Palatal Bar Research Articles

Forced orthodontic extrusion for an apparently hopeless anterior tooth by using a simplified approach

When restoring severely compromised teeth, respecting the supracrestal tissue attachment and retaining the most coronal and radicular tooth structure is essential to achieving a sufficient ferrule. Forced orthodontic extrusion is a minimally invasive method that allows hard- and soft-tissue conservation. This article describes the treatment of a severely damaged maxillary central incisor that was managed by using a simplified orthodontic extrusion method with intracoronal elastic and metal ligatures applied through a palatal bar and followed by the biologically oriented preparation technique (BOPT). This orthodontic procedure reduces a forward clockwise advance during vertical extrusion, thus maintaining the buccal bone plate.

Influence of the position of the palatal bar on brain activity during speech

Influence of the position of the palatal bar on brain activity during speech

弾力のある可動域をもった軟口蓋挙上装置（モバイル軟口蓋挙上装置Fujishima type）の考案と使用経験

弾力のある可動域をもった軟口蓋挙上装置（モバイル軟口蓋挙上装置Fujishima type）の考案と使用経験

Role of transpalatal vault fixation with 2.0 plate for transverse palatal expansion in segmental le fort osteotomy

Background: Segmental Le Fort I osteotomy is a predictable, well-established surgical technique that is commonly used to correct maxillary transverse discrepancies up to 6–7 mm in adults. However, transverse expansion of the maxilla with a segmental Le Fort I osteotomy is often associated with postsurgical instability and relapse. Different methods have been recommended to reduce the potential for transverse instability involving bone grafts or allografts at the palatal osteotomy site, use of palatal bars and expanders, interocclusal splints and transpalatal bone-anchored devices. However, transverse maxillary expansion with a segmental Le Fort I osteotomy is still considered the least stable surgical orthognathic procedure and overexpansion with stable fication method frequently recommended.

Influence of the position of the palatal bar on brain activity during swallowing

Influence of the position of the palatal bar on brain activity during swallowing

EVALUATION OF ADAPTATION AND STRESS INDUCED BY DIFFERENT DESIGNS OF PALATAL MAJOR CONNECTORS

The purpose of this in-vitro study was to evaluate adaptation and stresses induced over the abutment teeth and residual ridge through different designs of maxillary major connectors.Materials and methods: An acrylic resin model was fabricated and three different designs of upper major connectors were constructed, the first design was anterior palatal strap, the second design was anterior palatal bar and the third design was anterior-posterior palatal strap. Stress analysis was evaluated using strain gauge and strain developed was recorded. The adaptation was measured by Leica Micro System LTd, made in Germany. Data were calculated, tabulated and analyzed using statistical ANOVA test to compare between the last 10 readings obtained from the different designs when unilaterally and bilaterally loaded. Data were presented as mean and standard deviation (SD) values. Results: The results revealed that the stresses transmitted to the abutments teeth and residual ridge by the anterior palatal bar major connector was of lower values than those recorded when the anteroposterior and anterior palatal strap were used. Regarding the adaptation of the major connectors no significant differences occurred before or after loading.Conclusion: It can be concluded that much higher stresses transmitted by the anteroposterior palatal strap and the anterior palatal strap than that transmitted by the anterior palatal bar. Future research should focus on the minimal dimensions for relevant major connectors’ adaptation.

19 上顎第一大臼歯に対するパラタルバーの嚥下時における影響 (第445回 大阪歯科学会例会)

19 上顎第一大臼歯に対するパラタルバーの嚥下時における影響 (第445回 大阪歯科学会例会)

Dental and skeletal changes after intra-oral molar distalization using a “Distal Driver” appliance: a pilot study

Introduction. Loss of space in the maxillary arch is a frequent consequence of early loss of deciduous molars indicating distalisation of the mesialised molar tooth. A number of methods using either extra-oral appliances or intra oral appliances of various types have been suggested. While extra-oral appliances exert a high but intermittent force many of the intraoral ones deliver a modest, though constant, force and demands no patient cooperation. Aim of study. To investigate the effect of an intra-oral fixed appliance (Distal Driver) based on a NiTi spring incorporating also a standardised anchorage unit on the position of the maxillary first molar as well as on the facial skeleton and the dentition in general. Material and methods. The experimental group comprised 6 child patients exhibiting a distal molar relationship (Unilateral or Bilateral) of at least ½ premolar unit. The mesialised molars were distalised by means of a “Distal driver” exerting a force of 150 gm for a period of 3-4 weeks. Anchorage was created by a fixed modified palatal bar cemented on the premolars supporting an acrylic palatal button ad modum Nance. The clinical situation was recorded before and after molar distalisation by means of study casts, cephalograms, panoramic radiographs as well as intra-oral photographs. The distalisation of the molars as well as the effect on anchorage teeth was quantitated on digital models derived from the plaster casts. Evaluation of the observed distal and vertical changes in molar position was performed on the lateral cephalogram. Results. Cast analysis showed a clear distalising effect on the maxillary first molars ranging from 1.25 mm to 6.18 mm as well as mesial movement of the premolar anchorage teeth from 0.46 mm to 5.55mm. The cephalometric analysis revealed a first molar distalisation of 0.9 mm to 5.6 mm though again with a mesial movement of the first premolar varying from 0.5 mm to 3.7 mm. A clear distal tipping of the first and second molars simultaneously with a mesial tipping of the first premolars was also recorded. Conclusion. The Distal Driver constitutes an efficient method of maxillary molar distalisation though is often accompanied by a distal rotation of these teeth and a mesial tipping of the anchorage premolars. Careful monitoring of anchorage loss is necessary if good results are to be achieved.

Effects of Reinforcement on Denture Strain in Maxillary Implant Overdentures: An In Vitro Study Under Various Implant Configurations.

Maxillary implant overdentures are often designed without palatal coverage to maximize wearer comfort. Although palateless dentures have been reported to be less rigid than conventional dentures, and require reinforcement to prevent complications, there is little documentation about the effects of such reinforcement. The purpose of this study was to examine the effects of reinforcement on the strain on maxillary implant overdentures supported by implants in a variety of configurations. A maxillary edentulous model with implants inserted in the anterior, premolar, and molar area was fabricated. Five types of experimental overdentures, with and without reinforcement, were fabricated, and two strain gauges were attached at the anterior midline of the labial and palatal sides. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the shear strain on the denture was measured. The measurements were compared using the Kruskal-Wallis test (P = .05). On both the labial and palatal sides, the strain on the palateless dentures with reinforcement was significantly lower than the strain on palateless dentures without reinforcement in all implant configurations (P < .05). The labial strain on the palateless dentures with reinforcement was almost as low as the labial strain on dentures with palatal coverage in most implant configurations. Reinforcement of a palateless implant overdenture with residual ridge reinforcement and a palatal bar could reduce the strain in the anterior midline to almost the same level as a denture with palatal coverage. This type of reinforcement may prevent prosthetic and implant complications.

Can Reinforcement of Maxillary Implant Overdentures Decrease Stress on Underlying Implants?

Reinforcement of maxillary implant overdentures is necessary not only for preventing prosthetic complications but also for protecting underlying structures, as it makes the denture base more rigid. However, few studies have investigated the effects of reinforcement on the underlying structure. The purpose of this study was to examine the effects of reinforcement on implant stress under various implant configurations and denture designs. A maxillary edentulous model with implants and experimental overdentures with and without palatal coverage and three types of cast reinforcement was fabricated. Four strain gauges were attached to the implants in the anterior, premolar, and molar areas. A vertical occlusal load of 98 N was applied through the mandibular complete denture, and the strain on the implants was compared using one-way analysis of variance (P = .05). In dentures with palatal coverage, reinforcement significantly decreased the strain on the anterior and molar implants. In palateless dentures, reinforcement with a palatal bar decreased the strain most on the anterior and molar implants. Reinforcement of maxillary implant overdentures decreased the strain on underlying implants, regardless of the denture design and implant configurations.

Application and Curative Effect of Micro-implant Anchorage in Orthodontics

Purpose: To explore and analyze the curative effects of micro - implant anchorages in orthodontics. Methods: A retrospective analysis of 65 patients undergoing orthodontic treatment in Department of Stomatology, Binzhou Medical University Hospital, Shandong, China was carried out. Thirty four cases in the treatment group were treated with a micro-implant as the anchorage, while 31 cases of the control group were treated with a palatal bar and facebow as the anchorage, and the curative results of the two groups were then compared. Results: After a 13-month treatment, both anchorages were clinically effective, but the micro-implant anchorage showed higher efficacy. Measurement indices for the test group, including sella-nasion - A point (SNA) angle (- 1.88 ± 0.71), sella-nasion-B point (SNB) angle (1.39 ± 0.42), A point - nasion - B point (ANB) angle (- 2.40 ± 0.83), upper central incisor - lower central incisor (U1 - L1) angle (25.79 ± 5.90), upper central incisor - sella - nasion (U1 - SN) angle (- 10.13 ± 3.68), lower central incisor – mandibular plane (L1 - MP) angle (- 4.22 ± 0.45), upper central incisor - nasion - A point (U1 - NA) angle (- 1.32 ± 1.35) and lower central incisor - nasion - B point (L1 - NB) angle (- 1.32 ± 1.35) of the test group were significantly different those of the control group Overbite (OB), overjet (OJ), intercanine width and the width of the first molars of treatment and control groups were also remarkably). Moreover, micro-implant was observed to be more stable during treatment. Conclusion: Compared with traditional anchorages, micro-implants possess the advantages of slighter trauma, simpler operation, more reliable curative effect and high stability. Keywords: Micro-implant anchorage, Orthodontics, Facebow anchorage, Oral medicine, Clinical efficacy

The effect of canine disimpaction performed with temporary anchorage devices (TADs) before comprehensive orthodontic treatment to avoid root resorption of adjacent teeth.

ABSTRACTObjective: The aim of this study was to evaluate the movement of impacted canines away from the roots of neighboring teeth before full-mouth bracket placement, performed by means of TADs to decrease undesired side effects on adjacent teeth. Methods: The study sample consisted of 34 palatally impacted canines, being 19 in the experimental group and 15 in the control group. In the experimental group, before placement of brackets, the impacted canine was erupted by means of miniscrews. In the control group, after initiation of comprehensive orthodontics, canine disimpaction was performed by means of a cantilever spring soldered to a palatal bar. At the end of treatment, volume of lateral incisors and canine root resorption were measured and compared by means of a CBCT-derived tridimensional model. Visual Analogue Scale (VAS) score, bleeding on probing (BOP) and gingival index (GI) were recorded. Clinical success rate was also calculated. Results: The volume of root resorption of lateral teeth in the control group was significantly greater than in the experimental group (p < 0.001). At the end of treatment, VAS score, GI and BOP were not significantly different between the two groups. Conclusion: Based on our results, it seems that disimpaction of canines and moving them to the arch can be done successfully carried out with minimal side effects by means of skeletal anchorage.

Effect of storage time and framework design on the accuracy of maxillary cobalt-chromium cast removable partial dentures.

Statement of Problem:Inaccuracies in the fit of palatal major connectors may be related to distortion of the wax pattern due to prolonged storage time and faulty major connector design.Purpose:This in vitro study was carried out to find out the effect of storage time and major connector design on the accuracy of cobalt-chromium cast removable partial dentures (RPDs).Materials and Methods:A brass metal die with a Kennedy Class III, modification 1, the partially edentulous arch was used as a master die. Thirty-six refractory casts were fabricated from the master die. The refractory casts were divided into three groups (Group I: Anterior-posterior palatal bar, Group II: Palatal strap and Group III: Palatal plate) based on the design of maxillary major connector and subdivided into four groups (sub Group A: 01 h, sub Group B: 03 h, Sub Group C: 06 h, and sub Group D: 24 h) based on the storage time. For each group, 12 frameworks were fabricated. The influence of wax pattern storage time and the accuracy of the fit palatal major connector designs on the master die were compared. Casting defects (nodules/incompleteness) of the frameworks were also evaluated before finishing and polishing. Repeated measures analysis of variance was used to analyze the data.Results:The gap discrepancy was least in sub Group A (01 h) followed by sub Group B (03 h) and C (06 h) and most in sub Group D (24 h). Statistically significant differences (P < 0.05 in all locations L1–L5) in the fit of the framework were related to the design of the major connector. The gap discrepancy was least in Group I (anterior-posterior palatal bar) followed by Group II (palatal strap) and most in Group II (palatal plate).Conclusions:It is recommended that the wax patterns for RPD to be invested immediately on completion of the wax procedure. The selection of a major connector design is crucial for an accurate fit of RPD.

Strain characteristics of Marburg double crown-retained implant overdentures compared with bar and ball-retained implant overdentures, with and without a rigid major connector

It is hard to identify the most favorable retainer type and the denture design when considering strain levels around implants and in edentulous ridges for implant overdentures (IOVD). The purpose of this study was to evaluate the strain transmitted to the implants and edentulous ridges by Marburg double crown (MDC)-retained IOVD as opposed to bar and ball-retained IOVD and the efficiency of a rigid major connector in the maxilla. An in vitro maxillary model was prepared with 4 implants, with strain gauges placed distally to each implant and also in the anterior and posterior edentulous ridges. Five overdentures were fabricated for each MDC and each ball and bar attachment retainers. Vertical loads of 280 N were applied bilaterally on the first molar region. Then the palatal bars of each IOVD were disconnected, and loading procedures were repeated for the prostheses. No significant difference was observed among the MDC and the bar and ball-retained IOVD, with and without a rigid bar according to the data taken from both the implants and edentulous ridges. However, when the strain values attained from each strain gauge separately were considered, a slight difference was observed around the implants of ball-retained overdentures and in the edentulous ridges of MDC-retained overdentures. Within the limitations of this in vitro study, MDC-retained maxillary overdentures with 4 parallel and symmetrically placed implants can be used safely without a rigid major connector as with bar and ball-retained IOVD with regard to the strains generated in the edentulous ridge and around implants.

Procedures adopted by orthodontists for space closure and anchorage control

The aim of this study was to identify the procedures adopted by Brazilian orthodontists in the following situations: extraction space closure, anchorage control in case of necessary anchorage for group A and frequency of skeletal anchorage use, especially in the upper jaw. A questionnaire was sent to the e-mail address of all dentists registered in the Brazilian Federal Council of Dentistry. The results showed that most Brazilian orthodontists usually perform extraction space closure by means of sliding mechanics. The use of palatal bar, inclusion of second molars in the archwire and space closure performed in two phases are the most used techniques for anchorage control in the upper jaw. The skeletal anchorage is referenced by 36.5% of specialists as a routine practice for the upper arch anchorage. There is a wide variety of procedures adopted by Brazilian orthodontists for orthodontic space closure and anchorage control.

Optimization of unilateral molar rotation correction by a trans-palatal bar: a three-dimensional analysis using the finite element method

The main goal of this study was to optimize unilateral molar rotation correction by modifying a trans-palatal arch (TPA) design using the finite element method. Three-dimensional analysis of different TPA designs was carried out using the finite element method. Department of Orthodontics, Tehran University of Medical Sciences, Iran. For this investigation, 13 three-dimensional finite element models were produced for different TPA designs without pre-activation bends. Each model contained a palatal bar and two tubes. Optimizing unilateral molar rotations was achieved by five separate different paths: incorporating U-loop(s), 'R' loop(s) or helix/helices, a reverse action of the helix/helices and adding a straight wire to the design. The mesial part of the left side tube was displaced 0·1, 0·25, 0·5 and 1 mm, successively towards the midline, simulating palatal bar tab engagement in a mesio-palatal rotated maxillary left molar. The mesio-distal force, moment and energy produced in the normal side (right) molar were recorded for each of the models. Findings showed that in all designs, the associated mesializing force was lower than that seen in the traditional design and the moment showed an increasing pattern when compared with a simple palatal bar. Regarding energy levels, the same increasing pattern was observed in the designs between activations of 0·1 and 1·0 mm. According to our optimized system, the TPA design with the highest energy and moment, but the lowest mesializing force associated with derotating a maxillary molar tooth was a parallel wire II design (i.e. adding a straight wire).

A simplified approach to true molar intrusion

BackgroundOrthodontic management of anterior open bites is a demanding task for orthodontists. Molar intrusion as a primary means of open bite correction entails the need for appropriate anchorage. Orthodontic mini implants can provide the required mechanical support. The suggested procedure aims to reduce the risk of complications such as root damage or soft tissue irritations while minimizing overall complexity.MethodsThree female patients aged 14, 18 and 19 years who decided against a surgical correction were treated with a device consisting of mini implants in the palatal slope, a palatal bar and intrusion cantilevers.ResultsIn all three patients, an open bite reduction of more than a millimeter occurred within four months. An anterior overbite of 2 mm or more could be established within 6 to 9 months.ConclusionsThe method presented in this article enables the practitioner to use mini implants in an easily accessible insertion site. A lab-side procedure is optional but not required.

Prevalence of removable partial dentures users treated at the Aracatuba Dental School – UNESP

The aim of this study was to evaluate the frequency of removable partial dentures (RPD) at the Aracatuba Dental School. The study was conducted by analysing 412 clinical history of patients attended at the RPD clinics in the period from 2000 to 2007. 412 charts were analysed: 148 (35.9%) men and 264 (64.1%) women. The mean age was 53.8 years (men) and 52.4 years (women). A total of 556 dentures were made; of these, 233 (41.90%) were maxillary and 323 (58.09%) were mandibular dentures. The most frequent Kennedy classification found was Class III (maxilla) and Class I (mandible). In the maxilla, 55% (126) of the major connectors were of the anterior-posterior palatal bar, while in the mandible, 64% (202) were the lingual bar. As regards the claps, 401 were circumferential and 318 were bar claps. The mean age of the patients was 52.9 years with higher prevalence of female patients; the most frequent Kennedy's classification was Class I in mandible and Class III in maxilla; the most common major connector was anterior-posterior palatal bar for maxilla and lingual bar for mandible; the circumferential clasps were the most common retainer used in both jaws.

Transposition of a maxillary canine and a lateral incisor and use of cone-beam computed tomography for treatment planning

This report describes the orthodontic treatment of a 12-year-old girl with transposition of the maxillary left canine and the lateral incisor. Cone-beam computed tomography was used during treatment planning. The transposed tooth positions were corrected with an unconventional orthodontic approach. Treatment alternatives and their clinical concerns are presented.

30-year life span of a spring cantilever bridge: case report

Besides other indications, the spring cantilever bridge can solve the difficult clinical problem of providing diastema on either side of a pontic. Unlike the conventional bridges, it has a somewhat controversial design in that the anterior pontic is connected to its retainer on a posterior abutment by a relatively long flexible palatal bar. This paper presents a case report of a spring bridge which fractured due to metal fatigue after 30 years of continued service. Other studies reported a mean life span of 8-10 years for conventional bridges. The advantages of the spring cantilever bridge are also discussed.