Niraj Mishra

Changes in alveolar bone density around immediate functionally and nonfunctionally loaded implants

STATEMENT OF PROBLEM Few studies compare the radiographic changes in bone density associated with immediate implant loading protocols. PURPOSE The purpose of this longitudinal study was to quantitatively assess radiographic changes in alveolar bone density around immediate functionally and nonfunctionally loaded implants. MATERIAL AND METHODS A prospective longitudinal study was conducted in which 20 participants with partially edentulous mandibles received implants that were immediately loaded either functionally (IFL) or nonfunctionally (INFL). Standardized intraoral periapical radiographs were made at baseline, 3, and 6 months. These were digitized and analyzed using the histogram tool of the GNU Image Modulation Program for changes in alveolar bone density at crestal and lateral apical levels around the implant. RESULTS An increase in the mean lateral apical pixel grayscale values of 4.68 ±0.80 at 3 months and 4.15 ±0.29 at 6 months was observed with IFL, while INFL demonstrated an increase of 5.66 ±0.53 at 3 months and 6.07 ±0.59 at 6 months. A decrease in the mean crestal pixel grayscale values of -24.40 ±7.41 with IFL and -16.86 ±5.14 with INFL was found from baseline to 3 months. CONCLUSIONS On the basis of this longitudinal study, it was concluded that immediate loading stimulated alveolar bone formation at 6 months after implant placement. The immediate functional loading of implants resulted in a significantly greater degree of bone demineralization at the alveolar crest from implant placement up to 3 months compared with immediate nonfunctional loading.

Two-Piece Denture-Obturator Prosthesis for a Patient with Severe Trismus: A New Approach

Prosthetic intervention with maxillary obturator prosthesis is necessary to restore the contours of resected palate and to recreate the functional separation of the oral cavity and sinus and nasal cavity. Trismus occurs most frequently in maxillectomy patient following surgical procedure. Absence of graft placement and healing by secondary intention always results in healing contracture and trismus. Trismus could also be a result of post radiation sclerosis and scarring of muscles. Two-piece denture-obturator prosthesis is an alternative management to conventional acrylic resin obturator prosthesis for the patient with severe trismus as patient could not insert a large prosthesis in the mouth. The use of flexible or resilient material affords the opportunity to engage in undercut areas, needed to help in the retention of the prosthesis, without causing trauma to the soft, often sensitive, and easily irritable tissues.

Improving prosthetic prognosis by connective tissue ridge augmentation of alveolar ridge

The contour of edentulous ridge should be carefully evaluated before a fixed partial denture is undertaken. The ideal ridge height and width allows placement of a natural looking pontic which facilitates maintenance of plaque-free environment. The localized alveolar ridge defect refers to the volumetric deficit of the limited extent of bone and soft tissue within the alveolar process. Such type of ridge defects can be corrected by surgical ridge augmentation that can be accomplished by the addition of either soft or hard tissues. This article describes a procedure of surgical connective tissue augmentation of a localized deficient alveolar ridge in the maxilla, followed by fixed partial denture, enhancing the esthetics, function and health.

Cerrobend shielding stents for buccal carcinoma patients

Buccal carcinoma is one of the most common oral malignant neoplasms, especially in the South Asian region. Radiotherapy, which plays a significant role in the treatment of this carcinoma, has severe adverse effects. Different types of prosthesis may be constructed to protect healthy tissues from the adverse effects of treatment and concentrate radiation in the region of the tumor mass. However, the technique for fabrication of shielding stent with Lipowitzs alloy (cerrobend/Woods alloy) has not been well documented. This article describes detailed technique for fabrication of such a stent for unilateral buccal carcinoma patients to spare the unaffected oral cavity from potential harmful effects associated with radiotherapy.

A pilot study to evaluate the efficacy of cerrobend shielding stents in preventing adverse radiotherapeutic effects in buccal carcinoma patients.

BACKGROUND Radiation stents made of Lipowitz metal or cerrobend alloy are commonly used to shield uninvolved tissues from electron beams used in therapeutic radiation treatment of head and neck cancers. However, studies investigating the efficacy of cerrobend shielding stent in patients with unilateral buccal carcinoma remain rare. PURPOSE To evaluate the efficacy of cerrobend shielding stents in minimizing the potential adverse effects of radiation on oral tissues in buccal carcinoma patients. MATERIALS AND METHODS Twenty.eight participants were selected for the study based on predetermined inclusion criteria, out of which four participants were lost to follow-.up. Half of the remaining participants. (N = 12) were randomly given cerrobend shielding stent and the remaining 12 formed the control group. The effects of radiotherapy were evaluated by using Radiation Therapy Oncology Group. (RTOG) 0435 Head and Neck adverse effects grading tool. All participants were evaluated for xerostomia, mucositis, dysphagia, salivary changes, dysguesia, pain, trismus and radiation caries at baseline and 1 and 3. months post.radiotherapy. RESULTS All adverse effects were higher in control compared to study group, with post therapy difference for pain in swallowing, salivary changes, mucositis, dysphagia, dry mouth and caries being statistically significant. CONCLUSIONS Cerrobend alloy can be used effectively as shielding stent to reduce the adverse effects associated with external beam radiation therapy in unilateral buccal carcinoma patients.

Management of maxillectomy defect with a hybrid hollow bulb obturator

A woman having already undergone maxillectomy came to the department complaining of difficulty in eating and speech. During the construction of an obturator, the bulb area should be hollowed to reduce weight so that the teeth and supporting tissues are not stressed unnecessarily. The conventional open design drains fluid from the adjacent mucosa, possibly increasing the weight of the prosthesis, and is difficult to clean. The closed bulb design does not drain secretions and may cause obstruction and susceptibility to infection in the paranasal and pharyngeal regions, though it is easier to maintain. An alternative to the two designs, combining their advantages, is presented in this report. As the open hollow part of the obturator was shallow, it was easy to clean. Making the inferior part of the bulb hollow and closed led to a reduction in the overall weight of the prosthesis while increasing its resonance.

Placement of implants in an ossifying fibroma defect obliterated with demineralized, freeze-dried bone allograft and Plasma-rich growth factor

There has been considerable clinical interest in combining the grafts, particularly bone allografts for support for dental implants, soft-tissue support, periodontal maintenance, and ovate pontic formation. The use of demineralized, freeze-dried bone allograft (DFDBA) offers certain advantages over other graft materials and can avoid the need for a second-site surgery for autogenous donor bone. The advantages of DFDBA include handling properties, osteoinductivity, membrane tenting, and less susceptibility to migration after placement. This article will review available grafting materials and demonstrate a case of ossifying fibroma of the mandible, which was treated by curettage and hollow cavity filled with DFDBA. Six months follow-up period showed successful graft result and this grafted bone form was utilized for implant supported prosthesis.

Comparison of the effectiveness of Tokuyama and GC II metal primer on the bond strength of acrylic resins to Ti-6Al-7Nb

Statement of Problem: Because of the toxicity of vanadium in Ti-6Al-4V alloy, next generation of titanium alloys is proposed to focus on niobium-containing alloy, but for clinical applications, it is crucial for this alloy to bond with acrylic resins with or without the use of primers. However, literature was lacking about the effect of primers on bonding of autopolymerizing resins to Ti-6Al-7Nb. Objectives: To evaluate the effect of different metal primers on the shear bond strength of acrylic resin to Ti-6Al-7Nb. Materials and Methods: A total of 30 dis-shaped wax patterns (10 mm in diameter and 2 mm thickness) were prepared and casted using Ti-6Al-7Nb. After casting, the disk surfaces were finished with abrasive paper under water. Specimens were equally divided into three groups on the basis of the use of primer: metal primer (GC II metal primer) (Group 1), Universal Tokuyama primer (Group 2), no primer (Group 3). Tape of 50 μm thickness was applied on each of the specimens. Then, self-cure acrylic resin was mixed and applied on the center part of the tape, on which Bernouilles tube was placed. The tensile bond strength was measured with a universal testing machine. The data were obtained for all the specimens and analyzed using Statistical Package for Social Sciences version 17.0 at a statistically significance level of <0.05. Results: Mean tensile force was maximum for Group 2 (28.58 ± 39.40 N) and minimum for control Group 3 (6.24 ± 10.97 N), thereby showing a significant inter-group difference (P < 0.001). On applying post hoc test (Tukey HSD), both the Group 1 and Group 2 showed a statistically significant difference as compared to control Group 3; however, the difference between two experimental groups was not statistically significant (P > 0.05). Conclusions: Tokuyama primer and GC II metal primer had a significant effect on improving the bond strength between autopolymerizing denture base resin and Ti-6Al-7Nb.

Comparison of Rehabilitating Missing Mandibular First Molars with Implant‐ or Tooth‐Supported Prostheses Using Masticatory Efficiency and Patient Satisfaction Outcomes

PURPOSE To determine whether a fixed partial denture (FPD) or an implant replacement of a single missing tooth leads to better masticatory efficiency and patient satisfaction. MATERIALS AND METHODS One-hundred and twenty participants with missing mandibular right first molars were selected on the basis of predefined inclusion and exclusion criteria. After obtaining informed consent, 60 participants were randomized to the teeth-supported (FPD) group and 60 to the implant placement group (IMP). The study was divided into the following parts: (i) Completion of a Likert scale satisfaction questionnaire (postrehabilitation) by the participants. (ii) Evaluation of masticatory efficiency and performance 3 months after rehabilitation. Data were evaluated by applying t-test and z-test using statistical analysis (α ˂ 0.05). RESULTS Masticatory efficiency of participants in the IMP and FPD groups was 74.95 ± 0.90% and 74.41 ± 3.35%, respectively (p = 0.607). Total satisfaction questionnaire scores for the two groups were also not significantly different; however, the mean scores of overall satisfaction and function categories in this questionnaire were significantly higher for the IMP group, while the mean score for the duration of treatment question was higher for the FPD group (p < 0.05). CONCLUSION The results of this study suggested that although masticatory performance and efficiency were not statistically different for single teeth replaced with implants or FPDs, patients perceived higher satisfaction with implant restorations; they also preferred the shorter treatment times for rehabilitation in the FPD group.

An In Vivo 24-Month Study to Compare Crestal Bone Loss and Pocket Depth of Platform-Switched Implants Placed in Maxillary Anterior and Mandibular Posterior Regions.

PURPOSE To analyze and compare crestal bone loss and pocket depth around platform-switched implants placed at two intraoral locations. MATERIALS AND METHODS Eighty platform-switched implants, 40 in the maxillary anterior region (group - ANT) and 40 in the mandibular posterior region (group - POST), were placed in healthy men aged between 25 and 45 years, and restored following two-stage surgical and progressive loading protocols. Digital radiographs for crestal bone level assessment and pocket depths on facial, mesial, distal, and palatal/lingual sites around the implant were recorded at definitive restoration cementation (baseline) and 6-month follow-up. Difference in pre- and post-periodontal pocket depths and crestal bone loss levels were measured and analyzed statistically using SPSS v.16.0, applying the Mann-Whitney test (p < 0.05 considered significant). RESULTS Mean bone loss was significantly higher in group ANT (1.2 ± 0.3 mm) than in group POST (0.7 ± 0.02 mm). Palatal pocket depth increase was significantly greater in the ANT group (p = 0.01), and distal pocket depth increase was significantly greater for the POST group (p = 0.002). CONCLUSION The amount of bone loss noted in the maxillary anterior region compared to the mandibular posterior region was significantly more. This could possibly be because of greater vertical cantilever and offset loads in the anterior compared to the posterior region. Significantly greater pocket depth in mandibular posterior distal and maxillary anterior palatal regions could be related to oral hygiene maintenance issues.