Maxillofacial Reconstruction With Three Dimensional Resin Bone Substitutes as an Alternative to Transition Group of Metals: A Structured Review.

In recent years, novel technologies and techniques have allowed today the production of controlled architecture materials. Although autogenous bone graft substitutes remain the gold standard, enormous defects require supplementary alloplastic substitutes for reconstruction. Polymers have lately been explored for the same purpose and their biological performance has been under research since the last decade. The aim of this review is to analyse maxillofacial reconstruction with three-dimensional resin bone substitutes. A Problem Intervention Comparison Outcomes (PICO) analysis was done and a search was carried out in the Cochrane Database, PubMed, Google Scholar etc databases and a hand search was done to collect the related literature. All articles for maxillofacial reconstruction with three-dimensional resin bone substitutes were scrutinised. The manuscripts published from 1990 till May 2021, were included in this review. A total of 106 articles were obtained from a PICO-based keyword search, and 91 manuscripts were retrieved after excluding the duplicates. Out of these 57 manuscripts were excluded on the basis of title and abstract. From the remaining 34 studies, 17 were excluded after reading the full text based on the inclusion and exclusion criteria. During data extraction, four studies were removed and finally, 13 studies were included in this research. From this scoping review, we could conclude that polymethylmethacrylate and polylactic acid formulations are very promising resin bone substitutes for 3-dimensional reconstruction of maxillofacial defects. However, rigorous long-term clinical trials are needed to validate this conclusion.

Analyzing the Surface Topography of Hafnium Nitride Coating on Titanium Screws: An In Vitro Analysis.

Background The use of surface coatings to enhance the properties lacking in titanium has attracted significant focus in recent times. Hafnium nitride (HfN) coatings could be explored as promising in the osteoinductive properties of titanium implants. HfN exhibits excellent mechanical attributes, such as hardness and wear resistance, and is often used as a coating on high-end equipment for protection. The findings from this research may carve a new path for the production and optimization of HfN coatings to enhance the longevity and augment properties of implant materials. Thus, the present study was orchestrated to elucidate the surface morphology of HfN coating, ultimately contributing to the advancement of dental implant biomaterials. Materials and methods A total of twenty samples of medical grade commercially pure titanium screws (2 mm diameter and 7 mm length) were procured from G. R. Bioure Surgical System Pvt. Ltd., Ravali, Uttar Pradesh, India, and ten samples were reacted with HfN (0.1 M) (Nano Research Elements, Kurukshetra, Haryana, India) in 100% ethanol and stirred continuously for about 48 hours. Then these screw samples were immersed in the prepared colloidal suspension and sintered for two hours at 400 degrees centigrade. The implant screws were affixed onto metal supports. The magnifications for photomicrographs at ×30, ×200, ×1,500, ×3,000, and ×5,000 were standardized. Elementary semi-quantitative analysis of both dental implants was conducted using energy-dispersive X-ray spectrometry (EDX) coupled with the field emission scanning electron microscope (FE-SEM) equipment (JEOL Ltd., Akishima, Tokyo, Japan). The software used for the analysis of the obtained images is SEM Center. Results The surface analysis using the scanning electron microscope (SEM) showed the coating of HfN over titanium screws. The difference in surface morphology of both the group of implant screws can be visualized under 40.0 and 10.0 mm working distance (WD) for both groups. The surface analysis using the EDX of uncoated titanium screws shows five elements in the spectrum: titanium (Ti), oxygen (O), aluminum (Al), carbon (C), and vanadium (V). The EDX of the HfN-coated screws has two additional metals dispersed in the spectrum, hafnium (Hf). The element characteristics are tabulated with their apparent concentration, k ratio, line type, weight percentage, standard label, and factory label for uncoated titanium screws and HfN-coated titanium screws. Conclusion The study evaluated HfN coating over medical grade commercially pure titanium. The surface topography of coated versus uncoated was visualized. The scanning electron microscope (SEM) images showed a homogenous coating over the titanium surfaces, and the EDX showed elemental dispersion of the coated implant. The study aims to provide a comprehensive understanding of the coating's surface morphology, which will aid in the development of more durable and biocompatible implants. This thereby provides a promising scope for further research of this novel metal coating for use in the biomedical sectors, specifically for dental implants.

Evaluation of Corrosive Properties of Hafnium Nitride Coating Over Titanium Screws: An In Vitro Study.

Background Varied surface coatings have been studied time and again in medical sciences. Whether general or dental, studying the performance of coatings aims to assess their potential to improve the durability and longevity of titanium implants, thereby advancing implant technology for enhanced patient outcomes. Various analytical techniques are utilized to assess the performance of the coating, providing insights into its effectiveness in preventing corrosion. The findings of this evaluation will contribute to our understanding of corrosion mitigation strategies for titanium implants and pave the way for the development of more durable implant materials. This article aims to evaluate the corrosion resistance of an innovative metal compound coating applied over titanium implants.  Materials and methods In this study, a total of 20 medical-grade, commercially pure titanium screws were collected. The dimensions of the titanium screws were 2mm x 7mm. Around 10 of these commercially pure titanium screw samples were used as the control group. Hafnium nitride (HfN) (0.1 M) was mixed with 100% ethanol and stirred using a glass rod for about 48 hours. Then 10 of the implant screw samples were immersed in the prepared sol and sintered at 400o C for two hours. The HfN-coated samples were then used as the test group. The corrosion resistance of both groups was tested using electrochemical impedance spectroscopy and potentiodynamic polarization studies. The Nyquist, Bode impedance, and Bode phase angle plots were obtained and studied.  Results Using the Stern-Geary equation, the corrosion current density was calculated. On analysis, these values indicated that the higher impedance in HfN-coated titanium screws showed higher mean corrosion potential (Ecorr = -0.452 V) and corrosion current density ( icorr = 0.0354 µA/cm2) than the uncoated titanium screws.  Conclusion It was concluded that the corrosion properties of HfN-coated titanium screws had higher impedance and consequently the highest corrosion resistance. This thereby provides a promising scope for further research of this novel metal coating for use in the biomedical sectors, specifically for dental implants.

Osteogenic and Biomedical Prospects of Hafnium and Its Compounds: A Scoping Review.

The direct engagement of hafnium (Hf) in biological processes or its critical function in living things is not well understood as of now. Unlike key elements like oxygen, carbon, hydrogen, and nitrogen, which are necessary for life, Hf is not known to have any biological activities or functions. It is essential to acknowledge that scientific research is ongoing and that new findings may have been made. This systematic review aimed to aggregate and analyze the studies that discuss biomedical applications of Hf metal. This systematic review was conducted following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. The following search strategy was used: two independent researchers conducted electronic searches in databases including PubMed, Embase, Cochrane Database of Systematic Reviews, and Google Scholar. The search was conducted up to August 2023 using the Medical Subject Headings (MeSH) terms "transition elements," "hafnium," and "biomedical research." Boolean operators "AND" and "OR" were used to refine the search. Electronic databases, along with hand searches, identified a total of 38 studies. The various database searches resulted in a total of 38 studies, of which 12 were excluded as duplicates, and five were unavailable for full-text data. The remaining 21 full-text articles were then assessed for their eligibility based on the inclusion and exclusion criteria, and finally, a total of 12 studies were included in the present systematic review. Among the 12 chosen studies, six were on cancer-related targeted radiotherapy or chemoradiotherapy, five were on bone or apatite-forming capabilities, and one was on the treatment of inflammatory bowel disease. The common outcome measures included cell proliferation, osteoblast formation, radiotherapy intensification, and immunotherapy. This review outlines an overall picture of the biomedical uses of Hf metal, a transition element, as a potent biomaterial. In conclusion, this transition element, Hf, has some promising scope in the fields of biomedicine, with a special focus in terms of cancer radiotherapy and osteogenic capabilities.

Wear Resistance, Color Stability and Displacement Resistance of Milled PEEK Crowns Compared to Zirconia Crowns under Stimulated Chewing and High-Performance Aging.

Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon-Mann-Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value < 0.05). Zirconia had twice the wear resistance of PEEK (p value < 0.05). Zirconia was more color stable than PEEK (p value < 0.05). PEEK had more displacement resistance than zirconia (p value < 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown.

Effect of Monopoly-coating Agent on the Surface Roughness of a Tissue Conditioner Subjected to Cleansing and Disinfection: A Contact Profilometric In vitro Study.

INTRODUCTION: Tissue conditioners are used to improve the health of the soft tissues of denture-bearing areas. However, leaching of plasticizers from tissue conditioners results in deterioration, which necessitates frequent replacement. The life of these liners varies, but it can be extended by the use of a coating material. AIM: To evaluate the surface roughness of a tissue conditioner with monopoly coating, subjected to denture cleanser and disinfectant. MATERIALS AND METHODS: Sixty disk-shaped specimens of Visco-gel were made and divided into six groups of 10 each (control 1 [C1], control 2 [C2], control 3 [C3], group 1 [M1], group 2 [M2], and group 3 [M3]). Specimens of the control group were not coated with monopoly, while the specimens of the groups 1, 2, and 3 were coated with monopoly. Specimens of C1 and M1 were immersed in distilled water. Specimens of C2, C3, M2, and M3 were immersed into solution of denture cleanser for 8 h at room temperature and immersed in distilled water for the remainder of the 24-h period. C3 and M3 specimens were treated with disinfectant for 10 min before testing the surface roughness. The surface roughness was measured on 1st, 3rd, 5th, 7th, and 14th day, using a contact profilometer. Student's paired t-test was used to compare the mean Ra values within each group. In the present study, P < 0.05 was considered as the level of significance. RESULTS: The mean surface roughness values of M1, M2, and M3 groups were less than C1, C2, and C3, respectively. Among all the groups, M1 showed the least surface roughness values. CONCLUSION: Monopoly-coating agent prevents the deterioration and reduces the surface roughness of the tissue conditioner.

Comparison of Stresses Around Dental Implants Placed in Normal and Fibula Reconstructed Mandibular Models using Finite Element Analysis.

PURPOSE: This study was formulated to evaluate and compare stresses around endosseous implants in various normal and fibula reconstructed mandibular models using finite element analysis method. MATERIALS AND METHODS: CT scan data of a completely edentulous patient and a fibula reconstructed patient was made and the Dicom images were used to design 3-D mandibular models using software. Based on the information from the scan data, various types of reconstructed FEA models were made. Implants (fixtures) and superstructures were then embedded in each model and Von Mises stress around the neck of each implant under a vertical loading of 200 N and Horizontal load of 50 N was calculated using finite element structural analysis software. The results were compared between the reconstructed mandible and their respective normal mandible. RESULTS: Higher stress values were obtained for all the reconstructed types under horizontal loading and in reconstructed models involving larger area of reconstruction the stress were more. In the models involving smaller area of reconstruction like symphysis alone or body alone there is no significant change in the stress values on vertical loading. CONCLUSION: Stresses were comparatively smaller in mandibles involving a smaller area of reconstruction. Hence, fixed prosthesis could be advised and a bar retained over denture for reconstruction for larger area of reconstruction.

Palatal identity appliance: an identification tool in mining accidents.

Fatal accidents are rather common in mining endeavours. Establishing the identification of the deceased in mining accidents can be extremely challenging and the palatal identity appliance is a custom made intra oral device with an embedded memory chip with complete data stored in it which can be very useful in such situations to establish the identity of the dead.

Prosthognathic rehabilitation of a patient with underlying skeletal discrepancy- a case report.

Vertical and anterioposterior maxillary excesses can be treated with a combination of orthopaedic functional appliances, orthodontics and surgery. Treatment varies according to the age, patient reports for treatment. In patients who are treated with either of the above mentioned treatment modalities, if they require prosthetic replacement on a later date, especially of anterior teeth, prosthetic treatment alone does not give an aesthetic outcome. A partially edentulous, elderly patient with underlying skeletal discrepancy (Class II Skeletal deformity) in relation to 12,11,21,22 was treated with a combination of orthognathic surgery and prosthetic rehabilltation. An orthognathic surgery (leforte I osteotomy) was performed to manage vertical maxillary excess, class II skeletal pattern of maxilla and increased lower third facial height. Dental compensations in the mandibular arch were decompensated surgically with lower subapical osteotomy. Prosthetic restorations of missing anterior teeth were done later, such that facial and dental aesthetics. The records showed that the results were stable 12 months after prosthognathic (prosthodontic and orthognathic) treatment. A team approach enabled the female patient in her fifth decade of life, to receive better function, aesthetics and increased quality of life. Doing prosthetic restorations in patients with underlying skeletal discrepancies may become a challenge , which should be achieved without compromising on final outcome, with a calculated risk benefit ratio.

Palatogram revisited.

It is the responsibility of the dentist to fabricate a denture that is fully functional and perfectly esthetic. One prime oral function that has always been overlooked in this regard is speech. It has been thought that speech will follow mere replacement of teeth and that it is the patient's duty to fine tune this function with practice. Phonetics, esthetics, function and comfort form the foundation of a successful prosthodontic treatment. Accurate approximation of palatal contours of a maxillary complete denture to a patient's tongue can improve speech intelligibility, if other factors such as tooth position, occlusal plane and occlusal vertical dimension are satisfactory. Customizing palatal contours of a maxillary complete denture can be accomplished by using tissue-conditioning material, which provides sufficient working time for a patient to pronounce a series of sibilant sounds while recording dynamic impression of the tongue. This article describes a technique of obtaining palatogram and customizing palatal contours of a maxillary complete denture with autopolymerizing acrylic resin to improve the intelligibility of speech.

Full mouth rehabilitation of a patient with mandibular implant screw retained Fp-3 prosthesis opposing maxillary acrylic removable over-denture.

A hybrid denture is one that is fabricated over a metal framework and retained by screws threaded into the implant abutments. The anterior part of a mandibular hybrid denture is fixed on implants while the posterior part of the denture is extended and cantilevered from implants. This article presents the fabrication of a maxillary over-denture opposing mandibular implant retained hybrid prosthesis. A total of four implants were placed in the mandibular arch. Castable abutments were used to produce the optimal angulations. Framework was waxed, cast recovered, and the fit was refined until the framework seated passively on the master cast. The mandibular denture teeth were waxed to the hybrid framework, and a final wax try-in was performed to verify and correct maxillomandibular relations before processing. The prosthesis was inserted after verification of occlusion, retention, and stability. The rehabilitation of edentulous patients with hybrid dentures has been observed to achieve greater masticatory function and psychological satisfaction than with conventional over-dentures. Producing a passive-fitting substructure for a fixed removable screw retained hybrid prosthesis is arguably one of the most technically complex tasks in implant dentistry. The technique presented may not initially produce a perfectly passive framework, but use of disclosing media and adjusting the internal aspect of the casting can result in non-binding, fully seated prostheses.

Comparison of the efficiency of photography-assisted shade selection to visual shade selection.

This study sought to compare the efficacy of digital photographs and graphic software for shade matching to that of conventional visual shade selection. Thirty-one postgraduate students were used and shade selection was analyzed through 1 of 4 different techniques: digital spectrophotometer, conventional visual shade selection, visual shade selection assisted by digital photography, and shade selection by color difference formulas and computer software. Shade selection done with digital photography and graphic software using color difference formulas offered better and statistically significant shade matching compared to conventional visual shade selection and visual shade selection assisted by digital photography.

Evaluation of the influence of blood glucose level on oral candidal colonization in complete denture wearers with Type-II Diabetes Mellitus: An in vivo Study.

BACKGROUND: Candidal colonization in complete denture wearers is a commonly encountered condition that worsens in the presence of untreated Diabetes Mellitus. The aim of this study was to evaluate the correlation between oral candidiasis in denture-bearing mucosa and elevated blood glucose levels in complete denture wearers and to evaluate the effect of oral hypoglycemic drug therapy in controlling oral candidal colonization in denture-bearing mucosa of complete denture wearers with Type II Diabetes Mellitus. MATERIALS AND METHODS: This prospective observational study involved the participation of 15 complete denture wearers with Type II Diabetes Mellitus. The sample collection was made prior and after oral hypoglycaemic drug intervention, by swabbing the rugal surfaces of palatal mucosa, cultured and the density of the candidal colony formed was analyzed and interpreted as colony forming units (CFU) per mL. The candidal samples CFU and corresponding pre- and post-prandial blood glucose levels were estimated, analyzed and compared using Karl Pearson correlation analysis and paired t-test (α = 0.05). RESULTS: The Karl Pearson correlation analysis showed that there was a positive correlation between the blood glucose levels (PPS and FBS) and the candidal colonization (CFU) (P < 0.05). The mean values of all the variables were analyzed using the paired t-test. There was significant reduction in the mean values of blood glucose levels (P < 0.001) and the mean values of the CFU (P < 0.001) following oral hypoglycemic drug therapy. CONCLUSION: Positive correlation was observed between oral candidiasis in complete denture-bearing mucosa and elevated blood glucose levels and oral hypoglycemic drug therapy has a positive effect in controlling oral candidal colonization in complete denture wearers with Type II Diabetes Mellitus.

Effect of four different surface treatments on shear bond strength of three porcelain repair systems: An in vitro study.

BACKGROUND: Ceramic fracture in metal ceramic restorations are serious and pose an aesthetic and functional dilemma both for the patients and the dentist. This has created a demand for the development of practical repair options which do not necessitate the removal and remake of entire restorations. AIM: To evaluate and compare the effect of four different surface treatments on shear bond strength of metal ceramic specimens with three commercially available porcelain repair systems. MATERIALS AND METHODS: Specimens were fabricated with a base-metal ceramic alloy and divided into three groups, to evaluate three porcelain repair systems. Each group was divided into four subgroups based on surface treatment (A) sandblasting, (B) sandblasting followed by etching with 9% HF (Hydrofluoric acid) on surrounding ceramic, (C) Use of a diamond bur on exposed metal followed by etching with 37% H3PO4 and (D) Control groups (D1, D2, D3 for three groups of porcelain repair system which was not subjected to further treatment after finishing with 240 grit silicon carbide paper grinding. Shear bond strength of each group of specimens based on surface treatment were evaluated with a universal testing machine after storing in distilled water for 7 days. One way ANOVA and Tukey-HSD procedure were used to compare the mean values between and among the groups. RESULTS: The mean shear bond strength of group III (10.402 ± 1.055) were significantly higher than group I (8.647 ± 0.990) and group II (8.099 ± 0.600) for all surface treatments. However the mean values of shear bond strength of sub-group A were significantly higher than sub-group C and D but were not significantly higher than sub-group B. CONCLUSION: The results of this study suggest that in fractured metal ceramic restorations the exposed metal surface treated with sandblasting or sandblasting and etching the surrounding ceramic surface with HF can increase the shear bond strength of the repaired metal ceramic area. Porcelain repair systems which contain hybrid composites and 4-META as primer had increased bond strength.

Full mouth rehabilitation of a patient with reduced vertical dimension using multiple metal ce ramic restorations.

Rehabilitation of a patient with severely worn dentition after restoring the vertical dimension is a complex procedure and assessment of the vertical dimension is an important aspect in these cases. This clinical report describes the full mouth rehabilitation of a patient who was clinically monitored to evaluate the adaptation to a removable occlusal splint to restore vertical dimension for a period 1 month and provisional restorations to determine esthetic and functional outcome for a period of 3 months. It is necessary to recognizing that form follows function and that anterior teeth play a vital role in the maintenance of oral health. Confirmation of tolerance to changes in the vertical dimension of occlusion (VDO) is of paramount importance. Articulated study casts and a diagnostic wax-up can provide important information for the evaluation of treatment options. Alteration of the VDO should be conservative and should not be changed without careful consideration.

Evaluation of subgingival microflora in all ceramic restorations with subgingival heavy chamfer finish lines.

Microbial colonization in the gingival sulci of abutment teeth receiving all ceramic retainers with subgingival margins need to be studied to assess the prognosis of periodontal health, which determine the eventual success of fixed partial dentures. This prospective observational study was done to evaluate the quantitative alteration in the microbial flora in the gingival sulci of abutment teeth adjacent to the edentulous space prior and after receiving all ceramic retainers over varying time intervals of 1 week, 1 month and 2 months respectively. Twenty, healthy partially edentulous patients, aged 20-50 years with single missing central incisor were selected for this prospective observational study and their microbial samples were collected from the gingival sulci of abutments adjacent to edentulous space with sterile paper points and cultured and the estimated values for microflora served as controls. The same abutments were prepared to receive all ceramic retainers with subgingival heavy chamfer marginal finish lines. The patients were recalled after 1 week, 1 month, 2 months intervals during which the collected subgingival microbial samples were cultured and the corresponding quantitative microbial alteration in the restored gingival sulci was recorded. The obtained data was statistically analysed using the student t test and repeated analysis of variance test. The results of the study inferred student t test expressed a statistically significant (p < 0.001) progressive increase in gingival sulcular microbial colonisation in the abutment teeth before [M = 2.52 ± SD 1.21(10(6)) CFU/ml] and after receiving all ceramic retainers over varying time intervals of 1 week [M = 3.25 ± SD 1.21(10(6)) CFU/ml], 1 month [M = 4.64 ± SD 1.13(10(6)) CFU/ml] and 2 months [M = 4.75 ± SD 1.16(10(6)) CFU/ml] respectively. The result of repeated analysis of variance test inferred that there was a statistically significant difference (p < 0.001) in the subgingival microfloral count between the pre operative and post operative samples at 1 week, 1 month and 2 months. Subgingivally placed all-ceramic retainers with heavy chamfer finish lines in the abutment teeth demonstrated a statistically significant increase in sulcular microbial colonization over varying time intervals of 1 week, 1 month and 2 months respectively and this may affect periodontal health of abutment teeth progressively.

An In vitro Evaluation of Flexural Bond Strength of Indirect Composites Fused to Metal.

With the advent of newer indirect composite resin materials for crown and bridge prosthesis, it has become imperative to evaluate their strength to serve as long term replacements as a substitute to metal ceramic restorations. This study aimed to evaluate and compare the flexural bond strength of three composite resin veneering material to metal, cured by different methods. Specimen were fabricated with pattern resin by duplicating it with machined metal die and divided into three groups. Three composite resin materials were used in this study. Group (A) received Adoro, Group (B) received Targis and Group (C) received Tescera. The bond strength of all specimens was tested with Lloyd's universal testing machine under three point loading. The highest values for fracture resistance were displayed by light, heat and pressure cured composites followed by composites cured using a temperature of 104 °C and composites with curing temperature of 95 °C. The results indicate that there is a significant difference between the three groups, with the Tescera group specimens exhibiting the highest flexural bond strength. Of the other two groups, Adoro group exhibited higher flexural bond strength than Targis group. The results of this study suggest that Tescera group with curing temperature of 130 °C and pressure of 80 Psi, cured with metal halide unit exhibited the highest flexural bond strength when compared to Adoro and Targis groups.

Comparative Evaluation of Tensile Bond Strength between Silicon Soft Liners and Processed Denture Base Resin Conditioned by Three Modes of Surface Treatment: An Invitro Study.

Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.

Surface bond strength in nickel based alloys.

Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of load onto the specimen was utilized for analyzing bond strength of both alloys. Student t test was conducted and t value obtained was 0.644, and the mean value of flexural bond strength of indigenous alloy is 81.75 with standard deviation of 12.25 and of imported alloy is 84.42 with standard deviation of 10.35, indicating that there was no significant difference between the two alloys. Due to ever increasing cost of imported non-precious alloy the need for a cost-effective replacement was fulfilled by indigenous NFTDC alloy.

Sublingual drug dispensing prosthesis.

Sublingual mode of drug administration is one of the fastest and predictable methods of drug delivery to the patient. Some patients, due to the pathological or psychological reasons, experience considerable difficulty in retaining the sub-lingual tablets. Therefore, often they either swallow or chew the sublingual tablets, thus reducing the efficacy of the medicines. Sublingual drug dispensing prosthesis is a special type of appliance that helps such patients to house the sublingual tablets in special slots in an intra-oral appliance, and thus enhances proposed drug delivery and improves the patient's health.