Orthodontic Anchorage Procedures

Humans ; Orthodontic Anchorage Procedures ; Orthodontics, Corrective

Just like other subjects in medicine, orthodontics also uses some vague concepts to describe what are difficult to measure quantitatively. Anchorage control is one of them. With the development of evidence-based medicine, orthodontists pay more and more attention to the accuracy of the clinical evidence. The empirical description of anchorage control is showing inadequacy in modern orthodontics. This essay, based on author's recent series of studies on anchorage control, points out the inaccuracy of maximum anchorage concept, commonly neglected points in quantitative measurement of anchorage loss and the solutions. It also discusses the limitation of maximum anchorage control.
Bone Screws ; Humans ; Orthodontic Anchorage Procedures ; Orthodontics

Humans ; Orthodontic Anchorage Procedures ; Orthodontic Brackets ; Orthodontics, Corrective ; methods

OBJECTIVES: This study was performed to evaluate patterns of failure time after insertion, failure rate according to loading time after insertion, and the patterns of failure after loading. MATERIALS AND METHODS: A total of 331 mini-implants were classified into the non-failure group (NFG) and failure group (FG), which was divided into failed group before loading (FGB) and failed group after loading (FGA). Orthodontic force was applied to both the NFG and FGA. Failed mini-implants after insertion, ratio of FGA to NFG according to loading time after insertion, and failed mini-implants according to failed time after loading were analyzed. RESULTS: Percentages of failed mini-implants after insertion were 15.79%, 36.84%, 12.28%, and 10.53% at 4, 8, 12, and 16 weeks, respectively. Mini-implant failure demonstrated a peak from 4 to 5 weeks after insertion. The failure rates according to loading time after insertion were 13.56%, 8.97%, 11.32%, and 5.00% at 4, 8, 12, and 16 weeks, respectively. Percentages of failed mini-implants after loading were 13.79%, 24.14%, 20.69%, and 6.9% at 4, 8, 12, and 16 weeks, respectively. CONCLUSION: Mini-implant stability is typically acquired 12 to 16 weeks after insertion, and immediate loading can cause failure of the mini-implant. Failure after loading was observed during the first 12 weeks.
Dental Implants ; Immediate Dental Implant Loading ; Orthodontic Anchorage Procedures

After tooth has been removed for a long time, adjacent teeth may tilt to occupy the edentulous space, leading to a break in the occlusal 3D equilibrium and a lack of restorative space. This case report presents a mandibular second molar uprighting with anchorage from a dental implant.
Dental Implants ; Molar ; Orthodontic Anchorage Procedures ; Tooth Movement Techniques

Adult ; Dental Implantation, Endosseous ; instrumentation ; Dental Implants ; Female ; Humans ; Orthodontic Anchorage Procedures ; instrumentation ; Orthodontic Appliance Design

PURPOSE: This study was performed to investigate the bone thickness of the infrazygomatic crest area by computed tomography (CT) for placement of a miniplate as skeletal anchorage for maxillary protraction in skeletal Class III children. MATERIALS AND METHODS: CT images of skeletal Class III children (7 boys, 9 girls, mean age: 11.4 years) were taken parallel to the Frankfurt horizontal plane. The bone thickness of the infrazygomatic crest area was measured at 35 locations on the right and left sides, perpendicular to the bone surface. RESULTS: The bone was thickest (5.0 mm) in the upper zygomatic bone and thinnest (1.1 mm) in the anterior wall of the maxillary sinus. Generally, there was a tendency for the bone to be thicker at the superior and lateral area of the zygomatic process of the maxilla. There was no clinically significant difference in bone thickness between the right and left sides; however, it was thicker in male than in female subjects. CONCLUSION: In the infrazygomatic crest area, the superior and lateral area of the zygomatic process of the maxilla had the most appropriate thickness for placement of a miniplate in growing skeletal Class III children with a retruded maxilla.
Child ; Female ; Humans ; Male ; Maxilla ; Maxillary Sinus ; Orthodontic Anchorage Procedures ; Zygoma

A growing number of studies have reported that mini-implants do not remain in exactly the same position during treatment, although they remain stable. The aim of this review was to collect data regarding primary displacement immediately straight after loading and secondary displacement over time. A systematic review was performed to investigate primary and secondary displacement. The amount and type of displacement were recorded. A total of 27 studies were included. Sixteen in vitro studies or studies using finite element analysis addressed primary displacement, and nine clinical studies and two animal studies addressed secondary displacement. Significant primary displacement was detected (6.4-24.4 µm) for relevant orthodontic forces (0.5-2.5 N). The mean secondary displacement ranged from 0 to 2.7 mm for entire mini-implants. The maximum values for each clinical study ranged from 1.0 to 4.1 mm for the head, 1.0 to 1.5 for the body and 1.0 to 1.92 mm for the tail part. The most frequent type of movement was controlled tipping or bodily movement. Primary displacement did not reach a clinically significant level. However, clinicians can expect relevant secondary displacement in the direction of force. Consequently, decentralized insertion within the inter-radicular space, away from force direction, might be favourable. More evidence is needed to provide quantitative recommendations.
Dental Implants ; Humans ; Miniaturization ; Orthodontic Anchorage Procedures ; instrumentation ; methods ; Stress, Mechanical

OBJECTIVEThis study aims to biomechanically analyze a mini-implant at different healing times before loading.

METHODSSixty-four mini-implants with (12 +/- 1) N x cm insertion torque were placed in the low jaw of eight beagle dogs. The test mini-implants remained in the low jaw for 0, 1, 3, and 8 weeks of bone healing and for an additional 10 weeks under a force of 0.98 N. The unloaded control implants were further divided into four groups (1, 3, 8, and 10 weeks). Maximum removal torque (MRT) testing was performed to evaluate the interfacial share strength of each group. Surface analysis of the removed implants was performed by scanning electric microscope (SEM).

RESULTSThe MRT for the loading implants at 0, 1, 3, and 8 weeks of healing were 4.10, 4.25, 2.42, and 4.42 N x cm, respectively. During the healing process, the removal torque values of the 3-week implants were significantly lower than those of the other healing groups (P < 0.05). The unloaded 3-week implants also had lower removal torques (P < 0.05). The implant surface of the 3-week test group showed more fibrous bone. However, the other loading implants had more lamellar-like tissue.

CONCLUSIONA stable dangerous period occurred approximately 3 weeks after mini-implant insertion. A 3-week healing is disadvantageous to the stability of the implant. Orthodontics loading occurred immediately or after 1 week as a function of the healing time. The 8-week implant appeared to have a positive effect on peri-implant bone remodeling and implant stability.