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BACKGROUND: Deep bite is a common characteristic of malocclusion, and many methods are used to treat it, including mini-implants used for the intrusion of the upper incisors. Orthodontically induced inflammatory root resorption (OIIRR) is an inevitable and unexpected side effect of orthodontic therapy. However, resorption of the root could be affected by the type of tooth movement, such as intrusion. Several studies have indicated the effectiveness of low-level laser therapy (LLLT) in accelerating orthodontic movement, but studies that have evaluated the role of this laser in reducing the risk of OIIRR have been limited. This trial aimed to investigate the effectiveness of LLLT in reducing the resorption of the roots of the upper incisors during their intrusion in the context of deep bite correction. MATERIALS AND METHODS: Thirty patients (13 males, 17 females; mean age 22.4±3.37 years) with deep overbite were recruited and allocated to the laser or the control groups. Mini-implants were inserted between the roots of the upper central incisors and the lateral incisors from the labial aspect at the gingival-mucosal junction on both sides with a force of 40 g on each side through an NiTi coil spring. A low-level laser (Ga-Al-As) with 808 nm wavelength in a continuous mode, with the parameters 250 milliwatt power output, 4 Joules/point energy density, and 16 seconds irradiation per point, was applied to the root of each of the upper incisors. The laser was applied on the first day of the upper incisor intrusion (T1), then on days 3, 7, and 14 of the first month. In the second month, the laser was applied every 15 days, adjusting the spring strength every four weeks until the end of the intrusion stage (T2), which was determined by reaching a normal overbite. As for patients in the control group, the strength of the nickel-titanium springs was adjusted every four weeks to the required strength of 40 g on each end until reaching a normal overbite. RESULTS: There was a volumetric decrease in both groups' upper central and lateral incisors roots, and this decrease was statistically significant (P<0.001). However, the difference between the two groups was not statistically significant in each central and lateral incisor volume root (P=0.345 and 0.263 for U1 and U2, respectively). Also, both groups had a linear decrease in upper central and lateral incisors roots, which was statistically significant (P<0.001). At the same time, the difference between the two groups was not statistically significant in each central and lateral incisor root length (P=0.343 and 0.461 for U1 and U2, respectively). CONCLUSION: The low-level laser irradiation using the current protocol did not significantly affect the amount of root resorption induced by incisor intrusion in the experimental group compared to the control group.

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This case report demonstrates an innovative technique involving concomitant correction of a traumatic extrusive luxated tooth, the mobility of which was being aggravated by anterior occlusal contacts, along with transverse rapid maxillary expansion to capitalize on the advantage of residual growth and simplify the need for comprehensive fixed orthodontic appliance. By incorporating a molar tube into the acrylic splint of the bonded Hyrax expander adjacent to the buccal surfaces and parallel to the buccal cusps of the maxillary first molars, effective intrusion of traumatically extruded upper incisor was achieved concomitantly using a modified intrusion arch during the passive stabilization period after expansion, thereby reducing treatment time. This enabled the immediate correction of extruded tooth and reduced the overall treatment duration and the complexity of post-expansion fixed mechanotherapy, improving compliance and uplifting the self-esteem of the patient. The modified bonded Hyrax assembly can serve as a versatile interim appliance for the simultaneous management of a variety of orthodontic problems such as crowding, spacing, and incisor proclination without compromising the basic integrity of the bonded assembly.

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OBJECTIVES: To compare the cephalometric treatment results of adult deep-bite cases after labial and lingual fixed orthodontic treatment. MATERIALS AND METHODS: A total of 102 patients underwent lingual orthodontic treatment and complete records were evaluated. The following inclusion criteria were used: patients who had Angle Class I or mild Class II malocclusion; comprehensive orthodontic treatment that did not include intrusion mechanics or any extractions; patients with an initial overbite of more than 3.7 mm. Thirteen patients met the inclusion criteria. These cases were matched with the same number of patients according to age with a labial orthodontic treatment group. Pre- and post-treatment cephalometric radiographs were evaluated. Independent t test or Fisher exact tests were performed to assess the differences between the groups. RESULTS: Proclination of the upper incisors was higher in the labial group. Incisor mandibular plane angle (IMPA) showed an increase of 1.2° in the lingual group and 9.7° in the labial group. Lower incisor edge was approximately in a stable sagittal position in the lingual group but significant lower incisor proclination was seen in the labial group. The lower incisors were intruded (-1 mm) in the lingual group but lower incisors were minimally extruded (0.3 mm) in the labial group. No significant difference was found in the movements of upper and lower molars for both groups. CONCLUSIONS: The nature of lower incisor movement involved less protrusion in lingual orthodontics than the labial treatment. Lingual orthodontic treatment is a better option in adult cases where intrusion of lower incisors without labial tipping is desired.

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BACKGROUND: Miniscrews are effective devices for performing upper incisor intrusion. Different mechanics can be applied depending on the treatment objectives. This study aimed to evaluate the efficacy of one or two anterior miniscrews for upper incisor correction in cases of overbite and angulation in adult patients. METHODS: Forty-four adults with deep overbite were divided into two groups: group 1 was treated with one miniscrew between upper central incisors and group 2 with two miniscrews between upper lateral incisors and canines. Incisor intrusion and length were measured from lateral cephalograms before treatment, after treatment and at least 12 months into retention (T0, T1 and T2). Forces were applied (90 g) from the miniscrews to the archwire using elastomeric chains. ANOVA analysis was used to determine whether differences between evaluation times were statistically significant. RESULTS: Mean root resorption was 2.15 ± 0.85 mm, which ceased after active treatment. Overbite mean correction was - 3.23 ± 1.73 mm with no statistically significant relapse. Overbite correction and incisor intrusion were significantly greater in group 2 (- 3.80 ± 1.43 versus - 2.75 ± 1.63 for OB and 8.19 ± 3.66 versus 5.69 ± 2.66 for intrusion). Resorption and overbite correction were positively related. No counterclockwise rotation of the mandibular plane was observed. CONCLUSIONS: Overbite correction can be performed by means of upper incisor intrusion without rotation of the mandibular plane. Correction of upper incisor intrusion and overbite is greater in patients treated with two miniscrews. The increase in upper incisor buccal angulation is greater with one miniscrew. Root resorption is positively related to the extent of intrusion. Stability is satisfactory regardless of whether one or two miniscrews are used.

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This case report shows a successful orthodontic treatment of an operated adult bilateral cleft lip and palate subject with short upper lip and excessive incisor display. The patient underwent cleft lip repair at an early age of 2.5 years, followed by palatoplasty at the age of 21 years. She presented with malaligned teeth, inability to close the lips, excessive upper incisor display, and difficulty in speech. She was treated with upper and lower arch alignment and intrusion of the upper incisors, followed by prosthetic replacement of the missing right lateral incisor and left lateral incisor and canine. Normal dental occlusion was achieved using orthodontic procedures, followed by prosthodontic rehabilitation that resulted in significant improvement in facial aesthetics and psychosocial benefit to the individual.

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The treatment of skeletal deep bite does not remain stable. The patient was a Japanese woman aged 16 years and 10 months. Her chief complaint was maxillary protrusion. The degree of overjet was + 10.5 mm and overbite was + 5.0 mm; the intermolar relationship was Angle Class II. An excessive curve of Spee was observed in the mandibular arch. A hypodivergent skeletal pattern was indicated by a small mandibular plane angle and gonial angle. The maxillary incisors were proclined and the mandibular incisors were retroclined. Based on the above findings, the patient was diagnosed with Angle Class II maxillary protrusion and deep bite with hypodivergency. Both maxillary first premolars were extracted and orthodontic treatment was performed using multi-bracket appliances. A proper overbite was achieved by 5.0 mm intrusion of the mandibular incisors. The maxillary incisors were retracted by 11.2 mm and a proper overjet was achieved. Good treatment results were obtained without apical root resorption. After 2 years of retention, the occlusion has been well maintained. This report may constitute a remarkable suggestion for treatment of an unstable deep bite.

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OBJECTIVE: To compare, through cone-beam computed tomography (CBCT), the root resorption and treatment efficiency of two different mini-implant-assisted modalities in intruding the maxillary incisors. MATERIALS AND METHODS: Thirty-two adults who had deep bite and elongated maxillary incisors were randomly allocated to two groups: anterior mini-implant group (AMG) and posterior mini-implant group (PMG). In the AMG, approximately 40 g of force was applied per side with elastic chains from mini-implants placed between the lateral incisors and canines and in the PMG, with beta-titanium wires from mini-implants placed between the second premolars and first molars. This study was conducted on CBCT scans taken before intrusion and after 4 months of intrusion. Data were analyzed by means of a paired t-test, independent t-test, and Pearson's correlation test. RESULTS: One patient was excluded from the AMG due to mini-implant loosening. While the incisors showed a significant reduction in length and volume, this amount was greater in the AMG, especially in the central incisors (P < .05). Together with the mean intrusion rates of 0.62 and 0.39 mm/mo in the AMG and PMG respectively, the center of resistance of the incisors showed distal movement with labial tipping; these changes were greater in the PMG (P < .001). Volumetric root resorption was correlated with the amount of intrusion (P < .05). CONCLUSIONS: Intrusion anchoring from posterior mini-implants is preferred in cases of upright incisors, as the use of such mechanics directs the roots into the spongiosa where they undergo less root resorption and more labial tipping.

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BACKGROUND: Intrusion of maxillary incisors is one of the most important and difficult tooth movements to achieve as a part of orthodontic therapy. A variety of techniques were used in the past to intrude the maxillary incisors before the emergence of mini implants in Orthodontics. Mini implants are temporary anchorage devices used to produce various tooth movements. The research was carried out to evaluate and compare the efficiency of producing intrusion of maxillary incisors using mini implants, utility arch and j- hook headgear. MATERIALS AND METHODS: The study was conducted on 30 subjects divided into 3 Groups equally. Group 1- mini implant anchorage, Group 2 - j- hooks headgear and Group 3- utility arch were used for intrusion of the maxillary incisors. Conventional lateral cephalograms were taken before treatment and at the end of intrusion. Five cephalometric parameters were used to measure the amount of intrusion attained in each Group. Intra Group comparisons were done using student t-test and inter Group comparisons were done using ANOVA The duration of intrusion was four months in all the three Groups. RESULTS: In Group 1 the mean average intrusion attained was 2.1 mm, the mean average intrusion attained in Group 2 was 0.7 mm, and the mean average intrusion achieved in Group 3 was 1.4 mm with a side effect of 0.75 mm of molar extrusion. CONCLUSION: Although, both mini implants and utility arch can be used to attain significant amounts of incisor intrusion but using mini implants will produce true intrusion without any other side effects.

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OBJECTIVE: This study aimed to propose clinical guidelines for placing miniscrew implants using the results obtained from 3-dimensional analysis of maxillary anterior interdental alveolar bone by cone-beam computed tomography (CBCT). METHODS: By using CBCT data from 52 adult patients (17 men and 35 women; mean age, 27.9 years), alveolar bone were measured in 3 regions: between the maxillary central incisors (U1-U1), between the maxillary central incisor and maxillary lateral incisor (U1-U2), and between the maxillary lateral incisor and the canine (U2-U3). Cortical bone thickness, labio-palatal thickness, and interdental root distance were measured at 4 mm, 6 mm, and 8 mm apical to the interdental cementoenamel junction (ICEJ). RESULTS: The cortical bone thickness significantly increased from the U1-U1 region to the U2-U3 region (p < 0.05). The labio-palatal thickness was significantly less in the U1-U1 region (p < 0.05), and the interdental root distance was significantly less in the U1-U2 region (p < 0.05). CONCLUSIONS: The results of this study suggest that the interdental root regions U2-U3 and U1-U1 are the best sites for placing miniscrew implants into maxillary anterior alveolar bone.

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OBJECTIVE: This study aimed to propose clinical guidelines for placing miniscrew implants using the results obtained from 3-dimensional analysis of maxillary anterior interdental alveolar bone by cone-beam computed tomography (CBCT). METHODS: By using CBCT data from 52 adult patients (17 men and 35 women; mean age, 27.9 years), alveolar bone were measured in 3 regions: between the maxillary central incisors (U1-U1), between the maxillary central incisor and maxillary lateral incisor (U1-U2), and between the maxillary lateral incisor and the canine (U2-U3). Cortical bone thickness, labio-palatal thickness, and interdental root distance were measured at 4 mm, 6 mm, and 8 mm apical to the interdental cementoenamel junction (ICEJ). RESULTS: The cortical bone thickness significantly increased from the U1-U1 region to the U2-U3 region (p < 0.05). The labio-palatal thickness was significantly less in the U1-U1 region (p < 0.05), and the interdental root distance was significantly less in the U1-U2 region (p < 0.05). CONCLUSIONS: The results of this study suggest that the interdental root regions U2-U3 and U1-U1 are the best sites for placing miniscrew implants into maxillary anterior alveolar bone.

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This study was designed to investigate the position of anteroposterior center of resistance for genuine intrusion and the mode of change of the minimum distal force for simultanous intrusion and retraction of the upper and lower incisors according to the increase of labial inclination. For this purpose, we used the three-piece intrusion arch appliance and three-dimensional finite element models of upper and lower incisors. 1. Positions of the center of resistance in upper incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 6mm behind the distal surface of the lateral incisor bracket. 2) In 10degrees increase of the labial inclination situation, the center of resistance was located in 9mm behind the distal surface of the lateral incisor bracket. 3) In 20degrees increase of the labial inclination situation, the center of resistance was located in 12m behind the distal surface of the lateral incisor bracket. 4) In 30degrees increase of the labial inclination situation, the center of resistance was located in 16m behind the distal surface of the lateral incisor bracket. 2. Positions of the center of resistance in lower incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 10mm behind the distal surface of the lateral incisor bracket. 2) In 10degrees increase of the labial inclination situation, the center of resistance was located in 13mm behind the distal surface of the lateral incisor bracket. 3) In 20degrees increase of the labial inclination situation, the center of resistance was located in 15m behind the distal surface of the lateral incisor bracket. 4) In 30degrees increase of the labial inclination situation, the center of resistance was located in 18m behind the distal surface of the lateral incisor bracket. 3. The patterns of stress distribution were as follows; 1) There were even compressive stresses in and periodontal ligament when intrusion force was applied through determined center of resistance. 2) There were gradual increase of complexity in compressive stress distribution pattern with increase of the labial inclination when intrusion and retraction force were applied simultaneously.

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