Evaluation of the Co-Go-Me angle as a predictor in Class II patients treated with Herbst appliance and skeletal anchorage: a retrospective cohort study.

Introduction: A condylion-gonion-menton (Co-Go-Me) angle threshold of 125.5° has been introduced as a predictive parameter of cephalometric mandibular response in the orthopedic treatment of growing Class II patients with functional appliances, despite some contradictions in the literature. Considering the lack of studies evaluating the role of skeletal anchorage, this study aims to reassess the threshold of 125.5° in the Co-Go-Me angle as a useful predictor in growing skeletal Class II patients treated with acrylic splint Herbst appliance and two mini-screws in the lower arch (STM2). Methods: Thirty-five consecutively treated patients (20 males, 15 females; mean age, 11.37 years) with mandibular retrusion were classified into two groups according to their Co-Go-Me baseline values (Group 1, <125.5°; Group 2, >125.5°). The STM2 protocol involved the use of the MTH Herbst appliance with an acrylic splint in the lower arch and two interradicular mini-screws as anchorage reinforcement. Cephalometric analysis was performed by the same operator for each patient at baseline (T0) and at the end of the Herbst phase (T1). The effects of time and group on the variables were assessed by a repeated-measures analysis of variance. The primary research outcome was the difference between the groups in terms of mandibular responsiveness to treatment referred to as the relative difference (T1-T0) in Co_Gn. Results: The mean duration of the treatment was 9.5 months. No statistically significant differences between groups were detected at baseline, except from the expected SN/GoMe° (p < 0.001) and Co-Go mm (p = 0.028). No statistically significant changes between groups, which were caused by the treatment, were found considering the mandibular sagittal and vertical skeletal parameters. Similarly, no statistically significant differences were found in the dental changes between the high-angle and low-angle patients, apart from the upper molar sagittal position (p = 0.013). Discussion and conclusions: The 125.5° threshold in the Co-Go-Me value was not a reliable predictive parameter for the mandibular response in growing patients treated with the MTH Herbst appliance and lower skeletal anchorage. Due to its effective control in the sagittal and vertical planes, the STM2 technique might be an appropriate protocol to use in treating skeletal Class II patients, regardless of the growth pattern.

Is significant mandibular advancement possible after the peak of puberty? Dento-osseous palatal expansion and the STM4 technique (Skeletal Therapy Manni Telescopic Herbst 4 miniscrews): A case report.

INTRODUCTION: Treatment of skeletal class II growing patients often requires the use of functional appliances, aimed at promoting mandibular advancement. Among these, Herbst appliance is recommended for its effectiveness, efficiency, and reduced need for compliance. Despite its skeletal favourable effects, well-known dental compensations can occur, especially when the appliance is not used close to the pubertal peak: upper incisors retroclination, lower incisors proclination, upper molars distalization and lower molars mesialization could reduce the overjet needed for a proper mandibular advancement. To counteract these unfavourable effects skeletal anchorage could be crucial. AIM: The aim of this case report is to describe and evaluate the effects of using a skeletally anchored Herbst appliance in an 18-year-old (CVM5) male patient with skeletal Class II malocclusion and a convex profile. TREATMENT PROTOCOL: The treatment started with a tooth-bone-borne palatal expansion, then the upper arch was bonded with pre-adjusted ceramic brackets. After 2months, a Manni Telescopic Herbst (MTH) supported by 4 miniscrews (two in the maxilla and two in the mandible) was applied. To avoid anchorage loss, TADs were connected with elastic chains to the arches. Nine months later, the Herbst was removed, the lower teeth were bonded and the patient wore class 2 elastics to stabilise the occlusion. RESULTS AND CONCLUSIONS: After 24months the treatment goal was achieved with a considerable improvement of the profile and a clinically significant mandibular advancement (Pogonion moved forward 7mm). A one-year follow-up lateral X-rays showed a good stability of the result.

Two different designs of mini-screw assisted maxillary expanders, using FEM to analyse stress distribution in craniofacial structures and anchor teeth.

OBJECTIVE: The objective of this study was to analyse the displacement, strain, and stress distribution of various craniofacial structures after applying maxillary expansion with two different bone-borne Haas-inspired miniscrew-assisted maxillary expander (BB HIMAME) and bone-tooth-borne miniscrew-assisted rapid palatal expander (BTB MARPE) using three-dimensional finite element analysis (3D FEA). MATERIAL AND METHODS: two expanders including bone-anchored maxillary expander and bone tooth-borne were designed to simulate expansion in a 3D FEA. Expanders were activated transversely for 0.2mm. The stress distribution and displacement of various craniofacial structures and anchor teeth were calculated. RESULTS: The finding showed that the amount of stress in all sutures was greater in BB than BTB expander. The greatest stress was induced in the fronto-maxillary suture in the BB expander, which was 4.45MPa. While it was 0.7MPa in BTB. Anchor tooth showed tipping movement in BTB expander, although the crown and apex of the anchor tooth moved in the same direction with BB device. CONCLUSIONS: It is recommended that the BB expander is used when bodily movement of anchor tooth is needed. BTB may serve as an effective modality for cases with low-quality bone conditions. BTB appliance creates some extent of tipping on anchor teeth.

"Surgery First" vs "Traditional Sequence" Surgery: A Qualitative Study of Health Experiences in 46 Bimaxillary Orthognathic Patients.

Introduction: Orthognathic patients are advocating an active role in selecting their appropriate ortho-surgical treatment, between the surgery first (SF) and the traditional sequence (TS) approaches. The aim of this study was to evaluate, through qualitative analysis, the subjective perceptions of the outcomes of each protocol. Methods: In-depth interviews were conducted with 46 (10 male and 36 female) orthognathic patients (23 SF and 23 TS) treated with bimaxillary orthognathic surgery by the same surgeon, between 2013 and 2015. Average treatment duration was 6.5 months for SF and 12 months for TS. Inclusion criteria were: the presence of Class III or Class II asymmetries and open bite. Patients were excluded if they refused interviews or stopped attending post-treatment follow-up. Investigated health experiences included overall satisfaction with appearance, self-confidence after surgery, perceived treatment time, functional recovery, and diet restrictions. Results: All SF and TS patients showed overall satisfaction with their appearance (though TS showed more enthusiastic tones) and approved their degree of functional recovery after surgery. Class III SF patients had earlier improvements in self-confidence after surgery. Orthodontics was considered enduring by both SF and TS patients. Conclusions: SF patients expressed a higher degree of satisfaction with the reduction in overall treatment time and with the early psychological benefit deriving therefrom. Both SF and TS patients completely approved of the aesthetic outcomes and the functional recovery from which they benefitted due to the entire procedure.

Vertical maxillary excess associated with altered passive eruption: a case report with an interdisciplinary approach.

A smile is a symbol of beauty and wellbeing in our modern society, human facial expression transcending language, culture, race, gender, time, and socioeconomic differences. An esthetic smile consists of three main components: the teeth, the lip framework, and the gingival scaffold. In some patients, the altered relationship between the teeth, the alveolar bone, and the soft tissue may result in the clinical condition known as gummy smile. A single factor or a combination of factors may be present in patients with this clinical condition, including altered passive eruption (APE), vertical maxillary excess, and a short or hyperactive upper lip. The present article reports on a 31-year-old female patient who presented for a consultation. The patient, who was in good general health with no significant medical history, was dissatisfied with her tooth esthetics. She had symmetric facial features with a long face appearance, retruded chin, protruded maxillary incisors, and excessive gingival display that indicated evident APE. In particular, the present case report aims to describe a multidisciplinary treatment involving a phase of orthodontics associated with maxillofacial surgery, and the periodontal surgical sequence of esthetic crown lengthening for the treatment of APE.

Influence of incisor position control on the mandibular response in growing patients with skeletal Class II malocclusion.

INTRODUCTION: This study aimed to test whether control in maxillary and mandibular incisor position, during treatment with an acrylic splint Herbst appliance, could influence the mandibular response in growing patients with skeletal Class II malocclusion. METHODS: The lateral cephalograms of 61 patients (mean age, 12.3 years; standard deviation, 1.6) with skeletal and dental Class II malocclusion were retrospectively analyzed both at baseline and after Herbst appliance removal, using a modified Pancherz cephalomeric analysis. Forty-five patients had received miniscrew in the mandibular arch to control mandibular incisor anchorage. In 21 patients, the maxillary incisors had been proclinated before starting the treatment for deepbite and maxillary incisor lingual inclination. All the patients were categorized a posteriori into 2 homogeneous groups, according to dental overjet reduction: 30 patients with dental overjet reduction (DR) and 31 patients without dental overjet reduction (NDR). RESULTS: Both groups presented a significant skeletal correction. However, the change was significantly greater in the NDR group than in the DR group (P <0.01). The mandibular bone base reached a median value of 4.0 mm (interquartile range, 2.5) in the NDR group vs 1.1 mm (interquartile range, 2.8) in the DR group (P <0.001). The 2 groups were also significantly different in terms of the positional change of maxillary incisor, which was proclinated in group NDR and lingualized in group DR (P <0.001). CONCLUSIONS: The results showed that dental control of overjet was beneficial to improve the effectiveness of Herbst treatment in increasing mandibular length in growing patients with skeletal Class II malocclusion.

A New Proposal: a Digital Flow for the Construction of a Haas-Inspired Rapid Maxillary Expander (HIRME).

Maxillary expansion is a common orthodontic treatment used for the correction of posterior crossbite resulting from reduced maxillary width. Transverse maxillomandibular discrepancies are a major cause of several malocclusions and may be corrected in different manners; in particular, the rapid maxillary expansion (RME) performed in the early mixed dentition has now become a routine procedure in orthodontic practice. The aim of this study is to propose a procedure that reduces the patient cooperation as well as the lab work required in preparing a customized Haas-inspired rapid maxillary expander (HIRME) that can be anchored to deciduous teeth and can be utilized in mixed dentition with tubes on the molars and hooks and brackets on the canines. This article thus presents an expander that is completely digitally developed, from the first moment of taking the impression with an optical scanner to the final solidification phase by the use of a 3D printer. This digital flow takes place in a CAD environment and it starts with the creation of the appliance on the optical impression; this design is then exported as an stl extension and is sent to the print service to obtain a solid model of the device through a laser sintering process. This "rough" device goes through a post-processing procedure; finally, a commercial expansion screw is laser-welded. This expander has all the advantages of a cast-metal Haas-type RME that rests on deciduous teeth; moreover, it has the characteristic of being developed with a completely digitized and individualized process, for the mouth of the young patient, as well as being made completely of cobalt-chrome, thus ensuring greater adaptability and stability in the patient's mouth.

The ideal insertion angle after immediate loading in Jeil, Storm, and Thunder miniscrews: A 3D-FEM study.

OBJECTIVE: The miniscrew is effectively used to provide additional anchorage for orthodontic purposes. The aim of this study was to identify an optimal insertion angle for Jeil, Storm, and Thunder miniscrews on stress distribution at the bone miniscrew interface. MATERIALS AND METHODS: To perform 3-dimensional finite element model analysis, a 3-dimensional model with a bone block was constructed with type D2 of bone quality, and with miniscrews of Storm, Thunder, Jeil, with the diameter of 2, 1.5. 1.6mm and length 15.9, 12.4, 14.4mm respectively. The miniscrews were inserted at 15° 30°, 45°, 60°, 75° and 90° to the bone surface. A simulated horizontal orthodontic force of 200 gram was applied to the centre of the miniscrews head in all models, and stress distribution and its magnitude were evaluated with a 3-dimensional finite element analysis program. RESULTS: In the cancellous bone, minimum stress was found at placement angles of 90° for Jeil and Storm, which was 0.37 and 0.39MPa respectively, and 15° for Thunder, which was 0.85MPa. The maximum von Mises stresses in the cancellous bone for Jeil was at 60°, which was 0.92MPa, and for Thunder at 90°, which was 1.3MPa. CONCLUSION: Each miniscrew has an ideal insertion angle, optimal insertion positions were found within 90° for Jeil and for Storm but 15° for Thunder. Clinical significance 3-dimensional finite element analysis confirmed that each miniscrew has an ideal insertion angle according to its characteristics.

The effect of Alexander, Gianelly, Roth, and MBT bracket systems on anterior retraction: a 3-dimensional finite element study.

OBJECTIVES: The aims of this study were to compare the effect of 4 bracket systems including Alexander, Roth, MBT, and Gianelly on upper anterior retraction and to quantify the amount of torque loss ratio in sliding mechanics by help of a 3-dimensional (3D) finite element method. METHOD AND MATERIALS: 3D FEM models were constructed in order to simulate anterior incisor retraction in first premolar extraction case. Displacement, stress, and strain on the incisal edge and apex of maxillary central incisor were calculated when 1-, 2-, and 3-N retraction forces were applied. Torque loss ratio was calculated by measuring the displacement of the teeth at crown tip and root apex in all 4 bracket systems on upper central incisor. RESULTS: Uncontrolled lingual crown tipping of the incisor was observed in all bracket systems. The crown moved lingually by 9.5 µm and the root labially by 4.5 µm in MBT system with 3-N retraction force. The amount of crown movement was 8 µm and the root displacement was 4 µm in Gianelly system with the same retraction force. Torque loss ratio was 1.46 in Alexander and Gianelly with 3-N retraction force. However, the amount of torque loss ratio was 1.47 in MBT and Roth with the same retraction force. CONCLUSIONS AND CLINICAL RELEVANCE: Uncontrolled tipping was the least in Gianelly and was the highest in MBT. The amount of torque loss ratio was the lowest in Gianelly and Alexander systems and the amount of torque loss ratio was the highest in MBT system.

Four TADs supported Herbst mechanics: A case report.

The Herbst appliance (HA) is considered an efficient method to treat class II malocclusion characterized by mandibular retrusion. Nevertheless, HA is although hampered by side effects reducing its therapeutic potentialities. The association between HA and TADs in the lower arch has proved to be very effective in controlling lower incisor flaring. This case report shows that the insertion of TADs in both arches offers a satisfactory control of the vertical dimension, by avoiding a maxillary clockwise inclination.

3-dimensional finite element analysis of the outcomes of Alexander, Gianelly, Roth and MBT bracket prescription.

The purpose of this study was to compare the effect of a 4-bracket system including Alexander, Roth, MBT (Maxillary Transverse Bioadaptation), and Gianelly on the upper anterior tooth movement in sliding mechanics with the help of a 3-Dimensional (3D) Finite Element Method. METHODS: Displacement, stress, strain, centre of rotation and resistance on the incise edge and apex of the maxillary central incisor were calculated when 100, 200, 300, 400grams of retraction force were applied. RESULTS: The amount of incise edge displacement was 2.609×10-4mm 2.682×10-4mm 2.875×10-4mm and 2.881×10-4mm in Alexander, Gianelly, Roth and MBT respectively with 100gr of retraction force. The value of apex root movement was 3.485×10-4mm 3.547×10-4mm 3.852×10-4mm and 3.864×10-4mm in Alexander, Gianelly, Roth and MBT respectively with 400g of retraction force. CONCLUSIONS: The MBT system had the maximum apex root and incisal edge movement in all 100, 200, 300, 400grams of retraction force. The Alexander system had the lowest apex and incisal edge movement in all retraction forces.