Cruciate-retaining Arthroplasty in Patients with Severe Varus Deformity: A Retrospective Comparative Study.

Introduction: There has been debate regarding the advantages of cruciate-retaining over posterior stabilized (PS) knee arthroplasty and vice versa. Many authors consider any coronal plane deformity > 15° as a contraindication for cruciate-retaining total knee arthroplasty. We aimed to compare whether functional outcome, deformity correction, and survivorship of cruciate retaining knee arthroplasty (CR) for severe varus deformity are equivalent to that ofposterior cruciate ligament substituting (PS) for 6 years. Materials and Methods: We conducted a retrospective comparative study among patients who underwent Total Knee Replacement in the Orthopedics Department of a tertiary care hospital between 2016 and 2018 August who had a varus deformity of more than 15°. The first author exclusively performed CR operation (Group A) for all complex knees. In contrast, the second author performed PS surgery (Group B) for any coronal plane deformity over 15°. Clinical evaluation included completing a Knee Society Score (KSS) Evaluation Form. Pre-operative scoring was collected from the hospital database. All clinical examinations and radiographs at the final follow-up were done by the third author, who was unbiased and not involved with the initial patient care. Results: here were 39 patients in Group A (CR) and 28 patients in Group B (PS). In Group A, the mean pre-operative varus was 22.05 ± 2.72° and the pre-operative KSS was 32.94 ± 6.79. Postoperatively, the deformity corrected to a mean valgus of 5.48 ± 1.8° and mean KSS of 89.17 ± 5.79. In Group B, the mean pre-operative varus was 22.14±3.82° and pre-operative KSS was 32.82 ± 5.98. Postoperatively, the deformity corrected to a mean valgus of 4.85 ± 2.1° and mean KSS of 90.17 ± 5.13. The mean insert thickness was 11.76 ± 1.75 mm and 11.42 ± 1.75mm among the CRand PS groups, respectively. Concerning deformity correction (P = 0.19) and functional outcome (P = 0.46), both groups showed equal improvement with a 100% survival rate for 6 years. Conclusion: We concluded that CRknee replacements are possible with excellent functional and radiological outcomes in severe varus arthritic knees with a 100 % survival rate.

Evaluation of accuracy of various impression techniques and impression materials in recording multiple implants placed unilaterally in a partially edentulous mandible- An in vitro study.

BACKGROUND: Various factors like implant angulation, type of impression material and tray type affects the implant impression accuracy. To date limited in-vitro studies were carried out on the implant impression accuracy of unilateral partially edentulous arches. The aim of this research was to evaluate the effects of 0o, 15o and 25o implant angulations on impression accuracy in simulated master casts of unilateral partially edentulous situation using different impression materials and tray selections. MATERIAL AND METHODS: 30 replicas (N = 30) of a resin matrix (control) containing four implant analogues placed unilaterally from the midline till the region of second molar at an angulation of 00, 00, 150 and 250 to the vertical axis of the ridge respectively were obtained by using three impression techniques (stock metal tray, closed custom tray, and open nonsplinted custom tray) and two different impression materials (Polyvinyl-siloxane and polyether). Specific dimensions of the resultant casts were measured using coordinated measuring microscope. Mean linear changes were calculated and statistically analyzed using analysis of variance (ANOVA) and Tukey's post-hoc procedures (p< 0.05). RESULTS: The casts obtained from all three impression techniques had significant differences in dimensions (p<0.05) as compared to that of master model irrespective of impression materials. Comparing the techniques with regard to the parallel implants, no statistical significant difference (p<0.05) was observed with custom tray techniques (closed/open). Whereas while comparing parallel versus non parallel, open tray technique showed superior accuracy compared to closed tray technique as the angulation increased more than 15 degrees. CONCLUSIONS: The influence of material and technique appeared to be significant for highly non axial implant angulations (p< 0.05), and increased angulation tended to decrease impression accuracy. The open tray technique was more accurate with highly nonaxially oriented implants for the small sample size investigated. Key words:Implant impressions, partially edentulous arch, angulated implants.

A finite element study of teeth restored with post and core: Effect of design, material, and ferrule.

BACKGROUND: Different postdesigns and materials are available; however, no consensus exists regarding superiority for stress distribution. The aim of this study was to evaluate the effect of design and material of post with or without ferrule on stress distribution using finite element analysis. MATERIALS AND METHODS: A total of 12 three-dimensional (3D) axisymmetric models of postretained central incisors were made: Six with ferrule design and six without it. Three of these six models had tapered posts, and three had parallel posts. The materials tested were titanium post with a composite resin core, nickel chromium cast post and core, and fiber reinforced composite (FRC) post with a composite resin core. The stress analysis was done using ANSYS software. The load of 100 N at an angle of 45΀ was applied 2 mm cervical to incisal edge on the palatal surface and results were analyzed using 3D von Mises criteria. RESULTS: The highest amount of stress was in the cervical region. Overall, the stress in the tapered postsystem was more than the parallel one. FRC post and composite resin core recorded minimal stresses within the post but the stresses transmitted to cervical dentin were more as compared to other systems. Minimal stresses in cervical dentine were observed where the remaining coronal dentin was strengthen by ferrule. CONCLUSION: A rigid material with high modulus of elasticity for post and core system creates most uniform stress distribution pattern. Ferrule provides uniform distribution of stresses and decreases the cervical stresses.

Digital Cephalometric Tracings by PRO-CEPH V3 Software for Comparative Analyses of Vertical Dimension in Edentulous Patients.

BACKGROUND: Several methods, some physiological, some radiographical and some merely based on experience are taken upon by the practitioner to get him/her close to VDO in the edentulous patients. No single method can however claim to be the perfect answer. Lateral cephalograms have been a standard mode of determining the vertical dimensions in dentate and edentulous patients since the past. Due to unavoidable manual errors, there are chances of variations in the radiographic method too. Advancement in the digital technology has made recording jaw relations faster, simpler and more precise. AIM: This study compared the vertical dimension of occlusion in edentulous patients recorded by using three different physiological methods with the aid of digital cephalometric tracings using indigenously developed PRO-CEPH V3 software. MATERIALS AND METHODS: For the present study a total of 50 dentulous and 25 edentulous patients were selected through inclusion and exclusion criteria. A lateral cephalometric radiograph was taken for all the 50 dentulous subjects at Maximum Intercuspation (VDO) whereas three lateral cephalometric radiographs were obtained for all edentulous patients at the VDO following three different techniques- the Niswonger's method, Phonetics method and Swallowing threshold method. Cephalometric tracings were carried out using indigenously developed PRO-CEPH V3 software. Linear and angular measurement were made and analysed. CONCLUSION: The indigenously developed software PRO-CEPH V3 is capable of making both the linear and angular measurement and therefore provide with relative credibility information regarding the possible VDO in the edentulous patients through cephalometric radiography.

A qualitative analysis to compare the effects of surface machining of conventional denture base resin and two soft liners: a scanning electron microscopic study.

INTRODUCTION: The denture base acrylic resins require adjustments for various reasons. During this process there is an alteration in the surface characteristics of the denture base. Rough surfaces promote the bacterial adhesion and plaque accumulation; therefore it is important to know the character of the surface left by instrumentation on denture base materials. This study evaluated the surface characteristics of the machined surfaces of heat-cured acrylic denture base resin, GC supersoft and Permasoft softliners. MATERIALS AND METHODS: Thirty 15×15×1.5mm acrylic resin specimens were fabricated with each of three acrylic resins: Lucitone 199 denture base resin (Group I), GC supersoft (Group II) and Permasoft (Group III) softliners. They were further divided into three sub Groups A, B and C, in which Sub Group A was control group that is smooth produced against the glass. Sub Group B was produced by machining with the tungsten carbide bur and Sub group C is machined with the stone bur. Each surface was evaluated by a Scanning electron microscope and data were analyzed by analysis of variance followed by Tukey's HSD test. RESULTS: Stone bur produced smoother surface (Ra 3.6681µm± 0.254) on Lucitone199 than the tungsten carbide bur (Ra 5.3881µm ± 0.3373). Carbide bur produced a smoother surface on the GC super soft (Ra 1.617097µm ± 0.191767) and Permasoft softliners (Ra 2.237419µm ± 0.354259). Whereas stone bur produced rougher surface on GC supersoft(Ra 2.6µm) and Permasoft (Ra 4.184839µm ± 0.409869) softliners. CONCLUSION: The present study shows each type of rotary instrument produces its own characteristic surface on each type of denture base materials and that care is needed when selecting the most appropriate instrument to adjust denture base materials. These results can have a significant clinical implication. While using Lucitone 199 stone bur can be used for chair side adjustments. Tungsten carbide bur can be used for GC supersoft and Permasoft softliners to achieve smoother surface.

Prosthodontic perspective to all-on-4® concept for dental implants.

The clinical success and longevity of endosteal dental implants as load bearing abutments are controlled largely by the mechanical setting in which they function. The treatment plan is responsible for the design, number and position of the implants. In biomechanically compromised environment such as poor quality bone, strain to the crestal bone can be reduced by increasing the anterioposterior spread of implants, placement of longer implants and maximizing the number of implants. The All-on-4(®) concept is one such treatment procedure which enlightens us for its use in the completely edentulous patients and which also leaves behind the routine treatment alternative of conventional dentures with successful outcome in the short term, long term and the retrospective studies that have been done in the past. The area of concern for any treatment alternative lies in the success of the prosthesis and its prosthodontic perspective involving the principles of occlusion. This article reviews the All-on-4(®) concept and its prosthodontic aspects.

Estimation of serum superoxide dismutase and serum malondialdehyde in oral submucous fibrosis: a clinical and biochemical study.

BACKGROUND: To estimate the level of lipid peroxidation product (MDA) and the activities of antioxidative enzymes superoxide dismutase (SOD) and the correlation of these parameters in Oral Submucous fibrosis (OSF). AIMS: Estimation of MDA and SOD levels in OSF patients and controls. SETTINGS AND DESIGN: Patients above 15 years of age, who were diagnosed as OSF based upon thorough history, clinical examination and histopathological examination without any underlying systemic diseases, were included in the present study. Equal number of healthy subjects without any deleterious habits and without any clinically obvious oral lesions or systemic diseases were selected as the control group. MATERIALS AND METHODS: The estimation of MDA in serum was done by thiobarbituric acid reactive species method. SOD was assayed by inhibition and autoxidation of adrenaline method. STATISTICAL ANALYSIS USED: The data were analyzed with Student's t-test. RESULTS: Comparison of MDA, SOD among the OSF group and control group showed statistically significant increased levels of malondialdehyde and decreased levels of superoxide dismutase among the OSF groups. Significant changes were not seen in MDA and SOD levels between the different grades of OSF. CONCLUSIONS: From the present study, estimation of lipid peroxidation like MDA was done, which showed increased levels in the OSF group compared to the control group and antioxidant enzyme levels like SOD showed decreased levels in the OSF group compared to the control group. These can be considered as a subject of interest for their possible role in many of the precancerous and cancerous conditions.

Reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous using accepted facial dimensions recorded from dentulous subjects.

The study was undertaken to evaluate the reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous subjects using accepted facial dimensions recorded from dentulous subjects. The hypothesis was that facial measurements can be used to obtain the vertical dimension of occlusion for edentulous patients where no pre-extraction records exist. A total of 180 subjects were selected in the age groups of 50-60 years, consisting of 75 dentate male and 75 dentate female subjects for whom different facial measurements were recorded including vertical dimension of occlusion and rest, and 15 edentulous male and 15 edentulous female subjects for whom all the facial measurements were recorded including the vertical dimension of rest and occlusion following construction of upper and lower complete dentures. The left outer canthus of eye to angle of mouth distance and the right Ear-Eye distance were found to be as valuable adjuncts in the determination of occlusal vertical dimension. The Glabella-Subnasion distance, the Pupil-Stomion distance, the Pupil-Rima Oris distance and the distance between the two Angles of the Mouth did not have a significant role in the determination of the occlusal vertical dimension. The vertical dimension can be determined with reasonable accuracy by utilizing other facial measurements for patients for whom no pre-extraction records exist.

Evaluation of shear bond strength of three different types of artificial teeth to heat cure denture base resin: an in vitro study.

CONTEXT: Bonding of artificial teeth and denture base material remained a significant problem for successful prosthetic treatment. AIM: The purpose of this in vitro study was to evaluate shear bond strength of three different artificial teeth with heat cure denture base material after various surface conditioning methods and thermocycling. MATERIALS AND METHODS: Ninety mandibular first molar denture teeth were selected. They were divided into three groups, Group I: Nanocomposite resin (Veracia), Group II: Composite teeth (Endura), and Group III: Cross-linked acrylic denture teeth (Acry rock). All groups were further subdivided into subgroups based on surface conditioning methods. Subgroup A: No surface conditioning (control group), Subgroup B: Surface conditioning with methyl methacrylate-based bonding agent (Vitacoll), and Subgroup C: Air abrasion with 50 µm aluminum oxide powder particles plus silane-coupling agent (Monobond-S) and Vitacoll bonding agent. Evaluation of shear bond strength of all the specimens was done using universal testing machine. RESULTS: Mean shear bond strength of Group I, Subgroup B (6.87 ± 0.934) showed higher value when compared with Group II, Subgroup B (6.76 ± 1.84) and Group III, Subgroup B (5.66 ± 2.18). The control group (untreated surface) of all three types of artificial teeth used in this study showed significantly lower shear bond strength values than experimental groups (surface conditioning methods; P < 0.05). CONCLUSION: The results of this study suggest that there were significant differences in shear bond strength among control group and surface treatment groups of denture teeth bonded to heat cure denture base resin.

Fabricating a hollow obturator with light-cured resin system.

Tumor resection of a cancer lesion produces maxillary defects that can be easily restored with an obturator to close the defect area. Postsurgical maxillary defects predispose a patient to hypernasal speech, fluid leakage into the nasal cavity, and impaired masticatory function. Therefore, the primary aims of prosthetic rehabilitation in total and partial maxillectomy patients include: separation of oral and nasal cavities to allow adequate deglutition and articulation, possible support of orbital contents and support of soft tissue to restore mid-facial contours. A method of fabricating a simple hollow obturator for maxillectomy patients is described. The use of a relatively long-lasting light cure resin materials in making obturators allows stable, comfortable, and effective obturation. The hollow prosthesis is lightweight and sufficiently flexible to allow relatively simple placement in retentive undercut regions.

Oxidation heat treatment affecting metal-ceramic bonding.

AIM OF THE STUDY: There is dearth of literature regarding the effects of oxidation heat treatment (OHT) as surface pretreatments on bond strength of base metal alloys and porcelain. MATERIALS AND METHODS: Forty-five bar specimens of each two commercially available base metal alloys Mealloy and Wirorn-99 (were fabricated. Dimensions of each specimen were 15.0 × 2.0 × 0.5 mm (according to the ISO 6872-1984). According to the surface pretreatments the samples of the two groups were categorized into three subgroups: With OHT only, with sandblasting only (with Al2O3 of 110 µm) and with OHT and sandblasting. Application of commercially available Duceram porcelain in thickness of 2.00 mm was applied over the surface of metal with the pretreatments. Samples were then placed under SEM for EDX examination to evaluate ionic changes that occurred at the metal-ceramic interface. Flexural bond strength of each sample was calculated under Universal Testing Machine. RESULTS: The one-way ANOVA indicated no significant influence of either metal type (P=0.811) or any surface pretreatment (P=0.757) on the metal-ceramic bond strength. CONCLUSION: OHT resulted in the increase in amount of oxides at the metal-ceramic interface. However, neither metal type nor surface pretreatments affected bond strength.

Accessory soleus muscle: a problem of awareness.

Reports of accessory soleus muscle are rare, perhaps as a result of it often remaining unrecognized. It presents as a swelling behind the ankle and may be mistaken for a tumour or inflammatory lesion, as occurred in the first of a series of three cases. The other two were incidental findings, one in a 30 year old man with an open tibial fracture and the other in a 9 month old child with a club foot. Patients present with either pain or a diagnostic problem. When large, it may make wearing of footwear difficult. Computerized tomography with electromyography enables confirmation of the diagnosis. Pain is relieved by epimysiotomy and when encountered incidentally during surgery, incision of the epimysium is all that is needed. Excision of the muscle may be considered only if wearing of footwear is difficult. The significance of its presence in a case of club foot is unknown. Disinsertion of its insertion was all that was required to obtain surgical correction of the deformity in the present case. Awareness of the condition will prevent unnecessary surgery in asymptomatic cases.