The Orthodontics Professors
the latest in contemporary & evidence-based orthodontics
BY MATTHEW LARSON & TATE H. JACKSON
80 patients being treated at the Texas A&M School of Dentistry enrolled in this randomized trial to test whether daily or weekly text message reminders might better improve oral hygiene. At the start of the study, all patients had been in upper and lower fixed appliances for at least 4 weeks, spoke English, were between the ages of 12 and 17 years, and were more than 6 months from the end of active treatment.
Patients (not their parents) received texts through a third-party company that provides such services. In that way, the randomized groups could be blinded from the study authors. Patients received one of three types of text messages: 1) oral hygiene texts (e.g. “Don’t forget to brush your teeth twice a day!’’), 2) shorter treatment time texts (e.g. “Your time in braces will be shorter if you keep your mouth very clean!”), and 3) motivational texts (e.g. “Research shows that a better smile leads to better-paying jobs”).
After 8 weeks of text messages, bleeding, plaque, and gingival indices were all measured by a single blinded examiner. All indices were all significantly lower for the daily text group compared to the weekly text. The largest difference between groups was found in the bleeding index, where number of sites with bleeding on probing decreased 48% in the daily group but only 27% in the weekly group.
When surveyed, 97% of patients thought that text messages were helpful, and 70% preferred texts in the evening (7-9PM was the most preferred time). In regards to patient preference on texting frequency, 57% reported they preferred text reminders daily or twice a day, while an additional 20% preferred 3-4 times a week. Texts related to a reduction in treatment time were reported by patients to be most motivational.
WHAT THE PROFESSORS THINK
This study was well-designed. The use of a third-party company to deliver the text messages was helpful in two ways. First, it allowed for better blinding; the clinicians treating the patients were not responsible for sending the reminder messages. Second, the use of currently-available technology through this service makes the results more likely to be clinically relevant.
Although overall well-designed, there are also a few limitations to be discussed. First, it is always difficult observing oral hygiene in studies due to the Hawthorne Effect – oral hygiene will typically improve to some degree simply because patients are enrolled in a study. Also, the daily messaging group had slightly lower periodontal indices at baseline, although only the plaque index was statistically significant. These limitations likely do not change the validity of the results, but a slightly lower overall improvement may be seen in private practice.
Although the use of daily text messages only marginally increased patient oral health, the study was constructed in such a way as to provide helpful data to practicing orthodontists. Nearly all orthodontists already stress the importance of daily compliance with hygiene, elastics, and diet – this study supports those statements and leverages current technology to help support patients in those areas. By using multiple messages and by surveying patients regarding message preference, the results of this randomized trial were made more informative.
Importantly, the patients themselves received the text message reminders, and the patients reported their preferences, not their parents. In an age when the majority of teenagers have a cell phone, this aspect of the study design is critical.
So, for an orthodontist trying to motivate a teenager in braces, what do these data tells us?
Article Reviewed: Mike C. Ross; Phillip M. Campbell; Larry P. Tadlock; Reginald W. Taylor; Peter H. Buschang. Effect of automated messaging on oral hygiene in adolescent orthodontic patients: A randomized controlled trial. Angle Orthodontist. Online 2018.
A Tribute to Prof – Sarver, Fields, Larson, Vig, Turpin, McNamara, Johnston, & The Professors Remember Him in Their Own Words
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BY TATE H JACKSON AND TUNG T NGUYEN
A group at the University of California at Los Angeles (UCLA) have conducted a retrospective study to evaluate how rapid palatal expansion with mini-implants placed in the palate works in post-pubertal patients.
15 participants (9 female) with ages ranging from 13.9 to 26.2 years were all consecutively-treated with a modified Wilmes-style hybrid tooth-borne / mini-implant borne maxillary expansion appliance. 14 of these patients were in dental crossbite. The need for expansion was determined by measuring and comparing maxillary and mandibular casts, not by comparison to population norms.
All participants were treated with the hybrid tooth/mini-implant expander alone; no other appliances were in place during expansion. The authors report that all mini-implants were placed in the posterior palate with bicortical anchorage.
The hybrid expander was turned twice each day (0.25mm per turn) until “a diastema appeared” and then just once per day. The expansion devices were maintained for 3 months following the end of activation.
Cone-beam CT (CBCT) images were obtained for each participant before treatment and within 3 weeks of the end of active expansion, but before any additional active appliances were placed.
After cranial base superimposition of the pre- and post-expansion volumes, transverse expansion was measured in coronal sections at the level of the Upper Zygoma (frontozygomatic suture), Lower Zygoma (zygomaticomaxillary suture), and Maxillary Molars.
Expansion resulted in little transverse change at the Upper Zygoma [mean of 0.52mm (SD 0.37mm]. An average of 4.62mm (SD 1.33mm) of expansion occurred at the Lower Zygoma, and 8.33mm (SD 2.29mm) occurred at the Molar.
Taken together, for every 1mm of transverse expansion, the zygomaticomaxillary complex rotated outward by 0.6 degrees on each side.
Stated another way, an average of 6.8mm in expansion at the level of the jackscrew resulted in an average of 8.33mm of expansion at the molars, with an average of 2 degrees of total outward tipping of the molars on each side. It is important to note that tipping of the molars was highly variable, with standard deviations reported that were nearly double the mean.
WHAT THE PROFESSORS THINK
The consecutive case series reported in this paper represents a well-constructed study, despite the limitations of retrospective data analysis. Superimposition of CBCT volumes and analyses of transverse changes were founded on validated methods, and reliability of the measurement made were adequately measured and reported.
It is unfortunate that the authors did not report the rate of adverse outcomes for the participants in the study. e.g. Did any of the mini-implants fail?
The paper focused a bit more on theoretical biomechanical outcomes, such as where the center of rotation might be for the skeletal units involved, than is likely to be helpful for practicing orthodontists.
Some practical points can be gleaned, however:
1. When using a hybrid bone/tooth borne maxillary expander in later-adolescent to early adult patients, you should expect some “tipping” of the molars. That tipping happens due to a combination of skeletal rotation, and to a lesser degree, change in inclination of the molars.
2. Based on this study alone, the amount of molar tipping that occurs can be quite variable. As little as 4 degrees of total tipping might occur, or as much as 10 degrees. From previously published studies, the amount of tipping using mini-implants should certainly be expected to be less than with tooth-borne expansion alone, however. (1, 2)
3. In order to give a patient good estimates of the likelihood of both success and adverse outcomes with this treatment, more data are needed.
These data represent good initial guide-points for orthodontists in practice and suggest that mini-implant maxillary expansion should be considered in younger non-growing patients with skeletal transverse issues.
The prudent orthodontist, however, will communicate with the patient / parents that although the procedure is a great alternative to more invasive surgery, it still carries with it some real risk and uncertainty at this time.
Article Reviewed: Cantarell D, et al. Midfacial changes in the coronal plane induced by microimplant-supported skeletal expander, studied with cone-beam computed tomography images. Am J Orthod Dentofac Orthop 2018; 154:337-345 (Sept).
1) Lin L, Ahn HW, Kim SJ, Moon SC, Kim SH, Nelson G. Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence. Angle Orthod. 2015;85:253–262
2) Mosleh MI, Kaddah MA, Abd ElSayed FA, ElSayed HS. Comparison of transverse changes during maxillary expansion with 4-point bone-borne and tooth-borne maxillary expanders. Am J Orthod Dentofacial Orthop. 2015;148:599–607.
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By WILLIAM R. PROFFIT, DDS, PhD
At the Case-Western Reserve Dept. of Orthodontics, cone-beam CT images were used to evaluate the shape and location of the mandibular buccal shelf below the molars in white (European descent) patients as possible sites for skeletal anchorage. The cortical bone at this location has been used by orthodontists working with Asian patients, and excellent success (93%) with bone screws there has been presented.(1)
The objectives in this study were to:
Cone-beam CT images for 30 adolescent white patients who had CBCT’s as part of their diagnostic evaluation were used to obtain a detailed view of the mandible in the first and second molar region (Figures 1 and 2). Cortical shelf thickness and the width of the buccal shelf bone were measured at the distal of the first molar and at the mesial and distal of the second molar. Then, the position of the mandibular nerve at these locations was established and its distance from a visual screw placed vertically was measured.
The data showed that cortical bone thickness was greatest below the disto-buccal cusp of the second molar (8.1 + 1.3 mm), and that although this also was the point of greatest proximity to the mandibular neurovascular bundle (5.5 + 1.6 mm), this amount of clearance would provide adequate safety. Based on these measures, the authors recommended a 10 mm anchorage screw with a 5 mm screw head extension in this location. Locations below the first molar, not the second molar, have been recommended for Asian patients. Whether this recommendation is related to a clinically significant difference in mandibular anatomy between the two racial groups is not known.
WHAT THE PROFESSOR THINKS
Alveolar bone screws have proved to be acceptable as anchorage for minor tooth movement but disappointing as anchorage for major tooth movement. For example, two clinical trials of a Nance lingual arch vs. alveolar bone screws for maxillary incisor retraction found no advantage with the bone screws—the two anchorage types were equally ineffective.
It has become clear that cortical bone of the palate does offer almost perfect anchorage for intrusion, retraction and protraction of maxillary dental segments or the whole maxillary dental arch(2), and palatal anchorage now is preferred.
Is the cortical bone of the buccal shelf of the mandible equally superior to mandibular alveolar bone? The existing data from Asian patients certainly indicates that for them, it is. This report for white adolescents shows that:
Based on these points, it is reasonable to expect bone anchors in the buccal shelf to be more stable than bone screws in the mandibular alveolus. However, there are no studies yet with high-quality outcome data for white patients to be certain that this is correct.
Should American clinicians now start using bone screws into the mandibular buccal shelf for white as well as Asian patients when movement of mandibular segments or the whole mandibular arch is needed?
On balance, I would say yes.
Article Reviewed: Elshebiny T, Palomo JM, Baumgartel S. Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients. Am J Orthod Dentofac Orthop 2018; 153:505-511 (Apr).
Tate H. Jackson, DDS, MS