Vinay V. Kumar

Associations between single-nucleotide polymorphisms of the VEGF gene and long-term prognosis of oral squamous cell carcinoma.

INTRODUCTIONnFunctional polymorphisms (SNPs) of the vascular endothelial growth factor (VEGF) are associated with the incidence of oral squamous cell carcinoma (OSCC). An impact of VEGF-SNPs on prognosis of OSCC patients seems possible. Therefore, correlations between prognostic parameters of OSCC patients and five VEGF-SNPs were determined.nnnMATERIALS AND METHODSnIn a retrospective long-term study, in 113 OSCC patients that underwent curative resections, five VEGF-SNPs (-1154 G/A, +405 G/C, +936 C/T, -2578 C/A, and -460 C/T) were analyzed. Associations between SNPs and prognosis (incidence of local recurrent disease, second cancer, metastases, death, total disease-free survival) were examined.nnnRESULTSnAfter a mean follow-up time of 57.6 months, 32 patients had local recurrences; 15 patients had second cancer, 15 patients metastases, and 23 patients died. The mean disease-free survival was 43.1 months. A significant increased incidence of OSCC in smokers with the VEGF -2578 A/C and -460 C/T SNP was seen (each P < 0.0001). In univariate analysis, patients with advanced OSCCs (T > 2 or N > 0) together with the -1154 A/A allele had a significant worse survival and a worse disease-free survival (both P < 0.04). The same was seen for the +405 G/G SNP (both P = 0.002). In multivariate analysis, only the negative influence of the +405 G/G SNP on survival in advanced OSCCs (T > 2) could be confirmed (P = 0.002).nnnDISCUSSIONnPossible reciprocal interactions between smoking and VEGF-SNP function were observed. Multivariate analysis confirmed the VEGF +405 G/G genotype to be associated with poor survival in advanced OSCCs; a further use of this haplotype as biomarker has to be discussed.

Relation between bone quality values from ultrasound transmission velocity and implant stability parameters – an ex vivo study

AIMnThe objective of this study was to determine the relationship between bone qualities measured by ultrasound transmission velocity (UTV) and primary implant stability parameters measured by radiofrequency analysis (RFA) and push-out test (POT) in an ex-vivo model.nnnMATERIALS AND METHODSnThree blocks of fresh porcine bone samples were obtained from different anatomic regions, correlating to cortical, mixed and cancellous bone. Mechanical bone qualities of these samples were measured using UTV (expressed in m/s) prior to implantation. Three similar implants (4.1xa0×xa011xa0mm, AstraTech OS) were inserted into each of the procured bone blocks. The evaluation of implant-bone interface stability was evaluated by RFA expressed as implant stability quotient (ISQ), and POT measured in Newton (N).nnnRESULTSnFor cortical, mixed and cancellous bone samples UTV values showed a mean of 2049.33, 1728.67 and 1427.67xa0m/s, respectively. For the implants inserted into cortical, mixed and cancellous bone samples the mean RFA (ISQ) values were 94.33, 81.33 and 63.11, whereas the POT values were >2000, 680 and 290xa0N, respectively. There was a strong correlation between UTV values and implant stability parameters that was shown descriptively by scatter box plots.nnnCONCLUSIONnThe bone quality measurements obtained by UTV values significantly correlated to primary implant stability values measured by RFA and push-out test. Moreover, UTV was able to significantly differentiate between the different bone types. This suggested that UTV may be considered as a reasonable instrument to measure bone quality preoperatively and would help clinicians predict primary implant stability before implant insertion.

Retrospective Clinical Study of Marginal Bone Level Changes with Two Different Screw-Implant Types: Comparison Between Tissue Level (TE) and Bone Level (BL) Implant

AimThe objective of this retrospective cohort study was to compare the amount of marginal bone loss (MBL) in a bone-level and a soft-tissue-level implant system, both of which have similar intra-bony shape and surface composition. A subgroup analysis was done to compare the amount of MBL of each implant type in relation to the different vertical placement within the respective groups of implants.Materials and MethodsRecords of all patients who underwent implantation for replacement of teeth using comparable bone level (BL) and soft tissue level implants (TE) from 1st January 2006 to 31st December 2009 were scrutinized. Initial depth of implant placement (IDIP) was measured for all implants. Marginal bone loss was measured in patients whose records were available at time point corresponding to 12, 24 and 36 months post insertion.ResultsOut of a total of 384 implants, 337 implants were included for study. The mean MBL for the BL implants were 0.3, 0.38, 0.48 and for TE implant were 0.6, 0.54 and 0.93 for time periods 12, 24 and 36xa0months respectively. Although there was no statistically significant difference between the two groups at time periods at 6–12xa0months, in later time periods, there was a slightly greater amount of MBL around TE implants as compared to BL implants (pxa0<xa00.001). When comparing the IDIP and MBL in the same implant type, there was a statistically significant (pxa0<xa00.001) positive correlation between the depth of implant placement and the amount of MBL, with deeper placed implants having more bone loss.ConclusionWithin the limitations of this retrospective cohort study design, one can conclude that BL implants had statistically significant lesser MBL as compared to TE in time periods above 12xa0months. Although the difference is statistically significant, the difference may not be clinically significant. The IDIP had an influence on the amount of MBL, with deeper placed implants and screw structure of the implant placed below the bone, having more MBL in the period of study.

Osseoconductivity of a Specific Streptavidin–Biotin–Fibronectin Surface Coating of Biotinylated Titanium Implants – A Rabbit Animal Study

BACKGROUNDnBiofunctionalized implant surfaces may accelerate bony integration and increase long-term stability.nnnPURPOSEnThe aim of the study was to evaluate the osseous reaction toward biomimetic titanium implants surfaces coated with quasicovalent immobilized fibronectin in an in vivo animal model.nnnMATERIALS AND METHODSnA total of 84 implants (uncoated [control 1, nu2009=u200936], streptavidin-biotin coated [test 1, nu2009=u200924], streptavidin-biotin-fibronectin coated [test 2, nu2009=u200924]) were inserted 1u2009mm supracortically in the proximal tibia of 12 rabbits. The samples were examined after 3 and 6 weeks. Total bone-implant contact (tBIC; %), bone-implant contact in the cortical (cBIC; %) and in the spongious bone (sBIC; %) as well as the percentage of linear bone fill (PLF; %) were evaluated.nnnRESULTSnAfter 3 weeks, streptavidin-biotin-fibronectin implants had a significant higher sBIC (pu2009=u2009.043) and PLF (pu2009=u2009.007) compared with the uncoated samples. After 6 weeks, this difference was significant for tBIC (pu2009=u2009.016) and cBIC (pu2009<u2009.001). Additionally, uncoated screws showed a significant higher sBIC when compared with the fibronectin coating (pu2009<u2009.001). Streptavidin-biotin-coated implants showed less bone growth at both time points of all examined parameters when compared with their counterparts (all pu2009<u2009.001).nnnCONCLUSIONSnQuasicovalent immobilization of biotinylated fibronectin with the streptavidin-biotin-fibronectin system on smooth surface titanium shows a beneficial faster osseous healing in vivo. Besides, an antifouling effect of the streptavidin-biotin coating was proven.

Implant supported dental rehabilitation following segmental mandibular reconstruction- quality of life outcomes of a prospective randomized trial.

PURPOSEnThe primary objective of this study was to assess the difference in quality of life (QoL) in patients with dental rehabilitation using two or four implant-supported overdentures following segmental mandibulectomy defect reconstruction with fibula free flap.nnnMATERIAL AND METHODSnThis prospective, parallel designed, randomized clinical study was conducted with a 1:1 ratio. At baseline, all participants already had fibula flap reconstruction for segmental defects of the mandible and rehabilitation with conventional (non-implant supported) removable partial dentures. The participants were then randomized into two groups. Group I received implant supported overdentures on two implants, and Group II received four implants. QoL outcomes were evaluated using standardized questionnaires (EORTC_QLQ c30, H&N35, OHIP, DSI). Outcomes of treatment were evaluated at 6 months (T1) and 1 year (T2) following rehabilitation.nnnRESULTSnA total of 52 patients were randomized into two treatment groups (26 each). After accounting for the loss to lack of follow-up, 22 patients in Group I and 24 patients in Group II were evaluated for QoL at the end of the study. There was a significant improvement in QoL with implant-assisted dental rehabilitation. However there were no significant differences in QoL between the two-implant and four-implant groups.nnnCONCLUSIONnImplant-supported removable overdentures improve QoL outcomes in patients with reconstructed mandibles. This study showed no significant difference in QoL outcomes in patients with two- or four-implant supported removable prostheses.

Curcumin and metformin mediated chemoprevention of oral cancer is associated with inhibition of cancer stem cells

Effective chemoprevention is critical for improving outcomes of oral cancer. As single agents, curcumin and metformin are reported to exhibit chemopreventive properties, in vitro as well as in patients with oral cancer. In this study, the chemopreventive efficacy of this drug combination was tested in a 4‐nitro quinoline‐1‐oxide (4NQO) induced mice oral carcinogenesis model. Molecular analysis revealed a cancer stem cell (CSC)‐driven oral carcinogenic progression in this model, wherein a progressive increase in the expression of CSC‐specific markers (CD44 and CD133) was observed from 8th to 25th week, at transcript (40‐100‐fold) and protein levels (Pu2009≤u20090.0001). Chemopreventive treatment of the animals at 17th week with curcumin and metformin indicated that the combination regimen decreased tumor volume when compared to the control arm (0.69+0.03 vs 6.66+2.4u2009mm3; Pu2009=u20090.04) and improved overall survival of the animals (Pu2009=u20090.03). Assessment of the molecular status showed an overall downregulation of CSC markers in the treatment arms as compared to the untreated control. Further, in vitro assessment of the treatment on the primary cells generated from progressive stages of 4NQO‐induced mice tissue showed a concordant and consistent downregulation of the CSC markers following combination treatment (Pu2009<u20090.05). The treatment also inhibited the migratory and self‐renewal properties of these cells; the effect of which was prominent in the cultures of early dysplastic tissue (Pu2009<u20090.002). Collectively, our observations suggest that the combination of curcumin and metformin may improve chemopreventive efficacy against oral squamous cell carcinoma through a CSC‐associated mechanism.

The Jugaad Technique for Jaw Reconstruction: Denture Based Inverse Planning

AimThe aim of this clinical paper is to introduce a technique to plan for functional maxillofacial reconstructions.Materials and MethodsPreoperative dental casts were made of the patient and mock surgery performed on the casts. A fibula analogue was then placed in an ideal functional reconstruction position. New dentures were fabricated on the fibula analogue and drill holes for the placement of implants were placed through the denture. This denture formed as a guide to position the fibula transplant during surgery.ResultsThis technique was useful in producing functional and rehabilitative outcomes in cases of both maxillary and mandibular reconstructive surgeries.ConclusionThe Jugaad technique—denture based inverse planning—is a cost effective method for planning and executing maxillofacial reconstructions using mock surgery on casts and interim dentures.

Sub-Periosteal Dissection with Denture-Guided Epithelial Regeneration: A Novel Method for Peri-Implant Soft Tissue Management in Reconstructed Mandibles

AbstractBackgroundnIn patients with reconstructed mandibles using free fibula flaps, management of soft tissues around implants supporting dental rehabilitation, is often a clinical problem.AimThe aim of this paper is to describe a new technique, namely Sub-periosteal dissection and denture-guided epithelial regeneration (SD-DGER), as a method of peri-implant soft tissue management in these patients.Materials and methodsThe technique consists of performing a subperiosteal dissection with creation of buccal and lingual flaps. These flaps form the buccal and lingual vestibule. Implants are placed and an interim denture is immediately loaded onto the implants to guide the regenerated epithelium. A keratinized mucosal layer is formed on the bare fibula bone in six months time.ResultsThis technique was successful in producing fixed keratinized epithelial tissue around implants in patients with mandibles reconstructed using the free fibula flap in patients who did not undergo radiotherapy.ConclusionThe sub-periosteal dissection with denture guided epithelial regeneration is a predictable form of peri-implant soft tissue management in selected patients with reconstructed jaws.

A bar-retained overdenture as an external fixator device in a three-dimensional CAD/CAM-based surgical reconstruction of the mandible

Large defects of the human face often cause esthetic as well as functional disorders. We present a new technique for reconstruction of the mandible with prosthodontic rehabilitation in a single surgery, using the implant-supported, bar-retained overdenture as an external fixator. A 58-year-old patient presented with a near total defect of the mandible after cancer resection. For rehabilitation, the mandibular condyles were virtually positioned in the centre of the fossae, and four dental implants were planned. The position of the fibula segments as well as their angulation and lengths were adapted to the implant position. To transfer this plan into surgery, a combined cutting/implant drilling guide was computer-aided printed. To provide the correct angulation of the fibula segments, a CAD/CAM dental arch-bar was made from titanium, fulfilling three functions: to bear the provisional prosthesis; to stabilize the molded fibula as an external fixator; and to position the complete fibula with the prosthesis in a correct relation to the upper jaw and occlusion, as indicated by the prosthesis. This innovative approach of combined prosthodontic and reconstructive rehabilitation could shorten the total reconstruction/rehabilitation time and avoid the need for additional extended surgeries.

Clinicopathologic conference: Multiquadrant expansile fibro-osseous lesion in a juvenile

This paper intends to present clinical, radiologic, and histopathologic features of a case of gigantiform cementoma manifesting in a 14-year-old boy, without any familial involvement. He has been followed for 3 years. Further cases from the literature have been reviewed that confirm a similar clinicopathologic picture. This is the first case report that describes non-familial gigantiform cementoma after the World Health Organisations classification of 2005.