Orthodontics 4/2011

Guest Editorial: The importance of knowledge and the benefits of interdisciplinary treatment

Nah�s-Scocate, Ana Carla Raphaelli
Page 285 - 286

Treatment planning challenge 4: Dental and facial asymmetry�whether and on what to operate

Page 288 - 289

In vitro evaluation of fluoride release of orthodontic bonding adhesives

Pithon, Matheus Melo / Santos, Rogerio Lacerda dos / Ruellas, Ant�nio Carlos de Oliveira / Nojima, Lincoln Issamu / Sant�anna, Eduardo Franzotti
Page 290 - 295
Aim: To assess the fluoride release from adhesives used for bonding in orthodontics.
Methods: Six bonding agents were evaluated: five adhesives (Biofix, Fill Magic Orthodontic, EagleBond, Orthobond, and Transbond XT) and one resin-reinforced glass-ionomer cement (Fuji Ortho LC), the latter serving as a control. Ten samples of each adhesive were stored in containers with 5 mL of deionized distilled water at 37�C. Fluoride release was measured with an ion-specific electrode. Readings were taken periodically for a total of 33 days. On day 28, all samples were immersed in a 0.221% sodium fluoride solution for 5 minutes to assess their recharge potential. Descriptive statistics were calculated for the fluoride release rates of each material. ANOVA with multiple comparisons and the Kruskal-Wallis tests (P < .05) were used to assess differences between the groups.
Results: All adhesives released significant amounts of fluoride (P < .05). During the first day, Biofix released the highest amount of fluoride, followed by Fuji Ortho LC, which also showed the highest fluoride release from day 7 to day 33. The fluoride release from Biofix and Fuji Ortho LC decreased by the third day to 40% of its original value. All other adhesives maintained their fluoride release with only small fluctuations.
Conclusion: All the materials released significant amounts of fluoride, with Biofix having the highest release in the first 3 days and Fuji Ortho LC over the total length of the experiment.

Agenesis of maxillary lateral incisors: A global overview of the clinical problem

Kavadia, Smaragda / Papadiochou, Sofia / Papadiochos, Ioannis / Zafiriadis, Lazaros
Page 296 - 317
The agenesis of maxillary lateral incisors is a common developmental anomaly and represents a clinical problem impairing dental esthetics and function from a very young age. Several dental specialties deal with the management of this clinical problem because a multidisciplinary approach can cover the complete dental needs of patients with dental agenesis. There is controversy, however, about whether missing lateral incisor spaces should be orthodontically opened or closed using permanent canines to replace the missing teeth. The article presents a review of the existing literature about the prevalence, etiology, diagnostic evaluation, and treatment strategy of maxillary lateral incisor agenesis. Also, this article aims to present the key determinants leading to selection of space opening or closure and to report professional judgments and layperson perception concerning the available treatment alternatives. The English-language literature associated with this topic was searched via PubMed. The articles retrieved were then reviewed with an attempt to fulfill the aims of this review. Maxillary lateral incisors are one of the most common congenitally missing teeth, and to date, the origin of their agenesis has not been completely identified. Prompt diagnosis and careful evaluation of treatment determinants through a multidisciplinary approach are essential for the proper management of clinical problems. Each of the available means of rehabilitation has its own advantages, disadvantages, indications, and limitations. The configuration of the treatment plan should be devoid of clinician biases, whereas patients' realistic expectations should be taken into account.

Evaluation of the power arm in bringing about bodily movement using finite element analysis

Ansari, Tariq Ajaz / Mascarenhas, Rohan / Husain, Akhter / Salim, Mohammed
Page 318 - 329
Aim: To evaluate the effectiveness of the power arm in bringing about bodily movement and to determine the ideal length and location of the power arm.
Methods: A geometric model of the maxillary right canine was constructed and subsequently converted to a finite element model. Material property data were represented, boundary conditions were defined, and force was applied. Different situations were simulated in which a power arm of varying vertical lengths were attached at different locations on the tooth�namely, the incisal, middle, and cervical thirds.
Results: The amount of bodily movement is maximum when the force is delivered directly at the cervical third. It decreases at the middle third and is least when attached at incisal third. The varying lengths of the power arm for a particular site of attachment does not bring about any change in the movement.
Conclusion: The attachment of the power arm at the cervical third brought about maximum bodily movement, followed by the middle and incisal thirds. Variations in length of the power arm at different sites of attachment did not bring any change in the outcome. Thus, the point of attachment is critical in bringing about bodily movement.

Does the design of self-ligating brackets show different behavior in terms of friction?

Tecco, Simona / Marzo, Giuseppe / Di Bisceglie, Beatrice / Crincoli, Vito / Tet�, Stefano / Festa, Felice
Page 330 - 339
Aim: This in vitro study evaluated the friction generated by aligned stainless steel conventional brackets, self-ligating Damon MX brackets, Time3 brackets, Vision LP brackets, and low-friction Slide ligatures coupled with various stainless steel, nickel-titanium (Ni-Ti), and beta-titanium (TMA) archwires.
Methods: All brackets had a 0.022-inch slot; the orthodontic archwires were 0.014-inch Ni-Ti, 0.016-inch Ni-Ti, 0.014 � 0.025-inch Ni-Ti, 0.018 � 0.025-inch Ni-Ti, 0.017 � 0.025-inch TMA, 0.019 � 0.025-inch stainless steel, and 0.019 � 0.025-inch Ni-Ti. Each bracket-archwire combination was tested 10 times.
Results: Coupled with 0.014-inch Ni-Ti and 0.016-inch Ni-Ti archwire, conventional brackets generated the greatest friction, while Damon MX and Vision LP brackets generated the lowest (P < .05). No significant difference was observed between Time3 brackets and Slide ligatures. Coupled with all the rectangular archwires, Victory Series brackets, Slide ligatures, and Vision LP self-ligating brackets generated significantly lower friction than Time3 and Damon MX self-ligating brackets (P < .05).
Conclusion: These findings suggest that self-ligating brackets are a great family of brackets that, in vitro, can generate different levels of friction when coupled with thin, thick, rectangular, or round archwires. Clinical conclusions based on our results are not possible, due to the limitations of the experimental conditions.

Speech defect and orthodontics: A contemporary review

Doshi, Umal Hiralal / Bhad-Patil, Wasundhara A.
Page 340 - 353
In conjunction with the lips, tongue, and oropharynx, the teeth play an important role in the articulation of consonants via airflow obstruction and modification. Therefore, along with these articulators, any orthodontic therapy that changes their position may play a role in speech disorders. This paper examines the relevant studies and discusses the difficulties of scientific investigation in this area. The ability of patients to adapt their speech to compensate for most handicapping occlusion and facial deformities is recognized, but the mechanism for this adaptation remains incompletely understood. The overall conclusion is that while certain malocclusions show a relationship with speech defects, this does not appear to correlate with the severity of the condition. There is no direct cause-and-effect relationship. Similarly, no guarantees of improvement can be given to patients undergoing orthodontic or orthognathic correction of malocclusion.

Comparison of two imaging programs in predicting the soft tissue changes with mandibular advancement surgery

Ravindranath, Sneha / Krishnaswamy, Nathamuni Rengarajan / Sundaram, Venkateswaran
Page 354 - 365
Establishing common objectives and expectations concerning the outcome of proposed surgical orthodontic therapy is a crucial part of the treatment planning process, which has been greatly simplified by imaging software. The purpose of this study was to investigate the reliability of two surgical imaging programs�Dolphin Imaging 10 and Vistadent OC�in simulating the actual outcome of mandibular advancement surgery by using a visual analog scale (VAS) judged by a panel of orthodontists, oral surgeons, and laypersons. The predictions were also analyzed with soft tissue cephalometric evaluation. The results of the study showed that in predicting the surgical outcome evaluated by the VAS, both programs received a mean rating of fair. One was marginally superior for the overall assessment among all three panelist groups. Region-wise, rating indicated the lower lip region to be the least accurate, and the submental region received the highest scores. The soft tissue cephalometric parameters showed minimal differences except for the lower lip parameters. Thus, Dolphin Imaging 10 and Vistadent OC are reliable in predicting mandibular advancement surgical outcomes with inaccuracies chiefly in the lower lip region.

Anterior dental alignment and smile: Perception and sensations in a sample of 8- to 10-year-old children and their parents

Lombardo, Luca / Berveglieri, Chiara / Guarneri, Maria Paola / Siciliani, Giuseppe
Page 366 - 377
Aim: To describe the perception and sensations that dental alignment and smile determine in a sample of 180 children aged between 8 and 10 years, to assess whether there is a general trend in the classification of smiles, and to understand the influence of background attractiveness and sexual traits on the judgment of smile in the sample of children and 150 parents.
Methods: We employed visual media showing a smile in four different arrangements (ideal incisal occlusion [N], median diastema [D], incisal crowding [A], and protruding incisors [P]), in both a dynamic and static way, with and without background attractiveness.
Results: Trends were found among responses to the four classes of videos and photographs: The boy's smile gained a higher score than the girl's smile. In both the boy and girl presentations, there was an important preference to the following sequence of smiles: N, D, A, and P. Furthermore, the girl photographs showed no relevant difference between A and D.
Conclusion: This study showed that there are no different perceptions and sensations due to the variation of dental alignment. There is a general trend in the classification of smiles according to dental alignment. Background attractiveness and sexual traits influenced the judgment of smile.

Double impact: Intrusion of two mandibular molars using an SAS�A case report

Dholakia, Kartik D. / Bhat, Shweta R.
Page 378 - 385
The size of the envelope of tooth movements using fixed mechanotherapy has been increased with the use of temporary anchorage devices (TADs). Orthodontic mini-implants, a form of TADs, have been successfully used for achieving a variety of tooth movements, such as bodily retraction, extrusion, protraction, and even intrusion of maxillary molars. However, the use of orthodontic mini-implants for intruding mandibular molars is questionable due to anatomical constraints. Skeletal anchorage systems (SASs), another form of TADs, overcome these limitations to give promising results for mandibular molar intrusion. The following case report shows the use of unilateral SAS for intruding two mandibular molars and extruding a maxillary molar of the same side to establish a stable occlusal plane. The amount of intrusion achieved in relation to mandibular molars was evaluated by comparing panoramic images. The mandibular left first and second molars were intruded by approximately 1.6 and 2.5 mm, respectively, in relation to the occlusal plane.

A segmented appliance for space closure followed by Invisalign and fixed appliances

Uribe, Flavio / Cutrera, Alice / Nanda, Ravinda
Page 386 - 395
This case report describes the use of a segmented appliance for space closure prior to using Invisalign. The maxillary right canine was retracted into the extracted first premolar space with a sectional wire from the first molar to the canine with no visible brackets in the incisor region. The advantage of this technique is the ability to achieve better root and rotational control during space closure with a fixed appliance that also has limited visibility. A maxillary fixed appliance was used to refine the esthetics in the maxillary arch due to the limitations of the Invisalign appliance in achieving rotational and vertical movements.

Mini-implant�supported sliding jig

Pattabiraman, Vinod / Kumari, Shashikala / Sood, Raghav
Page 396 - 399
Maximum anchorage situations require appropriate anchorage control from the very beginning. This includes control of anchorage in the anteroposterior as well as vertical directions. The requirement is more critical in patients with vertical growth patterns. Loss of anchorage in such situations requires recovery mechanics that will not tax the anchor teeth in any direction while maximizing efficiency. This article describes the use of a mini-implant�supported sliding jig in one such case where unilateral anchor loss in the maxillary arch was observed. A modified sliding jig was supported with Class II elastics stretched from a mini-implant placed in the mandible. With little patient compliance, the mini-implant was used to distalize the maxillary molar to regain the lost space and achieve ideal results in the most efficient way.

Crimpable double tubes for segmental retraction

Martins, Renato Parsekian / Gandini, Luiz Gonzaga Jr / Martins, Isabela Parsekian / Martins, L�dia Parsekian
Page 400 - 403
When a T-loop is used in segmental mechanics, it is generally attached posteriorly to an auxiliary tube in the first molars and anteriorly to a crimpable cross tube or a Burstone canine bracket. This article illustrates the use of a crimpable tube with a 90-degree bend on the base wire to secure a T-loop in segmental retraction. Both of these approaches allow a T-loop to be reactivated in a simple manner without undesirable changes in the system of forces, which could happen if the T-loop is skewed posteriorly.

Treatment planning challenge 4: Outcome

Page 404 - 405

Mastery: Generating power and high performance

Cooper, Marc
Page 406 - 408

Vignettes: A crooked path to straightening teeth

Baumgaertel, Sebastian
Page 409 - 409

Letter to subscribers

Romano, Rafi
Page 284 - 284