Orthodontics : the art and practice of dentofacial enhancement最新文献

Aim: To evaluate and compare in vitro the shear bond strength of rebonded orthodontic brackets among the three most frequently used rebonding methods--sandblasting, direct flaming, and grinding with a green stone bur. The surface characteristics of new and rebonded bracket bases were also compared using scanning electron microscopy (SEM).

Methods: The sample used in the present study comprised 60 extracted human premolars bonded with brackets. The sample was divided into three groups (each n = 20; sandblasting, direct flaming, and grinding with a green stone bur). SEM was used to compare the surface characteristics of the new and rebonded bracket bases for all three groups.

Results: The Z test for the direct flaming and grinding groups revealed statistically significant bond strength (P < .05). The ANOVA test for all three groups showed P < .05, which is statistically significant. SEM for the sandblasting method showed well-defined retentive areas.

Conclusion: When rebonding brackets, sandblasting the bracket base yields the highest bond strength.

Objective: To compare the anchorage potential of mini-implants with modified Nance palatal buttons during simultaneous first and second maxillary molar distalization.

Methods: Mini-implants (1.4 x 10 mm) placed to obtain indirect anchorage for maxillary molar distalization using a superelastic Ni-Ti open coil spring were compared with anchorage derived from a modified Nance palatal button incorporated in a distal jet appliance. Appliances were placed bilaterally in 19 adolescent patients. Lateral cephalograms with guide wires to differentiate the right from left sides were used for evaluation. All measurements (angular and linear) were obtained from these guide wires.

Results: Anchorage loss at the first premolar was 13% with mini-implant-supported Ni-Ti coil spring appliances and 24.75% with the Nance palatal button (distal jet appliance) on the right side. On the left side, anchorage loss was 15.4% with mini-implant-supported Ni-Ti coil spring appliances and 23.9% with the Nance palatal button (distal jet appliance).

Conclusion: Mini-implants do not provide absolute anchorage when used indirectly. However, anchorage conservation is more efficient than modified Nance palatal buttons.

Vertical maxillary asymmetry (VMA) is a condition characterized by distinct morphologic features: dentoalveolar asymmetry, canted nasal floor and occlusal plane, and asymmetric lip elevation. An extensive literature search failed to produce depictions of differential vertical asymmetry in conditions other than specific congenital or pathologic symptoms, the most prominent of which are presented in this report for comparison with VMA. The records of nine patients illustrate the localized nasal/maxillary/occlusal vertical asymmetry, which does not affect the orbits or the mandible. Although a prevalent rotational roll in spatial orientation is observed with VMA, many patients exhibit deviations in the other rotational planes of space (pitch and yaw). Potential etiology includes dentoalveolar compensation to localized skeletal or dental disturbances and possibly neuromuscular origins. Treatment approaches, prevention, and research avenues are discussed. Regardless of future confirmation of VMA as an independent entity encompassing hard and soft tissue components, its establishment as a phenotype associated with malocclusion warrants its inclusion in orthodontic diagnosis, with a possible impact on treatment planning and conduct. Moreover, its introduction as a diagnostic feature of malocclusion justifies the incorporation of the posteroanterior cephalograph as a key pretreatment record in orthodontics.

Sliding mechanics have become a popular method for space closure, with the development of preadjusted edgewise appliances. Furthermore, various space closing auxiliaries have been developed and extensively evaluated for their clinical efficiency. Their effectiveness is enhanced with optimum force magnitude and low load deflection rate/force decay. With the advent of nickel-titanium (Ni-Ti) springs in orthodontics, load deflection rates have been markedly reduced. To use Ni-Ti springs, clinicians have to depend upon prefabricated closed coil springs. The open coil traction system, or open coil retraction spring, is developed utilizing Ni-Ti open coil springs for orthodontic space closure. This article describes the fabrication and clinical application of the open coil traction system, which has a number of advantages. It sustains a low load deflection rate with optimum force magnitude, and its design is adjustable for a desired length and force level. It is fail-safe for both activation and deactivation (ie, it cannot be overactivated, and the decompression limit of the open coil is controlled by the operator). The open coil traction system can be offset from the mucosa to help reduce soft tissue impingement.

Aim: To evaluate the soft tissue changes in upper lip, vermilion, and alar bases after surgically assisted rapid palatal expansion (SARPE). A new flap design was proposed to obtain more esthetic results.

Methods: Sixteen patients who had undergone SARPE for skeletal deformities were evaluated. None of the patients treated had any previous maxillary or nasal surgery, nor did they have any previous trauma to the midface. The soft tissue was clinically evaluated before and after surgery. Lip length and width were traced and measured on the radiograph, both preoperatively and postoperatively, by the same investigator. Preoperative and 6-month postoperative photographs were added.

Results: The data suggested that the greater the stability in the soft tissue, particularly in the vermilion width and alar base, the more conservative the maxillary vestibular incision could be.

Conclusion: A conservative anterior vestibular incision at 6 months resulted in better esthetics, influencing a smaller loss of vermilion and less widening of alar bases. Otherwise, a traditional incision associated with decreased lip length slightly increased with the modified incision. SARPE can be effectively performed with a more conservative vestibular incision to prevent excessive scarring and shortening of the lip to achieve predictable results.

The proper placement of mini-implants is very important because of the increased risk of implant failure when inserted too close to the roots of the adjacent teeth. This can interfere with orthodontic treatment. This simple guide for mini-implant placement is easy and can reduce chair time.

Aim: To cephalometrically compare the overjet, overbite, and molar and canine relationship stability of Class II malocclusion treatment with and without maxillary premolar extractions.

Method: Two groups of 30 patients each with pre- and posttreatment matching characteristics and satisfactory finishing were used. Group 1 consisted of 30 patients treated with nonextraction at a mean pretreatment age of 12.14 years, while group 2 consisted of 30 patients treated with maxillary first premolar extractions at a mean pretreatment age of 12.87 years. Lateral cephalograms obtained before and after treatment and at a mean of 8.2 years after the end of treatment were compared. Student t tests were used to compare the initial and final dental relationships of the groups and the amount of treatment and long-term posttreatment changes. Pearson correlation coefficients were calculated to investigate correlations between treatment and long-term posttreatment dental relationship changes.

Results: In groups with matching canine relationship treatment changes, long-term stability of the overjet, overbite, and molar and canine relationships were similar in the groups. There were significant but weak correlations between treatment changes in overjet, overbite, and canine relationships with their long-term posttreatment changes.

Conclusion: Nonextraction and maxillary premolar extraction treatment of complete Class II malocclusion have similar long-term posttreatment stability in terms of overjet, overbite, and canine and molar relationships.

Aim: Various alternatives to metal orthodontic archwires have produced varied successes over the years. This study sought to evaluate the bending properties of fiber-reinforced polymeric composite (FRC) archwires compared with similarly sized nickel-titanium (Ni-Ti) archwires.

Methods: Two different 0.018-inch translucent FRC orthodontic wires (Translucent Archwire I and Translucent Archwire II) were tested against 0.014-, 0.016-, and 0.018-inch nonsuperelastic nickel titanium orthodontic wires. The wires in each group (n = 10) were evaluated with three-point bending using a universal testing machine. Wire segments were deflected at midspan to 3.1 mm at a rate of 2 mm/min. Loading and unloading slope and modulus were calculated, as were force values during activation and deactivation and elastic recovery.

Results: It was found that the 0.018-inch Ni-Ti archwire demonstrated the highest force values at different deflection distances followed by Translucent Archwire II, 0.016-inch Ni-Ti, Translucent Archwire I, and finally 0.014-inch Ni-Ti. 0.016-inch Ni-Ti exhibited the highest modulus value, followed by 0.018-inch Ni-Ti, 0.014-inch Ni-Ti, Translucent Archwire II, and finally Translucent Archwire I. During deactivation, the elastic recovery of 0.014-inch Ni-Ti and 0.016-inch Ni-Ti was significantly greater than Translucent Archwire II.

Conclusion: The bending properties of BioMer's FRC archwires were found to be comparable to Ni-Ti, as advertised by the manufacturer.

Management of missing lateral incisors requires thorough treatment planning and an interdisciplinary approach. Occlusion and alignment are significant considerations. Three treatment options are available for replacing missing lateral incisors: canine substitution, tooth-supported restorations, and single-tooth implants. The ideal treatment is the one that satisfies the esthetic and functional requirements of the patient. The pros and cons of the various treatment options must be meticulously analyzed before arriving at a decision. This article closely examines patient selection and illustrates the importance of interdisciplinary treatment planning in an adult treated with canine substitution and orthognathic surgery.

Aim: The experience of pain is considered a major issue during active orthodontic treatment with fixed appliances. The objective of this study was to indirectly and retrospectively evaluate patients' perceptions of orthodontists' awareness to their pain during active orthodontic treatment.

Methods: A structured questionnaire was distributed to 100 patients undergoing active orthodontic treatment with fixed appliances. The patients were treated by at least 35 orthodontists. The questionnaire accessed information regarding instructions the patients received from their orthodontist concerning pain management during and following treatment.

Results: Most of the patients (83%) reported that their orthodontist informed them about expected pain during orthodontic treatment. Fifty-nine percent informed their orthodontist of pain during treatment (64% girls and 33% boys). Only 21% of the patients were recommended to take analgesic to relieve the pain and only 7% patients received a prescription for an analgesic to relieve their pain.

Conclusion: Orthodontists should consider prescribing analgesics more frequently.