ABSTRACT
Objective: To evaluate and compare the effect of variation in storage temperatures and duration on a tensile load at failure of elastomeric modules. Methods: In total, 140 modules were used in the study, 20 of which were tested on day 0 as received from a company using a Universal testing machine for baseline estimation of tensile load at failure. The rest 120 modules were divided into 6 groups. Groups I, II, and III modules were stored at low (T1 = 1–5°C), moderate (T2 = 20–25°C) and high (T3 = 35–40°C) temperatures, respectively, for 6 months. Groups IV, V and VI modules were stored at temperatures T1, T2 and T3 for 1 year, respectively, and were tested for tensile load at failure. Results: The tensile load at failure for the control group was 21.588 ± 1.082 N and for 6?month interval at temperatures T1, T2 and T3 was 18.818 N ± 1.121 N, 17.841 N ± 1.334 N and 17.149 N ± 1.074 N, respectively, and for 1 year, it was 17.205 N ± 1.043 N, 16.836 N ± 0.487 N and 14.788 N ± 0.781 N, respectively. The tensile load at failure decreased significantly from 6 months to 1 year among each temperature group. Conclusions: Maximum force degradation was seen in modules at high temperature followed by medium temperature and low temperature at both 6 months and 1 year intervals, and tensile load at failure decreased significantly from 6 months to 1 year storage duration. These results conclude that the temperature and duration at which the samples were exposed during storage produce a significant change in the forces exerted by the modules.
ABSTRACT
Diagnosis and treatment planning in skeletal discrepancy and disorders requires radiographic assessment. Disturbance in growth and development alters the morphologic build-up of bony structures, which makes evaluation difficult. Out of these skeletal landmarks Point ANS is seen affected in many conditions like cleft lip and palate, Binders Syndrome, Down’s Syndrome, nasomaxillary hypoplasia, etc., wherein maxilla is mostly affected. Surgical intervention if required needs exact evaluation of point ANS. The purpose of the present study is thus to revisit Point ANS to aid in the cephalometric evaluation in cases where location of Point ANS is difficult; thus, making treatment planning easy. METHODS50 lateral cephalograms were evaluated by taking reference of skeletal landmarks and linear measurements were done. RESULTSLinear measurements from Point Ptm’-Ba’, Ba’-ANS’, ANS’-A were found to be proportionally equal with a ratio of 1:1:1. CONCLUSIONSLinear distance of Point ANS to N perpendicular (ANS’) line was approximately half of the linear distance of Point Ba’-A, while Point ANS is placed approximately 5±2 mm ahead of the line N perpendicular.
ABSTRACT
Management of patients with congenitally missing mandibular second premolars continues to challenge clinicians to find the best treatment options. The Orthodontist must make the proper decision at the appropriate time regarding management of the edentulous space. If space is left for an eventual prosthetic replacement, the clinician should try to create the exact amount of space required and leave the alveolar ridge in an ideal condition for the future restoration. If the space is to be closed orthodontically, detrimental changes to the occlusion and facial profile must be prevented. Therefore, the correct decision must be made at the appropriate time. This paper presents a case report of a congenitally missing lower left second premolar where molar protraction with orthodontic temporary anchorage device has been done.
ABSTRACT
Mandibular distraction osteogenesis has become a popular surgical modality due to its many advantages over conventional orthognathic surgical procedures. However, in spite of the technique having been used for over 15 years, no concrete long term results are available regarding the stability of results. We discuss the various studies which have reported either in favour or against the stablility of results after distraction. We report a series of 6 cases (3 unilateral and 3 bilateral distraction) where distraction was carried out before puberty and followed them up to seven years after removal of distractors. This case series shows that results achieved by distraction osteogenesis are unstable or best unpredictable with respect to producing a permanent size increase in the mandible. The role of the distraction osteogenesis in overcoming the pterygomassetric sling is questionable. We suggest a multicenter study with adequate patient numbers treated with a similar protocol and documented after growth cessation to have meaningful conclusions on the debate of distraction osteogenesis versus orthognathic surgery.