Sundar Ramalingam

Oral manifestations in patients with neurofibromatosis type-1: a comprehensive literature review.

UNLABELLED Oral health status is jeopardized in patients with neurofibromatosis (NF) type-1 (NF-1). The aim of the present study was to comprehensively review the oral manifestations in NF-1 patients. PubMed/Medline and Google-Scholar databases were explored using different keywords. Reviews, commentaries, letters to Editor and articles published in languages other than English were excluded. RESULTS Neurofibromas of oral and perioral soft tissues with subsequent periodontitis, impacted and supernumerary teeth, enlarged alveolar process with dental spacing, morphological changes in teeth and class III molar relationship have been reported in NF-1 patients. Plexiform neurofibromas were reported both in oral soft tissue, maxilla and mandible with evidence of malignant transformation in some cases. Facial skeletal abnormalities, including enlargement of mandibular foramen, increased dimensions of the coronoid and sigmoid notches and notching of the posterior border of the mandible have also been reported. Association between dental caries and NF-1 remains unclear.

Real-time-guided bone regeneration around standardized critical size calvarial defects using bone marrow-derived mesenchymal stem cells and collagen membrane with and without using tricalcium phosphate: an in vivo micro-computed tomographic and histologic experiment in rats

The aim of the present real time in vivo micro-computed tomography (µCT) and histologic experiment was to assess the efficacy of guided bone regeneration (GBR) around standardized calvarial critical size defects (CSD) using bone marrow-derived mesenchymal stem cells (BMSCs), and collagen membrane (CM) with and without tricalcium phosphate (TCP) graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD (diameter 4.6 mm) were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone (NFB) and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo µCT. At the 10th week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness of NFB was similar to that of the native bone in groups 1 and 2 as compared to the NFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical “lock” between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adjunct BMSC therapy.

The effects of surgicel and bone wax hemostatic agents on bone healing: An experimental study.

Background: The biological effects of hemostatic agends on the physiological healing process need to be tested. The aim of this study was to assess the effects of oxidized cellulose (surgicel) and bone wax on bone healing in goats’ feet. Materials and Methods: Three congruent circular bone defects were created on the lateral aspects of the right and left metacarpal bones of ten goats. One defect was left unfilled and acted as a control; the remaining two defects were filled with bone wax and surgicel respectively. The 10 animals were divided into two groups of 5 animals each, to be sacrificed at the 3rd and 5th week postoperatively. Histological analysis assessing quality of bone formed and micro-computed tomography (MCT) measuring the quantities of bone volume (BV) and bone density (BD) were performed. The results of MCT analysis pertaining to BV and BD were statistically analyzed using two-way analysis of variance (ANOVA) and posthoc least significant difference tests. Results: Histological analysis at 3 weeks showed granulation tissue with new bone formation in the control defects, active bone formation only at the borders for surgicel filled defects and fibrous encapsulation with foreign body reaction in the bone wax filled defects. At 5 weeks, the control and surgicel filled defects showed greater bone formation; however the control defects had the greatest amount of new bone. Bone wax filled defects showed very little bone formation. The two-way ANOVA for MCT results showed significant differences for BV and BD between the different hemostatic agents during the two examination periods. Conclusion: Surgicel has superiority over bone wax in terms of osseous healing. Bone wax significantly hinders osteogenesis and induces inflammation.

Does the presence of oral care guidelines affect oral care delivery by intensive care unit nurses? A survey of Saudi intensive care unit nurses

Mechanically ventilated patients rely on nurses for their oral care needs, signifying the importance of nurses in intensive care units (ICUs). This study aimed to evaluate the impact of oral care guidelines on the oral care delivered to mechanically ventilated patients by ICU nurses. A total of 215 nurses were enrolled. Demographic data and oral care practices were recorded through a self-administered survey. Participants governed by oral care guidelines had significantly higher oral care practice scores than their counterparts from ICUs without similar guidelines (P = .034; t = 2.13). Oral care guidelines in ICUs can contribute to reduction of morbidity and mortality caused by ventilator-associated pneumonia.

Guided Bone Regeneration in Standardized Calvarial Defects in Rats Using Bio-Oss and β-Tricalcium Phosphate with Adjunct Platelet-Derived Growth Factor Therapy: A Real-Time In Vivo Microcomputed Tomographic, Biomechanical, and Histologic Analysis.

The objective of the present real-time in vivo experiment was to assess guided bone regeneration (GBR) in standardized calvarial defects using particulate graft material (Bio-Oss) and β-tricalcium phosphate (β-TCP) with adjunct recombinant human platelet-derived growth factor (rhPDGF) therapy. Eighteen female Sprague-Dawley rats with a mean age and weight of 8 ± 0.53 weeks and 250 ± 0.49 g, respectively, were used. Following surgical exposure, a full-thickness standardized calvarial defect was created on the parietal bone using a trephine drill with an outer diameter of 4.6 mm. For treatment, rats were randomly divided into three groups (six rats per group): (1) control; (2) rhPDGF + Bio-Oss, and (3) rhPDGF + β-TCP. Volume of newly formed bone (NFB), bone mineral density (BMD) of NFB, volume of remnant bone particles, and BMD of remnant bone particles were assessed using in vivo microcomputed tomography. Measurements were made at baseline and at 2, 4, 6, and 10 weeks after the surgical procedures. At 10 weeks, all animals were sacrificed and calvarial tissues were assessed histologically. In the control group, a significant increase in BMD of NFB was observed at 6 weeks (mean ± standard deviation [SD], 0.32 ± 0.002 g/mm(3)) (P < .01) from baseline, and the defect did not regenerate completely. In the rhPDGF + Bio-Oss group, mean ± SD volume (2.40 ± 0.25 mm(3)) (P < .01) and BMD (0.13 ± 0.01 g/mm(3)) of NFB significantly increased at 4 weeks and 6 weeks, respectively, from baseline (P < .001). In the rhPDGF + β-TCP group, mean ± SD volume (2.01 ± 0.7 mm(3)) and BMD (0.12 ± 0.02 g/mm(3)) of NFB significantly increased at 4 weeks from baseline (P < .01). In the rhPDGF + Bio-Oss and rhPDGF + β-TCP groups, mean ± SD BMD of remnant bone particles (0.31 ± 0.11 g/mm(3) and 0.23 ± 0.01 g/mm(3)) showed significant reduction at 6 and 10 weeks, respectively, compared with baseline values (1.12 ± 0.06 g/mm(3) and 0.92 ± 0.01 g/mm(3), respectively) (P < .001). Histologic results at 10 weeks showed NBF in the rhPDGF + Bio-Oss and rhPDGF + β-TCP groups. In real time assessment, when rhPDGF was added to β-TCP, BMD and bone hardness significantly increased compared with the other two groups.

Bone Regeneration Using Bone Morphogenetic Protein-2 and Biphasic Calcium Phosphate With and Without Collagen Membrane in Calvarial Standardized Defects: An In Vivo Microcomputed Tomographic Experiment in Rats.

The aim of this in vivo microcomputed tomographic (μCT) experiment was to assess in real time the efficacy of a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and biphasic calcium phosphate (BCP), with and without resorbable collagen membrane (CM), in regeneration of standardized calvarial defects (SCDs) in rats. A total of 30 female Wistar albino rats (n = 10/group) with a mean age and weight of 7.5 months and 275 g, respectively, were used. With the rats under general anesthesia, the calvaria were exposed using full-thickness periosteal flaps and unilateral SCDs of 4.6 mm diameter were created on the left parietal bone. Defects were left untreated (control group) or randomly filled with either BCP soaked in rhBMP-2 and then covered with CM (BMP + BCP + CM group) or BCP soaked in rhBMP-2 alone (BMP + BCP group). In vivo μCT scans were done at baseline and 2, 4, 6, and 8 weeks. Newly formed bone (NFB) and remaining BCP particles were assessed for their volumes (NFBV, BCPV, respectively) and mineral densities (NFBMD, BCPMD, respectively). In vivo μCT results showed scanty amounts of new bone at the peripheries of the defect in the control group. In the other two groups, near complete defect closure was evident at 8 weeks. The mean NFBV after 8 weeks was 4.63 ± 0.96 mm(3), 11.82 ± 1.17 mm(3), and 13.85 ± 1.89 mm(3) for the control, BMP + BCP + CM, and BMP + BCP groups, respectively. After 8 weeks, the mean NFBMD was 0.38 ± 0.03 g/mm(3), 0.24 ± 0.07 g/mm(3), and 0.35 ± 0.03 g/mm(3) for the control, BMP + BCP + CM, and BMP + BCP groups, respectively. After 8 weeks, the mean BCPV and BCPMD values for the BMP + BCP + CM and BMP + BCP groups were 2.73 ± 0.65 mm(3), 0.33 ± 0.08 g/mm(3), 2.49 ± 0.71 mm(3), and 0.28 ± 0.03 g/mm(3), respectively. The present real-time in vivo μCT experiment demonstrated that BMP + BCP, either with or without CM, was effective in promoting bone regeneration within rat SCDs and enabled new bone formation starting as early as 2 weeks.

Efficacy of Mesenchymal Stem Cells as Adjunct to Guided Bone Regeneration in Standardized Calvarial Defects in Rats: An In Vivo Microcomputed Tomographic and Histologic Analysis.

The aim of the present in vivo microcomputed tomographic (μCT), histologic, and biomechanical study was to assess the efficacy of bone marrow-derived mesenchymal stem cells (BMSCs) for promoting guided bone regeneration (GBR) in a standardized rat calvarial defect model. Forty female Wistar albino rats with a mean age of 7.5 months and mean weight of 275 g were used. Following calvarial exposure under general anesthesia, a full-thickness standardized calvarial defect (4.6 mm in diameter) was created. The study animals were randomly divided into four groups based on biomaterials used for GBR: (1) no treatment (negative control); (2) bone graft alone; (3) bone graft placed in the defect and covered with a collagen membrane (CM); and (4) bone graft soaked in BMSCs and covered with a CM. Bone volume and bone mineral density (BMD) of newly formed bone (NFB) and remnant bone particles were determined at baseline and at 2, 4, 6, 8, and 24 weeks postoperative using real time in vivo μCT. Histologic and biomechanical analyses of calvarial specimens were performed at 24 weeks, when the rats were euthanized. Statistically significant differences in volume and BMD of NFB were observed between and within the groups at different data collection periods. Significant increases in volume and BMD of NFB occurred as early as week 2 in all groups except the negative control. While the greatest volume of NFB was observed in the bone graft + BMSC + CM group, BMD of NFB was significantly higher in the bone graft + CM group. Statistically significant decreases in volume and BMD of remnant bone particles were also observed between the groups. Histologic analysis revealed NFB in all groups. The hardness and elastic modulus of NFB in the bone graft + BMSC + CM group were significantly higher than that in the other groups and also similar to adjacent natural bone. This study shows that using adjunct BMSCs with bone graft and CM for guided bone regeneration in standardized rat calvarial defects resulted in the highest quality and quantity of NFB.

Evaluation of bone regenerative capacity following distraction osteogenesis of goat mandibles using two different bone cutting techniques

PURPOSE To compare the regenerative capacity of goat mandibles following sagittal split osteotomy and distraction osteogenesis with a vertical body osteotomy. ANIMALS AND METHODS Bilateral vertical and sagittal body osteotomy was performed on the left and right sides of the mandibles in 18 goats. The distraction period lasted for 10 days at 1 mm/day. Animals were sacrificed at 0, 10, and 35 days post-distraction. Bone mineral density (BMD) and bone volume (BV) were analysed by microcomputed tomography (MCT). Types of bone and cells present in the regenerated defect sites were analysed histologically. RESULTS At 0, 10, and 35 days, BMD was 0.358 ± 0.012, 0.410 ± 0.012, and 1.070 ± 0.019, respectively, for vertical osteotomy and 0.420 ± 0.013, 0.421 ± 0.009 and 1.182 ± 0.030, respectively, for sagittal osteotomy. BV was 973.310 ± 5.048, 1234.589 ± 4.159, and 2121.867 ± 6.519, respectively, for vertical osteotomy and 995.967 ± 2.781, 1755.938 ± 4.379, and 2618.441 ± 21.429, respectively, for sagittal osteotomy at these three time points. BMD and BV differed significantly at all three times. Histological analysis shows that sagittal splitting was characterized by more robust lamellar bone formation bridging the distraction gap than vertical body osteotomy. CONCLUSION Both MCT and histological analyses showed that distraction using the sagittal osteotomy technique resulted in significantly higher BV and BMD than using vertical body osteotomy.

Antibiotic protocol for the prevention of osteoradionecrosis following dental extractions in irradiated head and neck cancer patients: A 10 years prospective study

AIMS OF STUDY The aim of the study was to establish the long term efficacy of a perioperative antibiotic protocol combined with antibacterial mouthwashes in preventing osteoradionecrosis (ORN). MATERIALS AND METHODS Irradiated head and neck cancer patients reporting for dental extractions were prospectively enrolled to the study between January 2002 and December 2009. Selection criteria for the patients included the presence of nonrestorable tooth/teeth in the field of radiation, latency period of 6 months since completion of radiotherapy, radiation dosages >60 Gy, and availability for follow-up. Starting from 10 days preextraction, the patients were prescribed 8th hourly oral amoxicillin 500 mg along with 12th hourly mouthwashes using 10 ml of undiluted chlorhexidine gluconate 0.2% solution. The same prescription was continued for 7 days postextraction. All patients were followed-up at regular intervals until December 2013. RESULTS A total of 89 patients (55 male and 34 female) underwent extractions of teeth which were present in the radiation field. Mean age of the patients was 41.8 years (range 36-54 years) and extractions were done between 12 and 33 months (mean - 15 months) postradiation therapy. Altogether, 232 teeth were extracted (maxilla - 78/mandible - 154) at an average of 2.6 teeth per patients. After a mean follow-up period of 63 months (range 48-123 months) there were no reported cases of ORN. CONCLUSION Based on the results of this study, perioperative oral antibiotics in combination with antibacterial mouthwashes are effective in preventing ORN following dental extractions in irradiated patients.

Efficacy of Mucograft vs Conventional Resorbable Collagen Membranes in Guided Bone Regeneration Around Standardized Calvarial Defects in Rats: A Histologic and Biomechanical Assessment.

Guided bone regeneration (GBR) using a porcine-derived collagen matrix (Mucograft [MG], Geistlich) has not yet been reported. The aim of this histologic and biomechanical study was to compare the efficacy of MG versus resorbable collagen membranes (RCMs) in facilitating GBR around standardized rat calvarial defects. Forty female Wistar albino rats with a mean age and weight of 6 to 9 weeks and 250 to 300 g, respectively, were used. With the rats under general anesthesia, the skin over the calvaria was exposed using a full-thickness flap. A 4.6-mm-diameter standardized calvarial defect was created in the left parietal bone. For treatment, the rats were randomly divided into four groups (n = 10 per group): (1) MG group: the defect was covered with MG; (2) RCM group: the defect was covered with an RCM; (3) MG + bone group: the defect was filled with bone graft particles and covered by MG; and (4) RCM + bone group: the defect was filled with bone graft particles and covered by an RCM. Primary closure was achieved using interrupted resorbable sutures. The animals were sacrificed at 8 weeks after the surgical procedures. Qualitative histologic analysis and biomechanical assessment to identify hardness and elastic modulus of newly formed bone (NFB) were performed. Collected data were statistically analyzed using one-way analysis of variance. Histologic findings revealed NFB with fibrous connective tissue in all groups. The quantity of NFB was highest in the RCM + bone group. Statistically significant differences in the hardness (F = 567.69, dfN = 3, dfD = 36, P < .001) and elastic modulus (F = 294.19, dfN = 3, dfD = 36, P < .001) of NFB were found between the groups. Although the RCM + bone group had the highest mean ± standard deviation (SD) hardness of NFB (531.4 ± 24.9 MPa), the RCM group had the highest mean ± SD elastic modulus of NFB (18.63 ± 1.89 GPa). The present study demonstrated that RCMs are better than MG at enhancing new bone formation in standardized rat calvarial defects when used along with mineralized particulate graft material.