Primary failure rate for 1680 extra-alveolar mandibular buccal shelf mini-screws placed in movable mucosa or attached gingiva

Chang, Chris H.; Liu, Sean S.-Y.; Roberts, W. Eugene

doi:10.2319/092714.695.1

Cited by 122 publications

(97 citation statements)

References 37 publications

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“…17 With the latter method, there was no significant difference in the success rate for >1600 MBS bone screws, placed in either attached gingiva or moveable mucosa. Unfortunately, there are no CBCT records for the other case reports reviewed (n=16), so they cannot be analyzed with the current FEA method.…”

Section: Discussionmentioning

confidence: 99%

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion

Roberts

Viecilli

Chang³

et al. 2015

American Journal of Orthodontics and Dentofacial Orthopedics

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Introduction: In the absence of adequate animal or in vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning and retrospective analysis. The hypothesis tested is that instantaneous FEA can approximately predict long-term, mandibular occlusal plane rotation to plan the correction of a skeletal Class III malocclusion. Methods: Seventeen published case reports were selected for patients treated with statically determinate mechanics, utilizing posterior mandible (PM) or infrazygomatic crest (IZC) bone screw anchorage, to retract the lower arch. Twodimensional (2D) measurements were made for incisor and molar movement, lower arch rotation, and retraction relative to the upper arch. A patient with cone-beam computed tomography (CBCT) imaging was selected for a retrospective finite element analysis (FEA). Results: The mean age (+SD) for the sample was 23.3±3.3 years; seven were male and 10 were female. Mean incisor movement was 3.35±1.55mm of retraction and 2.18±2.51mm of extrusion. Corresponding molar movement was retraction of 4.85±1.78mm and intrusion of 0.85±2.22mm. Retraction of the lower arch relative to the upper arch was 4.88±1.41mm. Mean posterior rotation of the lower arch was -5.76±4.77° (counterclockwise). The mean treatment time (n=16) was 36.2±15.3 mo. Bone screws in the PM region were more efficient for intruding molars and decreasing the vertical dimension of occlusion (VDO) to close an open bite. The fullcusp, skeletal Class III patient selected for FEA was treated to an ABO CRE score of 24 points in ~36mo by en masse retraction and posterior rotation of the mandibular arch: the bilateral load on the lower segment ~200cN. The lower arch was retracted ~5mm, posterior rotation was ~16.5°, and molar intrusion was ~3mm. There was a 4° decrease in the mandibular plane angle (MPA) to close the skeletal openbite. Retrospective sequential iterations (FEA animation) simulated the clinical response, as documented with longitudinal cephalometrics. The level of PDL stress was relatively uniform (<5kPa) for all teeth in the lower arch segment. Conclusions: En masse retraction of the lower arch is efficient for conservatively treating skeletal Class III malocclusion. PM anchorage results in intrusion of molars to close the VDO and MPA. Instantaneous FEA as modeled here could be used to reasonably predict the clinical results of an applied load.

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Section: Discussionmentioning

confidence: 99%

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion

Roberts

Viecilli

Chang³

et al. 2015

American Journal of Orthodontics and Dentofacial Orthopedics

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“…Different sites have been used for mini-screw insertion: palatal bone, 7,8 the palatal side of the maxillary alveolar process, 9 the mandibular retromolar area, 10 the infrazygomatic crest, 11 the maxillary and mandibular bucco alveolar cortical plate, 12 and the posterior palatal alveolar process. 7 Recently, the mandibular buccal shelf (MBS) has been proposed 13 as a suitable extra-alveolar mini-screw insertion site. The MBS is located bilaterally in the posterior part of the mandibular body, buccal to the roots of the first and second molars and anterior to the oblique line of the mandibular ramus.…”

Section: Introductionmentioning

confidence: 99%

Bone and cortical bone thickness of mandibular buccal shelf for mini-screw insertion in adults

Nucera

Giudice

Bellocchio

et al. 2017

The Angle Orthodontist

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Specific sites of the MBS offer enough bone quantity and adequate bone quality for mini-screw insertion. The insertion site with the optimal anatomic characteristics is the buccal bone corresponding to the distal root of second molar, with screw insertion 4 mm buccal to the cementoenamel junction. Considering the cortical bone thickness of optimal insertion sites, pre-drilling is always recommended in order to avoid high insertion torque.

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“…It comprises a thicker cortical bone of approximately 3 mm, which makes it suitable for mini‐implant placement without a risk of inferior alveolar nerve damage. Chang et al [14] reported a high success rate (of approximately 93%) at the extra‐alveolar mandibular buccal shelf, but no significant difference was observed between placement in the movable mucosa or the attached gingiva. Therefore, this study designed an artificial bone with 3 mm and 40 pcf cortical bone and 20 pcf cellular bone marrow.…”

Section: Discussionmentioning

confidence: 99%

Effects of gripping volume in the mechanical strengths of orthodontic mini‐implant

Tseng

Chen

et al. 2017

The Kaohsiung J of Med Scie

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The objective of study was to investigate the correlation between the mechanical strengths [insertion torque (IT); resonance frequency (RF); and horizontal pullout strength (HPS)] and gripping volume (GV) of mini-implants. Thirty mini-implants of three types (Type A: 2 mm × 10 mm, cylindrical, titanium alloy; Type B: 2 mm × 10 mm, tapered, stainless steel; and Type C: 2 mm × 11 mm, cylindrical, titanium alloy) were inserted 7 mm into artificial bones. One-way analysis of variance and Spearman's test were applied to assess intergroup comparisons and intragroup correlations. The null hypothesis was that no statistically significant correlations exist between the GV and mechanical strengths (IT, RF, and HPS). In the IT test, Type C (14.2 Ncm) had significantly (p=0.016) greater values than did Type A (12.4 Ncm). In the RF analysis, no significant difference was observed among the three types of mini-implants. In the HPS test, Type C (388.9 Ncm) was significantly larger than both Type B (294.5 Ncm) and Type A (286 Ncm). In the GV measurement, Type C (14.4 mm) was significantly larger than Type B (11.4 mm) and Type A (9.2 mm). Type A and Type B exhibited no significant correlations among the tests. Therefore, the null hypothesis was accepted. Although no significant correlation was noted between the GV and mechanical strengths (IT, RF, and HPS), we observed a trend that the mechanical strengths (IT, RF, and HPS) of the mini-implants corresponded to the order and values of GV (Type C > Type B > Type A).

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Primary failure rate for 1680 extra-alveolar mandibular buccal shelf mini-screws placed in movable mucosa or attached gingiva

Cited by 122 publications

References 37 publications

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion

Biology of biomechanics: Finite element analysis of a statically determinate system to rotate the occlusal plane for correction of a skeletal Class III open-bite malocclusion

Bone and cortical bone thickness of mandibular buccal shelf for mini-screw insertion in adults

Effects of gripping volume in the mechanical strengths of orthodontic mini‐implant

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