Introduction:The design of an appliance for retraction of six anterior teeth using orthodontic mini-implant (OMI) anchorage and sliding mechanics must take into account the position and height of the mini-implant and the height of the anterior retraction hook, we used finite element analysis to examine effective en masse retraction with orthodontic mini-implant anchorage and sought to identify a better combination of the above factors.Materials and methods: Base models were constructed from a measurements given in the Wheeler's dental anatomy book. The center of resistance for the 6 anterior teeth in the base model was calculated. The working archwires were assumed to be 0.019" × 0.025" in stainless steel. The amount of tooth displacement after finite element analysis was measured. Results and conclusions:In low OMI (6 mm) anteriors showed tipping movement. Mid implant condition (8 mm) showed more of bodily movement during retraction as the force passes near or through the CRs of all the six anterior teeth. In high OMI (10 mm) and 0 mm ARH condition, all the six anterior teeth showed intrusion with retraction.

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IntRoductIon One of the major challenges in orthodontics is to achieve an excellent result with appliances that are both esthetic and comfortable. There is currently enormous interest in so-called "invisible orthodontics." The increasing demand for an esthetic appearance among adult orthodontic patients, even during orthodontic treatment period, has led to the advent of invisible orthodontic treatment. Tooth-colored brackets and archwires, clear aligner therapy, and lingual orthodontic treatment are the invisible way of treating the malocclusion so far available. However, these brackets and archwires are invisible from a certain distance only. Furthermore, the clear aligners are not purely invisible as it is a transparent sheet closely adapted to the teeth. The lingual orthodontic appliances are, in a true sense, the only invisible appliance system available. [1] The art and science of lingual orthodontics depends on choice of bracket system, laboratory procedure, wire form, and mechanics during initial leveling/aligning and retraction.

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Currently, mini-implants have become the boon for anchorage in orthodontics because of their many advantages such as ease of insertion and removal, small size, and patient compliance. The site of implant placement is a prime consideration because of risk of injury to root of teeth, especially when inserted between teeth. Placement of implant at improper position can result in improper bone support and stability when mini-implants are loaded. Therefore, it is important to select insertion site by clinical and radiographic evaluation. Many techniques have been introduced to facilitate the mini-implant placement but requires more time for guide fabrication or inconsistent in radiographic interpretation. This article shows a new implant placement guide which is easy to fabricate, less time-consuming, reliable, and more accurate for implant insertion.

OBJECTIVE: To evaluate the changes in surface morphology of two different types of mini-implants after clinical en masse retraction using scanning electron microscopy. MATERIAL AND METHODS: Fifty mini-implants of Dentos (Korea, Absoanchor, BH-1817-08) and Orlus (Korea, Yesanchor, C-1817) were inserted in patients in a split-mouth design who required en masse anterior retraction and absolute anchorage. Surface characteristics of mini-implants such as pitch (distance between consecutive threads), flank width (distance between root and crest), and taper were studied using scanning electron microscope (FEI nanosem450) before and after clinical use. RESULTS: Statistically significant difference (p value = 0.003) was found in a mean reduction of pitch dimension among the two groups with a mean difference of 25.000 μm. Also, a statistically significant difference was noted (p value = 0.001) in a mean reduction of flank width among Dentos implants as compared to Orlus implants. A statistically significant difference (p = 0.001) was seen in the mean reduction of taper dimension among Dentos group (0.0140 ± 0.02271) as compared to the Orlus group (0.0810 ± 0.05152). CONCLUSION: A marked reduction in surface morphology such as the pitch, flank width, and taper of both mini-implants after retrieval was observed. Dentos group of mini-implants displayed better dimensional stability post-retrieval as compared to the Orlus group of mini-implants. All the mini-screws showed milling defects in form of scratches on observation under scanning electron microscopy despite a smooth appearance to the naked eye.

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