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: Cortical bone thickness is one of the important factor in mini-implant stability. This study was performed to investigate the buccal cortical bone thickness at every interdental area as an aid in planning mini-implant placement. MATERIALS AND METHODS: Two-dimensional slices at every interdental area were selected from the cone-beam computed tomography scans of 20 patients in third decade. Buccal cortical bone thickness was measured at 2, 4, and 6 mm levels from the alveolar crest in the interdental bones of posterior regions of both jaws using the plot profile function of Ez3D2009trade mark (Vatech, Yongin, Korea). The results were analyzed using by Mann-Whitney test. RESULTS: Buccal cortical bone was thicker in the mandible than in the maxilla. The thickness increased with further distance from the alveolar crest in the maxilla and with coming from the posterior to anterior region in the mandible (p<0.01). The maximum CT value showed an increasing tendency with further distance from the alveolar crest and with coming from posterior to anterior region in both jaws. CONCLUSION: Interdental buccal cortical bone thickness varied in both jaws, however our study showed a distinct tendency. We expect that these results could be helpful for the selection and preparation of mini-implant sites.
Cone-Beam Computed Tomography ; Humans ; Jaw ; Mandible ; Maxilla ; Orthodontic Anchorage Procedures

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

OBJECTIVEThis study aims to compare the treatment outcomes in patients with maxillary dentoalveolar protrusion by applying different anchorage methods via three-dimensional model measurement.

METHODSA total of 46 patients with maxillary dentoalveolar protrusion treated with bilateral maxillary first premolar extractions and high anchorage were selected. The subjects were randomly divided into three groups according to the type of anchorage applied, which included implant, extraoral, and Nance arch anchorages. The maxillary dental models were made before treatment and after space closure of maxilla. The movements of the maxillary central incisors and first molars were measured via a three-dimensional model measurement, and the amounts of movement were compared among the three groups.

RESULTSThe sagittal lingual movements of the maxillary central incisors were (-6.661 ± 1.328), (-5.939 ± 1.806), and (-5.788 ± 2.009) mm for the implant, extraoral, and Nance arch anchorage groups, respectively, with no significant difference among the three groups (P = 0.121). The corresponding vertical movements of the maxillary central incisors were (0.129 ± 1.815) mm intrusion, and (-2.162 ± 2.026), (-2.623 ± 1.776) mm extrusion. Significant difference was found between the implant anchorage group and the other groups (P < 0.05). The corresponding sagittal mesial movements of the maxillary first molars were (0.608 ± 1.045), (1.445 ± 1.462), and (1.503 ± 0.945) mm. The corresponding vertical movements of the maxillary first molars were (0.720 ± 0.805) mm intrusion, (0.076 ± 0.986) mm intrusion, and (-0.072 ± 0.690) mm extrusion. Significant difference was found between the implant anchorage group and the other two groups (P < 0.05). In the transverse direction, the first molars all moved lingually with no significant difference among the three groups (P > 0.05).

CONCLUSIONImplant anchorage may be superior in the vertical control of the maxillary incisors and in the sagittal, as well as in the vertical control of the maxillary molars, compared with the traditional anchorages during the treatment of patients with maxillary dentoalveolar protrusion.