin (PGI2). The objective of this small (n = 3) pilot study was to examine the role of the COX pathway in causing mucosal injury and pain in chemotherapy-induced oral mucositis. MATERIALS AND METHODS: We collected blood, saliva, and oral mucosal biopsy specimens from three autologous HSCT patients at the following time-points before and after administration of conditioning chemotherapy: Day -10, +10, +28, and +100, where day 0 is day of transplant. RNA extracted from full-thickness tissue samples was measured by RT-PCR for the following: COX-1, COX-2, microsomal prostaglandin E synthase (mPGES), IL-1beta, and TNF-alpha. Blood and saliva samples were measured by ELISA for PGE2 and PGI2, which are markers of COX activity. Severity of oral mucositis was determined using the Oral Mucositis Index. Severity of pain due to oral mucositis was measured using a Visual Analog Scale. Relationships between the different variables were examined using Spearman rank correlation coefficients. MAIN RESULTS: Mean mucositis and pain scores increased significantly after administration of chemotherapy and then gradually declined. The correlation between changes in mucositis and pain scores was strong and statistically significant. The following additional correlations were statistically significant: between tissue COX-1 and pain; between tissue mPGES and pain; between salivary PGE1 and pain; between salivary PGI2 and pain. Other relationships were not statistically significant. CONCLUSIONS: Our finding of significant associations of pain scores with tissue COX-1 and mPGES, as well as salivary prostaglandins, is suggestive of a role for the cyclooxygenase pathway in mucositis, possibly via upregulation of pro-inflammatory prostaglandins. However, our small sample size may have contributed to the lack of significant associations between COX-2 and other inflammatory mediators with mucosal injury and pain. Thus, additional studies with larger numbers of subjects are warranted to confirm the involvement of the cyclooxygenase pathway in chemotherapy-induced mucositis.

Emerging drugs for chemotherapy-induced mucositis.

BACKGROUND: Chemotherapy-induced mucositis is an increasingly recognized problem in cancer management, preventing full doses of treatment being given, compromising cure rates and reducing quality of life. Symptoms include mouth pain and ulceration, esophagitis, abdominal pain, bloating, and diarrhea. It is associated with increased infections and occasional mortality, and its palliation is very expensive. The pathobiology of mucositis is complex, and agents that target mechanisms to prevent mucositis or accelerate healing are in high demand. OBJECTIVES: To review existing and potential treatments for chemotherapy-induced mucositis in the context of current knowledge of pathobiology. METHODS: We searched for mucositis of any region of the gastrointestinal tract using Medline, the Pharmaprojects database and listed patents. RESULTS/CONCLUSIONS: There are many agents in varying stages of development for chemotherapy-induced mucositis. The field is complicated by the question of whether treatments should be developed as drugs or as medical foods, and whether the burden of proof of efficacy and safety should be different.

Topical Clonazepam Solution for the Management of Burning Mouth Syndrome: A Retrospective Study.

AIMS: To evaluate and compare the effectiveness of two concentrations of topical clonazepam solution in improving symptoms of burning mouth syndrome (BMS). METHODS: A retrospective chart review was conducted of patients diagnosed with BMS and managed with topical clonazepam solution between 2008 and 2015. A 0.5-mg/mL solution was prescribed until 2012, when this was changed to a 0.1 mg/mL solution. Patients were instructed to swish with 5 mL for 5 minutes and spit two to four times daily. The efficacies of the two concentrations were compared using patient-reported outcome measures at the first follow-up, including the reported percentage of improvement in burning symptoms and the change in burning severity from baseline ranked on an 11-point numeric rating scale (NRS). Response to treatment was compared between the two concentrations using Wilcoxon rank sum test. RESULTS: A total of 57 subjects were included, 32 in the 0.1-mg/mL cohort and 25 in the 0.5-mg/mL cohort, and evaluated at a median follow-up of 7 weeks. The median overall percentage improvement was 32.5% in the 0.1-mg/mL cohort and 75% in the 0.5-mg/mL cohort. The median reduction in NRS score was 0.5 points in the 0.1-mg/mL cohort and 6 points in the 0.5-mg/mL cohort. The use of either outcome measure revealed that the response to treatment with the 0.5-mg/mL solution was superior to that of the 0.1 mg/mL solution (P < .01). CONCLUSION: These findings suggest that a 0.5-mg/mL topical clonazepam solution is effective in the management of BMS. Future randomized clinical trials are warranted.

Safety and tolerability of topical clonazepam solution for management of oral dysesthesia.

OBJECTIVES: The aim of the study was to determine the absolute and relative safety of treatment with 2 concentrations of topical clonazepam solution (0.1 mg/mL, 0.5 mg/mL) for management of oral dysesthesia. STUDY DESIGN: The study was a retrospective chart review of patients diagnosed with oral dysesthesia and managed with topical clonazepam solution (swish and spit) between 2008 and 2015. The relative safety of the 2 concentrations was evaluated in terms of occurrence of adverse drug reactions (ADRs) and occurrence of change to treatment plan secondary to ADRs. RESULTS: For the study, 162 patients were included-84 patients in the 0.1 mg/mL cohort and 78 in the 0.5 mg/mL cohort, who were evaluated for a median follow-up period of 6 weeks. Thirty-eight (23%) patients developed ADRs. The most frequently reported ADR was sedation (62% of ADRs), followed by altered mental status and dizziness (7% each). Dose adjustments were required in 9 patients (6%) and treatment discontinuation in 13 (8%). ADRs were more frequently reported in the 0.5 mg/mL cohort, but no significant difference was found in terms of occurrence of ADRs, change to treatment plan secondary to ADRs, or types of ADRs (P > .05). CONCLUSIONS: Treatment with topical clonazepam solution in either 0.5 mg/mL or 0.1 mg/mL concentration appears to be safe and well-tolerated. Future prospective studies are needed to confirm this finding.

Oral health status and risk of bacteremia following allogeneic hematopoietic cell transplantation.

OBJECTIVES: The aim of this study was to evaluate the impact of oral health status on bacteremia risk in a cohort of patients with acute myeloid leukemia (AML) who underwent chemotherapy followed by myeloablative allogeneic hematopoietic cell transplantation (allo-HCT). STUDY DESIGN: A retrospective study was conducted in patients with AML from 2007 to 2011. Oral health status was determined from a pre-allo-HCT dental evaluation. Positive blood cultures were recorded from AML induction to post-allo-HCT day +60. Organisms that caused bacteremia were classified as "of possible oral source" by a blinded microbiologist. Two-sided Fisher's exact test was used to compare the oral health status of the entire cohort with that of patients with blood cultures of potential oral source. RESULTS: Pre-allo-HCT dental evaluations were completed in 91 (99%) of 92 patients. Of these 91 patients, 13 (14%) with dental pathology (13 of 13 [100%]) completed all required dental treatment before allo-HCT. Bacteremias occurred in 63 of 92 patients (68%), and 12 (19%) of 63 patients had positive blood cultures of potential oral source. Of these, 1 of 12 patients developed bacteremia during AML induction, and 11 of 12 developed bacteremia during allo-HCT. CONCLUSIONS: Oral health status was not associated with risk of bacteremia of potential oral source either at AML induction or consolidation or at allo-HCT.

Dimensional stability of the alveolar ridge after implantation of a bioabsorbable bone graft substitute: a radiographic and histomorphometric study in rats.

This study evaluated reconstruction of the alveolar ridge after molar extraction in rats with bioabsorbable bone repair scaffolds. The material was prepared from the unsaturated polyester poly(propylene glycol-co-fumaric acid) (PPF), which may be cured in situ to form a porous scaffold. The intention is to use this material either as a stand-alone bone graft substitute or as an extender to autograft harvested from mandibular reconstruction sites. The bioactivity of the graft substitute was investigated in a rat residual ridge resorption model. PPF bone repair material was injected into the defect site, where it cross-linked in situ in the presence of a hydroxyapatite (HA) filler and effervescent agents. The PPF-based material develops porosity during an in situ cure by generating carbon dioxide during the effervescent reaction of citric acid and sodium bicarbonate. The incorporation of HA promotes osteoconduction within the bone repair scaffold. In this study, bioactivity of the porous scaffold was evaluated as a function of HA particle size (micrometer-sized vs nanometer-sized particles). The maxillary or mandibular molars on the right side were extracted from 96 adult Sprague-Dawley rats. A 2-mm round bur was used to create a uniform trench defect measuring 2 mm in diameter, 2 mm in depth, and 4 mm in length at each extraction site. The defect site was (1) treated with PPF bone repair material containing nanometer-sized HA, (2) treated with PPF material containing micrometer-sized HA, (3) treated with demineralized freeze-dried bone allograft, or (4) left untreated. Rats were sacrificed at 2, 4, 7, and 12 weeks postoperative. Resorption of the residual alveolar ridge was assessed by radiographic outcomes. Bone ingrowth through the defect site was measured by histomorphometric outcomes. Mandibular and maxillary ridge heights increased for all treatments used in this study. There were no clinical indications that addition of either of the PPF bone repair materials retarded hard- or soft-tissue healing of the extraction sites. Although not statistically significant, the mandibular defects treated with PPF containing nanometer-sized HA healed at a faster rate as determined by ridge height and new bone formation measurements when compared with the other treatments. These findings suggest the feasibility of using PPF bone graft substitutes for oral-maxillofacial applications.

An Outcomes Study of 40 Years of Graduates of a General Practice Dental Residency.

Assessing program quality and outcomes is essential to improve postgraduate dental education. This study's aims were to document career direction and practice patterns of graduates of the Brigham and Women's Hospital (BWH) General Practice Residency (GPR), to compare BWH GPR outcomes to those of other American GPRs, and to identify characteristics of the BWH GPR program that trainees valued. This was a retrospective cohort study with a sample comprised of BWH GPR graduates between 1973 and 2013. Outcomes examined included pursuit of specialty training and positions on academic or hospital staff. Data sources were a survey of BWH GPR graduates and published national surveys. Of the 190 BWH graduates (95% of total) who were located and contacted, 133 (70% response rate) completed the survey. Compared to national survey data, BWH GPR graduates were significantly more likely to be specialists, full-time hospital staff, or full-time or part-time dental school faculty. Most BWH graduates (96.2%) ranked the program as outstanding or good. Faculty characteristics were considered by BWH graduates to be the most important factors in judging program quality. Since faculty characteristics were the most important factors in residents' judgment of program quality, GPR programs should recruit, maintain, and develop a quality faculty in order to attract students.

Current understanding of the relationship between periodontal and systemic diseases.

Periodontal disease (PD) is among the most common infectious diseases affecting humans. While the burden of periodontal disease on oral health has been extensively investigated, a possible specific relationship between the disease and systemic health is a relatively new area of interest. More recently it has been suggested that PD has an etiological role in the development of atherosclerotic cardiovascular disease, diabetes mellitus, and preterm low-birth weight, among others. In this review, we critically evaluate the current knowledge on the relation between PD and systemic diseases overall, and specifically with cardiovascular diseases. The best available evidence today suggests that the infection and inflammatory reaction associated with PD may contribute toward systemic disease. It is critical that dentists and physicians are well informed of the potential general health impact of periodontal disease so that they are in a position to knowledgeably counsel patients. 

Oral Medicine referrals at a hospital-based practice in the United States.

OBJECTIVE: The objective of this study was to characterize the outpatient oral medicine (OM) clinic at Brigham and Women's Hospital (BWH), with particular emphasis on patient demographic characteristics and referral patterns. MATERIALS AND METHODS: A retrospective case record review of all initial consultations with OM experts at BWH from 2008 to 2010 was conducted. Data included demographic information, type of medical insurance, reason for referral, referring doctor's specialty, and distance between the patient's home and the referring doctor as well as BWH, number of prior doctors seen for the presenting problem (per patient report), tests ordered at the consultation visit, and clinical diagnoses. RESULTS: There were 1043 new outpatient consultation visits. Patients lived a median distance of 9.5 miles from the referring doctor and 18.9 miles from BWH and saw a median of one doctor (range 0-9) before consultation. Two thirds of patients were referred by physicians. The most common diagnoses included immune-mediated mucosal conditions (27.2%), orofacial pain disorders (25.1%), benign tumors or neoplasms (10.3%), and dysplasia and cancerous conditions (7.6%). Biopsy was the most frequent test performed at consultation. CONCLUSIONS: Patients with oral conditions often see more than one doctor, before being referred to an OM expert and typically travel twice the distance to the expert compared with that between their home and the referring doctor. Equal efforts should be made to increase awareness of the importance of the specialty of OM among dentists, physicians, and the public.

A phase III, randomized, double-blind, placebo-controlled, multinational trial of iseganan for the prevention of oral mucositis in patients receiving stomatotoxic chemotherapy (PROMPT-CT trial).

Microfloral invasion and colonization of oral cavity mucosal tissues contribute to the pathophysiology of ulcerative oral mucositis (UOM). Iseganan is an analog of Protegrin-1, a naturally occurring peptide with broad-spectrum microbicidal activity. A randomized, double-blind, placebo-controlled study was conducted to evaluate iseganan in preventing UOM after stomatotoxic therapy. Patients received an oral rinse of iseganan 9 mg or placebo, swished/swallowed 6 times daily, starting with stomatotoxic therapy and continuing for 21-28 days. One hundred sixty three and 160 patients, respectively, were randomized to receive iseganan or placebo. One hundred and two patients (32%) were affected by a drug dispensing error, caused by a flawed computerized allocation system. Among all 323 patients, analyzed according to randomization assignment, 43% and 33% of iseganan and placebo patients, respectively, did not develop UOM (P = 0.067). On an 11-point scale, iseganan patients experienced less mouth pain (3.0 and 3.8 (P = 0.041), throat pain (3.8 and 4.6 (P = 0.048)), and difficulty swallowing (3.9 and 4.7 (P = 0.074)), compared to placebo patients. On the 5-point NCI CTC scale, iseganan patients experienced lower stomatitis scores (1.6 and 2.0 (P = 0.0131). Iseganan was well tolerated; no systemic absorption was detected. Iseganan is safe and may be effective in reducing UOM and its clinical sequelae.

Gene expression profiling by DNA microarrays and its application to dental research.

UNLABELLED: DNA microarray technology has been used for genome-wide gene expression studies that incorporate molecular genetics and computer science skills on massive levels. The technology permits the simultaneous analysis of tens of thousands of genes for the purposes of gene discovery, disease diagnosis. improved drug development, and therapeutics tailored to specific disease processes. OBJECTIVE: In this review, the two most common microarray technologies and their potential application to dental research will be discussed. The authors review current articles pertaining to the technologies and analysis of mRNA expression using DNA micro-arrays and its application to dental research. Since many genes contribute to normal functioning, research efforts are moving from the search for a disease specific gene to the understanding of the biochemical and molecular functioning of a variety of genes and how complicated networks of interaction can lead to a disease state, such as oral cancer. With the incorporation of DNA micro-array based research, we can look forward to more accurate diagnosis and surgical treatment/drug-delivery therapy based on an individual patient's genetic profile.

Oral complications of cancer therapy.

The mouth is a frequent site of complications arising from drug or radiation cancer therapy, with mucositis, xerostomia, osteoradionecrosis, and local infections being the most common. From the stand-point of dose limitation, treatment breaks, quality of life, and health economic outcomes, mucositis is the most significant acute oral toxicity. Xerostomia, a chronic side effect of radiation, involves the salivary gland tissue, and results in changes in taste, tissue resilience, and an increased risk of caries and periodontal disease. While the incidence of osteoradionecrosis seems to be decreasing, the chronicity and symptoms of this festering bony condition are especially difficult for patients. Local oral infections resulting from the overgrowth of opportunistic organisms or the activation of latent viruses are so common as to warrant a prophylactic approach in many cases. A surge of investigational interest has been directed at understanding the mechanisms of these stomatotoxicities and at developing treatment strategies to combat them.

Evaluation of a porous, biodegradable biopolymer scaffold for mandibular reconstruction.

PURPOSE: Bioresorbable bone graft substitutes could eliminate disadvantages associated with the use of autografts, allografts, and other synthetic materials. The authors investigated the osteoinductive capacity of a bioresorbable bone graft substitute made from the unsaturated polyester poly(propylene glycol-co-fumaric acid) (PPF) for mandibular reconstruction in a rat model. The eventual intention is to use this material either as a stand-alone bone graft substitute or as an extender to autograft harvested from mandibular reconstruction sites. MATERIALS AND METHODS: The PPF bone graft was crosslinked in the presence of a hydroxyapatite filler and effervescent foaming agents to develop porosity in situ by generating carbon dioxide during the effervescent reaction of citric acid and sodium bicarbonate. The latter reagents are responsible for foam formation and expansion, resulting in a polymeric scaffold with pore sizes in the range of 100 to 500 microm. Twenty adult Sprague-Dawley rats had 3-mm-diameter cortical defects decorticated on the outer aspect of their left mandibular ramus using a Hall drill. Animals were divided into 2 groups of 10 animals each. Animals in group A were treated with implantation of the PPF-based bone graft substitute. Implants were applied buccally to defects on the left side. In group B animals with similar defects, the drill holes were left to heal unaided. The amount of new bone formation and the presence of an inflammatory infiltrate were evaluated at 7 weeks postoperatively. RESULTS: Histologic analysis of the healing process revealed enhanced in vivo new bone formation with the PPF bone graft substitute. These findings were corroborated by the histomorphometric analysis of new bone formation. DISCUSSION: Results of this study demonstrated biocompatibility of the porous PPF-based scaffold in a mandibular defect. CONCLUSIONS: These findings may have applicability to the further development of bone graft substitutes for oral/maxillofacial applications.

Deciphering gene expression profiles generated from DNA microarrays and their applications in oral medicine.

Genome-wide monitoring of gene expression profiles using DNA microarrays provides a unique approach to exploring the biological processes underlying oral diseases and disorders by providing a comprehensive survey of a cell's or tissue's transcriptional mapping. This revolutionary technology allows for the simultaneous assessment of the transcription levels of tens of thousands of genes, and of their relative expression between normal and diseased cells. As microarray data analysis evolves, there is a widespread hope that microarrays will significantly impact our ability to explore the genetic changes associated with disease etiology and development, ultimately leading to the discovery of new biomarkers for disease diagnosis and prognosis prediction as well as new therapeutic tools. The goal of this manuscript is to review 2 of the most commonly used microarray technologies, provide an overview of data analyses involved in a typical microarray experiment, and comment upon the application of microarrays to oral medicine.