Influence of Implant Location, Number, and Design in Ischemic Zone for Implant Prosthesis Success Rate: A Comparative Three-Dimensional Finite Element Analysis.

BACKGROUND: The performance of an implant-supported prosthesis depends on the implant type, number, implant location, and prosthesis design which is directly associated with the distribution of the occlusal forces during mastication. The purpose of the present study is to analyze with three-dimensional (3D) finite element comparative analysis, the influence of implant location, number, and prosthesis design in the mandibular posterior region where multiple posterior teeth replacement is indicated, which in turn is associated with the longevity or Implant success rate. MATERIAL AND METHODS: Mandibular posterior section, where 4 teeth are missing, based on the space available for implants and following the surgical guide instructions, a standard make four implants (1st and 2nd premolars {3.8 mm × 11.5 mm}, 1st and 2nd molar {5.1 mm × 11.5 mm}) were selected and with standardization for placement, 4 groups were created with different implant location, number and prosthesis design from the selected implants as model FM1, FM2, FM3, FM4. Finite element analysis was carried out using ANSYS software, version 14.5 (ANSYS Inc., Canonsburg, PA, USA) for assessment of stress, strain, and deformation around implant and bone. RESULTS: Maximum von Mises stress on vertical loading was highest for FM4 (139.55MPa) model (center of prosthesis on premolar and molar pontics) and lowest for FM3 (53.65MPa) model (on 2nd premolar pontic) with values in decreasing order as FM4 ˃ FM2 ˃ FM1 ˃ FM3. Maximum von Mises stress on oblique loading was highest at the distal of 1st molar implant pontic for FM2 (539.81MPa) and lowest at the 2nd premolar pontic for FM3 (352.48MPa) model with values as FM2˃FM1˃FM4˃FM3. Deformation for vertical and oblique loading was observed minimum at the buccal cusp and buccal crestal bone of 2nd premolar, 1st molar on FM3 model against highest deformation on buccal and lingual crestal bone, cuspal area of 2nd premolar, 1st molar implants. For oblique loading minimum deformation was seen for the 2nd premolar, 1st molar cuspal area in FM3, and maximum at the 2nd premolar region in FM1. CONCLUSION: Four single implants may be chosen if there is enough mesiodistal and buccolingual space to allow for a minimum inter-implant and inter-implant-tooth distance that can be maintained while putting the least amount of stress on the implants and bone. To reduce stress on the bone and implants, it is best to avoid long-span implant-supported prostheses when using fixed implant-supported prostheses.

The aberrant extraction of a maxillary canine and two lower incisors.

Extractions are a common place in orthodontics. The present article discusses a rare case, in which a left maxillary canine along with two lower incisors was extracted. Atypical extractions such as these need to be duly justified and thought over before being carried out. In the case mentioned, all these teeth in question were ectopically erupted. When attempts were made to retract the canine in its right position, it exhibited gingival recession which would only go on increasing further as the distance from the transposed position in between the left central and lateral incisor to the original position was considerably large. It was planned that the 1st premolar would be converted to canine on completion of the treatment. The lower incisors too would have shown severe periodontal damage had attempts to align them was made. Not only were these two teeth lingually erupted but they also were rotated along their long axis. Derotation along with labial movement would have caused breakage of the supracrestal and transseptal fibers resulting in periodontal breakdown leading to mobility of these teeth. An esthetically and functionally balanced outcome was achieved following these extractions. In the upper arch, although the midline remained compromised, it was not worsened. In the lower arch alignment was achieved with preservation of the intercanine width. Complicated cases such as these require a thorough scrutiny of all available options. Whatever the treatment plan may be, the ultimate goal of functional and esthetic balance should be achieved.

Early manifestation of mild cognitive impairment in B-cell non-Hodgkin's lymphoma patients receiving CHOP and rituximab-CHOP chemotherapy.

Existing evidence suggests that pro-inflammatory cytokines increases during chemotherapy which plays an intermediary role in Chemotherapy related cognitive impairment (CRCI) and thyroid dysregulation. Previous studies suggest that thyroid hormones are essential for neuronal development and neurotransmitter release. CHOP regimen has been the backbone of Non-Hodgkin's lymphoma (NHL) treatment from a decade but rituximab addition to CHOP (R-CHOP) has improved cure rates. However, their adverse event profile on behavior is not well studied on patients. In this study total 68 NHL patients were enrolled and divided equally in 2 groups as CHOP receiving (n = 34) and R-CHOP receiving (n = 34). Effects of R-CHOP and CHOP regimen on thyroid function, pro-inflammatory cytokines and cognitive function were determined at four time points that was from one day before 1st (TP0), 2nd (TP1), 3rd (TP2) and 4th (TP3) cycle of chemotherapy. Results indicated significant increase in levels of pro-inflammatory cytokines after each time point from TP0 to TP3of chemotherapy. Thyroid hormone levels i.e. T3, T4 were found significantly decreased and TSH was increased after each time point of both groups. MMSE score was found significantly decreased after each cycle of both groups. However, an inverse association was found between IL-1ß levels with TSH by applying correlation coefficient. Cognitive function was decreased in patients with decreased T3 and T4 levels and increased TSH. To conclude, patients receiving R-CHOP regimen were found to have more increased IL-6 and IL-1ß with more cognitive decline and thyroid abnormality as comparison to CHOP receiving patients.

Assessment of stability of orthodontic mini-implants under orthodontic loading: A computed tomography study.

OBJECTIVES: Miniscrews have been used in recent years for anchorage in orthodontic treatment. However, it is not clear whether the miniscrews are absolutely stationary or move when force is applied. This prospective clinical study was undertaken to evaluate the mobility of orthodontic miniscrews under orthodontic loading using computed tomography. MATERIALS AND METHODS: Ten adult patients (7 females and 3 males with mean age of 19 years, 7 mm overjet) who required en masse retraction of upper and lower anterior teeth infirst premolar extraction spaces were included in this study. After initial alignment of anterior teeth, the 0.019" ×0.025" stainless steel archwire were placed in preadjusted edgewise appliance. The miniscrews (diameter - 1.3 mm, length - 7 mm) were inserted in between second premolar and thefirst molar in the maxilla (zygomatic buttress) and in mandible on the buccal side as direct anchorage. Immediately after placement of miniscrews without waiting period, NiTi coil springs (force of 150 g in the maxilla and 100 g in the mandible) were placed for the retraction. Denta Scans were taken immediately before force application (T1) and 6 months later (T2). The mean changes obtained at T1 and T2 in Denta Scans (axial plane, coronal plane, paraxial plane) were evaluated to determine any movement of different parts of miniscrews using one-way ANOVA test and Student's unpaired t-test. RESULTS: On average, miniscrews were extruded and tipped forward significantly, by 1 mm at the screw head in the axial plane (Group III) and 0.728 mm in the coronal plane (Group IV). Tail of miniscrews showed average tipping of 0.567 mm in the axial plane (Group I) and 0.486 mm in the paraxial plane (Group V). Least average mobility was shown by screw body of 0.349 mm in the axial plane (Group II). Clinically, no significant mobility was observed. CONCLUSION: Miniscrews are a stable anchorage for orthodontic tooth movement but do not remain absolutely stationary like an endosseous implant throughout orthodontic loading although miniscrews might move according to placement site, orthodontic loading, and inflammation of peri-implant tissue. Waiting period between miniscrews placement and orthodontic loading does not significantly affect the miniscrew mobility so immediate loading can be recommended. To prevent hitting any vital organs because of miniscrew mobility, it is recommended that they can be placed in a nontooth-bearing area that has no foramen, major nerves, or blood vessel pathway, or in a tooth-bearing area allowing a 1.5 mm safety clearance between the miniscrew and dental root.

Clinical review of sitagliptin: a DPP-4 inhibitor.

Type 2 Diabetes Mellitus is most common form of diabetes. Oral agents are the main stay of pharmacological treatment for type 2 diabetes mellitus. Dipeptidyl peptidase-4 (DPP-4) inhibitors represent a new therapeutic approach for type 2 diabetes. Sitagliptin is highly selective DPP-4 inhibitor that has been approved for type 2 diabetes therapy. It acts by increasing the levels of incretins by inhibiting their degradation by DPP-4. Sitagliptin has been shown to be effective, well tolerated and safe in the treatment of type 2 diabetes in monotherapy or in combination with metformin or thiozolidinediones with minimal side effects.