An in vitro study of factors affecting the primary stability of orthodontic mini-implants

Holm, Lindsy; Cunningham, Susan; Petrie, Aviva; Cousley, Richard

doi:10.2319/011912-47.1

Cited by 41 publications

(22 citation statements)

References 22 publications

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“…Recent studies show success rates for single minicrews ranging from 57% (17) to 93.43% (7). Failure is defined as loss of primary (18)(19)(20)(21) or secondary (19) stability during treatment. A low failure rate leads to limitations in statistical analyses, which generally have low statistical power.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Factors Associated with Orthodontic Microscrew Failure

Dobranszki

Faber

Scatolino³

et al. 2014

Braz. Dent. J.

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The objective of this study was to examine whether factors such as insertion site, patient's facial pattern, microscrew features, type of tooth movement desired, level of experience handling orthodontic microscrews and operator expertise were associated with failure of microscrews. After the approval of an ethics committee, 166 patients of one practice signed an informed consent and received 293 microscrews randomly distributed by 3 operators with different levels of practical experience and expertise in handling microscrews. The microscrews were observed in a period of 365 days or as long as orthodontic forces had to be applied and independent variables were recorded. Analysis by the chi-square test did not produce enough evidence as to allow the assertion that there was an association between the variable "failure" and the variables "maxilla" (p=0.4775), "face" (p=0.1081), "facial pattern" (p=0.7522), "microscrew length" (p=0.9113), "desired movement" (p=0.0584), and "operator" (p=0.5785). The variable "insertion side" was significantly associated with "failure" (p=0.0022). In a 365-day survival analysis, the Log Rank test yielded a p-value of 0.00178 for the curve of variable "insertion side," and showed no significant differences for other variables. With a total success rate of 87.38%, the only variable found to be significant was "insertion side" (p=0.0022), with 3.088 more likelihood of a microscrew failing if placed on the left side than on the right side. The procedure of inserting microscrews involved a rapid learning curve for an inexperienced operator, which justifies their placement by orthodontists.

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Section: Discussionmentioning

confidence: 99%

Analysis of Factors Associated with Orthodontic Microscrew Failure

Dobranszki

Faber

Scatolino³

et al. 2014

Braz. Dent. J.

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“…Other studies focus on macroscopic design elements such as thread and taper design [8]. Different lengths and diameters as well as conical or cylindric shapes were tested for their influence on primary stability [9,10]. Most of these investigations are in-vitro studies.…”

Section: Introductionmentioning

confidence: 99%

Impact of mini-implant length on stability at the initial healing period: a controlled clinical study

Nienkemper

Wilmes

Pauls³

et al. 2013

Head Face Med

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IntroductionAim of the study was to assess the impact of the length of mini-implants inserted in the midpalatal region on the stability at the initial healing period.MethodsA sample of 20 consecutively treated patients (15.6 ± 7.2 years) was examined. A long mini-implant with a length of 11 mm and a diameter of 2 mm was inserted into the anterior palate of each patient. Resonance frequency analysis (RFA) was performed after insertion (T0), two weeks (T1), four weeks (T2), and six weeks (T3). Insertion depth (ID) and the maximum insertion torque (IT) were measured. RFA, ID and IT data were tested for correlations. RFA values were tested for statistical differences between the different times. Data was compared to a matched control group of patients who received short mini-implants with a length of 9 mm and a diameter of 2 mm.ResultsMean ID was 9.5 ± 0.6 mm and mean IT was 17.9 ± 3.8 Ncm. A correlation was found between RFA and ID (r = 0.59, P < .01). From T0 to T1 the stability (33.4 ± 3.5 ISQ) decreased highly significantly by 5.3 ± 3.5 ISQ values (P < .001) and significantly from T1 and T2 (P < .05) by 3.5 ± 3.7 ISQ values. From T2 on RFA nearly remained unchanged (−1.7 ± 3.9 ISQ; P > .05). At T1 stability was significantly lower than the control group. From T2 on there were no significant differences between the groups.ConclusionsLong mini-implants provide high stability when inserted in the midpalatal region. After initial decrease RFA values remained stable from four weeks on and did not differ from the control group.Trial registrationID: 2013081293 (Clinical study register, University of Düsseldorf, Germany).

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“…25 The mean MIT of the N2 reached as high as 19.3 Ncm in 40 pcf cortical bone density, exceeding the physiological limit of 14.65 Ncm. 22 Evidently, the N2 is not ideal for insertion into areas of very high bone density.…”

Section: 23mentioning

confidence: 99%

Mechanical stability and clinical applicability assessment of novel orthodontic mini-implant design

Song¹,

Hong

Banh

et al. 2013

The Angle Orthodontist

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Objective: To compare the stability and clinical applicability of a novel orthodontic mini-implant design (N2) with the most widely used commercially available (CA) design. Materials and Methods: Two groups of mini-implants were tested: a CA design (1.5-mm diameter, 6-mm length) and N2 (3-mm diameter, 2-mm length, tapered shape). Implants were inserted in bone blocks of cortical bone simulation with varying densities (20 pounds per cubic foot [pcf], 30 pcf, and 40 pcf). A torque test was used to measure maximum insertion torque (MIT) and maximum removal torque (MRT). Compression and tension force vectors were applied at angles of 10u, 20u, 30u, and 40u using customized load pins to determine primary stability. Results: Mean MIT and MRT were higher in the N2 than the CA design at all three cortical bone densities except MRT in 20 pcf bone (not statistically significant). The mean compression force required to displace the N2 at all distances and angulations was greater for the N2 than the CA design. At all displacement distances, the highest mean tension force required for N2 displacement was at 10u angulation, whereas at 30u and 40u, the mean tension force required to displace the CA design was greater. Conclusions: The primary stability of the N2 is superior to that of the CA design and is promising for both orthodontic and orthopedic clinical applicability, especially under compression force. The short length of the N2 reduces risk of damage to anatomic structures and root proximity during placement and orthodontic treatment. The stability of the N2 may be compromised in areas of high bone density and highly angulated tension force. (Angle Orthod. 2013;83:832-841.)

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An in vitro study of factors affecting the primary stability of orthodontic mini-implants

Cited by 41 publications

References 22 publications

Analysis of Factors Associated with Orthodontic Microscrew Failure

Analysis of Factors Associated with Orthodontic Microscrew Failure

Impact of mini-implant length on stability at the initial healing period: a controlled clinical study

Mechanical stability and clinical applicability assessment of novel orthodontic mini-implant design

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