v. 16, no. 5
Dental Press Journal of Orthodontics – ISSN 2176-9451
Dental Press J. Orthod.
v. 16, no. 5
September / October
Articles, websites or books. Where to find the information we need?
Where should we seek information if we need to make a treatment decision? In an article, website or book? Curiously, this is not as straight forward as it may seem for most professionals, and be even more confusing for laypersons. Let us roll up our sleeves and address the issue.
Scientific articles are the most precious source of information available today. They provide the most current, up-to-date information and if we take a close look at a study design we can easily understand the place occupied by that particular study in the pyramid of evidence. In other words, equipped with some knowledge of evidence-based dentistry a reader can assess exactly to what extent a given article is relevant to clinical practice. Furthermore, articles have to prove their mettle by meeting stringent requirements before publication in a journal. Thus, information is filtered and polished prior to being delivered to the reader. A shortcoming of scientific articles lies in the fact that they target professionals, not laypersons. Websites offer the advantage of making information accessible to laypersons.
However, websites are probably the most controversial sources of knowledge. They are a mixed bag, ranging from great to lousy. They gave rise to the most famous and widely consulted doctor today: Dr. Google. This doctor arouses radically contradictory feelings. At times we are truly happy to see Dr. Google help someone to avert an inadequate treatment. On other occasions, it provides patients with dreadful content, and we are hard put to spend a huge amount of time and saliva to explain why it is wrong. We can never warn enough that Dr. Google is not a fully reliable source of information, and professionals are advised to resort to it with caution.
The problem of information on the Internet is that websites will accept any and all information. As a result, a whole lot of ignorance is being spread on the Internet. However, there are also fantastic initiatives committed to clarification and knowledge, such as the Cochrane Collaboration,1 a space where readers can find the most authoritative content on various health care themes. The Cochrane Collaboration has been cited as an enterprise that rivals the Human Genome Project in its potential implications for modern health treatments. This is a source for laypersons and professionals alike.
It is curious that although books have been our companions for centuries, they are still largely misunderstood by people in general. An old adage says that in order for a person to feel fully accomplished they need to plant a tree, write a book and beget offspring. Nevertheless, it takes a little browsing in a bookstore to see hundreds, perhaps thousands, of low quality books. How do we sort the wheat from the chaff in health care? It?s elementary. We must understand the role books play in our particular area.
Books will passively accept information of any quality on their pages. In fact, good books comprise an author?s approach to a given subject or subjects, usually based on topics they had previously addressed in scientific articles. That is, the author has published several articles. This information was tested by the scientific community and from a certain moment onward the author will consistently organize such body of information and put it into context for the readers. Often, outsiders? eyes will fail to see in these articles the alignment and consistency that is so obvious to the author, and which they expound in their book. Thus, this type of source provides a unique overview of the work carried out by someone or a group.
It is precisely due to their readability and consistency that books are often used by undergraduate students. The goal is to render information that is more user-friendly and intuitive, and thus ideal when taking the first steps in professional training.
One great example is the book Controversies in Orthodontics and Atlas of Tooth Movement Biology, by Alberto Consolaro.2 In his book the author rounds up the information initially presented in the form of articles, which were sieved by the dental community, thereby providing an overview of the author?s amazing stances on a wide range of issues tackled in day-to-day clinical practice.
Thus, there are all sorts of scientific articles, websites and books. Make sure to choose your source wisely.
What´s new in Dentistry
Expanding therapeutic boundaries: Stem cells and tissue engineering
Over the last decade, research in dentistry has been evolving expressively in the field of tissue engineering. The search for means to achieve tissue repair, or the generation of new tissue, has the goal to broaden dramatically the therapeutic possibilities over different areas. Tissue engineering is a very promising option for providing tissue for craniofacial repair.5 When added up, the incidence of incisor pre-foramen fissures, which involve the alveolar ridge, and of incisor transforamen fissures, the presence of a full or partial alveolar cleft affects something like 70% of the cleft lip and palate patients.
From an orthodontic therapy point of view, the presence of an alveolar cleft represents the greater management challenge for limiting dental movement in the area adjacent to the cleft. It is paramount to be aware to the constraints imposed by this condition to patients rehabilitation.1,2,11,12 Aimed at facing this difficulty, the use of secondary alveolar bone graft has been considered the first choice of treatment. Although its efficacy has been largely registered by both literature and clinical practice, this procedure involves complex issues such as cost, general anesthesia, the need for an orthopedic practitioner when the donor site is the iliac crest, morbidity, amongst others. New discoveries have been pointing out towards the development of less invasive and equally efficacious strategies. The American Association of Orthopaedic Surgeons suggests that, given the high demand for grafting procedures, the development and supply of ?substitutes for conventional bone grafts? should be a priority. In a recent study,5 embryonic stem cells have been differentiated into cartilage cells and implanted on artificially created cranial osseous defects. In comparison to the control group, the group that received the implanted tissue had a significantly faster response rate. [...]
Intrusive mechanics generates inclination forces and orthopedic stimulus followed by simultaneous dental repositioning and bone remodelling or Intrusion forces are not applied in intrusive mechanics, but intrusive effects are still obtained
Intrusion. Orthodontics. Orthopedics. Periosteum.
Interview with Stephen Yen
? B.A. in Biology from Harvard College.
? D.M.D. from Harvard School of Dental Medicine.
? Orthodontic Specialty Training from University of Southern California.
? PhD in Craniofacial Biology from University of Southern California.
? Associate Professor in Orthodontics, Oral and Maxillofacial Surgery and Basic Sciences, Ostrow School of Dentistry, University of Southern California.
? Researcher at the Center for Craniofacial Molecular Biology.
? Director of Craniofacial Orthodontic Fellowship, Children?s Hospital Los Angeles.
? Staff orthodontist, USC?Los Angeles County Hospital.
? Diplomate, American Board of Orthodontists.
An evaluation of the influence of gingival display level in the smile esthetics
Objective: The aim of this study was to evaluate the influence of the amount of gingival display on smile esthetics.
Methods: Two extraoral photographs were used: One of the close-up smile and one frontal view of the smiling face of four individuals (one Caucasian and one Afro-Brazilian man, and one Caucasian and one Afro-Brazilian woman). The photographs were manipulated in a computer and five images were created for each original photograph with different degrees of gingival display: 0 mm, 1 mm, 3 mm, 5 mm and 7 mm. Then the images were evaluated by 60 individuals who assigned a score from zero to ten to each image on a visual analogue scale.
Results and Conclusions: Statistical analysis and results showed that levels of gingival display equivalent to 0 mm and 1 mm received the highest mean scores, i.e., 6.6 and 6.2, respectively, and showed no statistical difference between them (p>0.05). Gingival displays of 3 mm, 5 mm and 7 mm received lower, decreasing scores of 5.0, 3.5 and 2.9, respectively, without any statistical difference between levels 5 mm and 7 mm (p>0.05). Furthermore, the use of close-up photographs of the smile or frontal view photographs of the smiling face showed no statistical difference (p>0.05).
Dentoskeletal changes in Class II malocclusion patients after treatment with the Twin Block functional appliance
Objective: This prospective clinical study evaluated dentoskeletal changes in Class II malocclusion patients after treatment with the Twin Block functional appliance.
Methods: The treatment group consisted of 19 subjects (mean age 9.5 years) and the control group consisted of 19 subjects (mean age 9.9 years) situated before pubertal growth spurt. Unpaired Student?s t test showed the sample homogeneity at the beginning of the study. Initial (T1) and one year follow-up (T2) cephalometric radiographs were obtained for all subjects. Wilcoxon test and Mann Whitney test were used to evaluate changes intra and inter groups from T1 to T2.
Results: A Class I molar relationship was achieved in 15 subjects of the treated group while no modification occurred in the control group. No significant effect was observed either in the maxilla or in the vertical pattern. A significant increase in total mandibular length and an anterior displacement of the mandibular position occurred in the treated group (p<0.05) as well as an overjet reduction, influenced by significant upper incisor retroclination and lower incisor proclination (p<0.05).
Conclusions: Class II treatment with the Twin Block appliance in Brazilian patients showed skeletal and dental effects, including increase in mandibular length and incisors compensation, respectively.
Relapse of maxillary anterior crowding in Class I and Class II malocclusion treated orthodontically without extractions
Objective: The present study aimed to retrospectively compare the postretention stability of maxillary anterior incisors alignment in Class I and Class II patients.
Method: Sample comprised 38 patients of both genders, treated with no extraction and Edgewise mechanics, divided into two groups: Group 1 comprised 19 patients, at a mean age of 13.06 years, with Class I malocclusion and initial maxillary anterior crowding greater than 3 mm. Group 2 comprised 19 patients, at a mean age of 12.54 years, with Class II malocclusion, and also with an initial maxillary anterior crowding greater than 3 mm. In the dental casts of pretreatment, posttreatment and postretention, the Little irregularity index, intercanine width and width between first and second premolars, intermolar width and maxillary arch length were measured. For intragroup comparison among the three evaluation times the one-way ANOVA was used followed by Tukey test. Intergroup comparison was performed by independent t test. To verify the presence of correlation, the Pearson correlation test was used.
Results: Results evidenced greater stability of treatment in Group 2 (Class II), because during the postretention period, a smaller relapse of maxillary anterior crowding in Group 2 (0.80 mm) than in Group 1 (1.67 mm) was observed.
Conclusion: It was concluded that treatment of maxillary anterior crowding is more stable in Class II malocclusion than in Class I malocclusion.
Management of severe Class II malocclusion with sequential removable functional and orthodontic appliances: A case for MOrthRCSEd** examination
Objective: The following case report documented a 11 year old Chinese girl with 11 mm overjet treated by a phase I 12-month growth modification therapy using Twin Block appliance with Hyrax palatal expander and high-pull headgear in a stepwise mandibular advancement protocol followed by a phase II preadjusted Edgewise appliance therapy. It is one of the cases submitted for the Membership of Orthodontics Examination of the Royal College of Surgeons of Edinburgh.
A method to re-treat the relapse of dental misalignment
Electromyographic analysis of the orbicularis oris muscle in youngsters with Class II, Division 1 and normal occlusion
Aim: The purpose of this study was to make an electromyographic comparison of the action potentials of the upper and lower segments of the orbicularis oris muscle, bilaterally, in youngsters with Class II, Division 1 malocclusion and youngsters with normal occlusion in order to verify whether or not there is a difference between the two groups with regard to the electromyographic activity that occurs.
Methods: The sample consisted of 50 girls, in the age-range from 8 to 10 years, with no previous orthodontic treatment, divided into two groups: 25 with Class II, Division 1 malocclusion and 25 with normal occlusion. Electromyographic signals of the orbicularis oris muscle were acquired using Ag/AgCl surface electrodes. Muscle activity was recorded in the resting position, in the isometric contraction and in the isotonic contraction and the Root Mean Square (RMS) values of each movement were determined. The data collected were submitted to statistical analyses of variance and Tukey test (?=0.05).
Results: The results showed that there was a difference in electromyographic activity between the young girls with Class II, Division 1 malocclusion and those with normal occlusion. Muscle activity was higher in the girls with malocclusion than in those with normal occlusion.
Conclusion: This suggests lower competence of the orbicularis oris muscle in the girls with Class II, Division 1 malocclusion.
Comparative cephalometric study of dentofacial patterns of individuals with normal occlusion and Angle malocclusions
Effects of nickel-titanium and stainless steel leveling wires on the position of mandibular incisors
Method: The sample consisted of 36 individuals of both genders, Brazilian Caucasians with mean initial age of 15 years and 5 months with Class I and Class II malocclusions, divided into two groups. In Group 1 (n=17) leveling was performed with Sequence 1, comprised of three different wire cross-sections: 0.016-in and 0.019 x 0.025-in heat-activated NiTi wires and 0.019 x 0.025-in stainless steel wires. In Group 2 (n=19) Sequence 2 was tested using only stainless steel wires (0.014-in, 0.016-in, 0.018-in, 0.020-in and 0.019 x 0,025-in) with passive torque in the mandibular incisors. Data were collected using computerized cephalometry and compared using Student?s t-test with 5% significance level.
Results: In Group 1, mandibular incisors were inclined lingually although only the crowns showed significant movement (1.6 mm). In Group 2, mandibular incisors remained stable. No vertical changes were noted in either group.
Conclusions: Sequence 2 yielded better mandibular incisor control with no changes in their initial positions, while Sequence 1 allowed torques in the bracket prescription to be expressed, leading to the lingual inclination of these teeth. Treatment length was shorter when Sequence 1 was used. The evaluated biomechanic variations presented advantages and disadvantages that should be known and considered by the orthodontist during treatment planning.
Cephalometric analysis of the upper airways of Class III patients subjected to orthosurgical treatment
Orthognathic surgery. Mandibular setback. Airways. Oropharynx. Hypopharynx.
Methods: Immediate lateral preoperative and postoperative cephalometric radiographs of 17 Class III patients were evaluated. Measurements of airway space (AS) diameter were taken in the sagittal plane in the hypopharyngeal and oropharyngeal regions, and changes in hyoid bone position were also recorded. Paired t-test and Pearson?s coefficient were applied seeking for potential associations between skeletal and AS changes.
Results: Significant AS reduction was noted in the hypopharyngeal region (mean= 3.10 mm, p= 0.024). The hyoid bone was displaced inferiorly and posteriorly, thereby reducing its distance to the anterior mandibular region. No quantitative correlation could be established between anteroposterior AS reduction and mandibular setback. However, there was a strong correlation between initial AS diameter and the amount of reduction observed in the hypopharynx, but only moderate correlation with the oropharynx.
Conclusions: Mandibular setback can cause significant UA narrowing, especially in the inferior-most portion (hypopharynx). Therefore, special attention should be given to UA evaluation when formulating an orthosurgical treatment plan since the potential deleterious effects of these changes on functions of the patients should not be overlooked.
Stress distribution in a photoelastic model resulting from intrusion of mandibular incisors using Ricketts utility arch
Clinical and radiographic guidelines to predict pubertal growth spurt
Conclusion: Such information provide opportunities to increment the diagnosis and prognosis of these cases and in making planning decisions, treatment evolution and the retention phase, mainly for those patients presenting malocclusions associated to skeletal disharmonies.
Shear bond strength of composites using an adhesion booster
Objective: To evaluate the shear strength of two composites (Transbond XT and Concise) using an adhesion booster (Ortho Primer).
Methods: The sample consisted of 90 bovine incisors divided into six groups (n=15). All teeth were subjected to prophylaxis with pumice and enamel etching with phosphoric acid. Transbond XT was used conventionally in Group I. Group II was handled similarly to Group I, except that Ortho Primer was applied instead of XT Primer. After etching, the enamel in Group III was contaminated with saliva, Ortho Primer was then applied and bonding performed using Transbond XT. In Group IV, Concise was used conventionally. Group V was handled similarly to Group IV, except that Ortho Primer was applied instead of the fluid resin. After etching, the enamel in Group VI was contaminated with saliva, Ortho Primer was then applied and bonding performed using Concise. The specimens were stored in distilled water at 37 ºC for 24 hours and subjected to shear strength testing. Data were analyzed with ANOVA and Tukey?s test (5%).
Results: Bond strength in Group IV was statistically higher than in Groups II, III and VI (p<0.05). No statistically significant differences were found among Groups I, IV and V, and between I, II, III and VI (p>0.05). When used conventionally, both Transbond XT and Concise yielded the highest bond strength values. When applied to dry enamel, Ortho Primer acted effectively as a bonding agent for the composites under evaluation. When applied to contaminated enamel, Concise yielded low bond strength.
Influence of gingival exposure on the smile esthetics*
Methods: Photographs of smiling faces of a male and a female subject were manipulated on the computer with different gingival exposure levels, ranging from 4 mm of gingival exposure to 4 mm of upper lip incisor coverage. The photographs were printed in actual size of the face, and randomly analyzed by 30 orthodontists, 30 clinicians and 30 laypersons. The faces were rated as very poor, poor, regular, good and very good according to the smile attractiveness.
Results: The most attractive female smile, judged by the orthodontists, clinicians and laypersons, was the one where the upper lip rests on the gingival margin of the upper incisor, showing the whole incisor crown (P?0.05). For the male subject, the most attractive smile according to laypersons, was the one with the upper lip resting on the gingival margin of the crown of the maxillary incisor; while orthodontists and clinicians considered both the upper lip on the gingival margin of the maxillary incisor?s crown and 2 mm upper lip incisor coverage as the most esthetics (P?0.05).
Conclusion: Smile attractiveness is influenced by the gingival exposure, and different opinions are observed among orthodontists, clinicians and laypersons.
Comparative analysis of rapid maxillary expansion using three brands of fan-type expander screw: Laboratory trial using typodont
Cleft lip and palate. Expansion screw. Rapid maxillary expansion.
Objective: To evaluate the expansion pattern of three brands of fan-type expander screws to correct transverse deficiencies.
Methods: Eighteen expansions on typodonts were performed with 6 simulations for each group: G1 - Dentaurum® screw; G2 ? Leone® screw; and G3 ? Morelli® screw. For each trial 13 activations of 2/4 of a turn each were made with a 5.2 mm screw opening. Measurements were made at baseline (T1), after half of the activations (T2) and at the end of the trial (T3). A caliper was used to make the following measurements: Inter-first premolars (IP1), inter-second premolars (IP2) and intermolar (IM) widths and arch length (AL). The Kolmogorov- Smirnov, Tukey, Friedman and ANOVA tests were used to analyze data.
Results: All groups had a ?V? shaped opening pattern and the greater expansion was found in the anterior region of the arch, which was more evident in the G3 (29.58% in IP1 and 9.73% in IM). The increase in AL was similar in G1 and G3 (+12.65% and +12.13%) and the lowest value was found in G2 (+8.23%).
Conclusions: All the fan-type expander screws used in this study may be used to treat dental arch transverse deficiencies. However, the use of the Morelli screw resulted in a greater opening in the anterior region than in the posterior region, an important characteristic in the treatment of cleft lip and palate patients. Further clinical studies should be conducted to confirm these findings.
Profile evaluation of orthodontic professionals as for their legal actions
Objective: Evaluate the legal actions and behavior in the doctor/patient relationship, used by dental surgeons practicing orthodontics.
Methods: The population sample of the present study consisted of dental surgeons, active in the field of orthodontics, and registered with Dental Press Publishing Company ? Maringá/PR, Brazil, with a total sample size of 525 professionals. The research was conducted using a 17-question survey forwarded to these professionals.
Results and Conclusions: The majority of participants in our study are specialized in orthodontics; 75% of professionals use some sort of contract at the office/clinic; 73.7% of professionals periodically request maintenance X-rays; a large percentage of professionals (58.9%) keep patient records on file for life. The interviewed professionals demonstrate good knowledge of the Brazilian Code of Ethics in Dentistry, especially of Chapter XIV ? on Communication.
Serial extraction: Variables associated to the extraction of premolars
Objective: To determine the frequency of patients who require extraction of permanent premolars among those treated with extraction of deciduous teeth for the correction of incisor crowding in the mixed dentition and analyze possible associated variables.
Methods: The sample was composed of orthodontic records of 70 patients with permanent dentition whose treatment had begun in the mixed dentition phase and involved serial extraction. All records were analyzed by a single examiner to determine whether serial extraction had been performed with extraction of permanent teeth or only deciduous teeth. Associations were investigated between extraction of permanent teeth and lateral facial pattern, sagittal relationship of the dental arches, incisor-mandibular plane angle, size proportion of mandibular second molar/retromolar space, mechanics for space control and tooth-arch size discrepancy (Fisher?s exact test for categorical variables and logistic regression for numeric variables, p<0.05).
Results: Among the patients who had been treated with extraction of deciduous teeth, 70% required the extraction of permanent teeth. The statistical analysis revealed no significant associations between the analyzed variables and the need for permanent tooth extraction, with the exception of tooth-arch size discrepancy.
Conclusion: Tooth-arch size discrepancy was the main factor determining premolar extraction in a serial extraction program.
Effects evaluation of remaining resin removal (three modes) on enamel surface after bracket debonding
Introduction: An appropriate selection of instruments is essential to perform a correct debonding technique, by properly removing orthodontic brackets and the remaining resin.
Objective: The aim of this study was to evaluate three methods of remaining resin removal on enamel surface after bracket debonding, by means of Scanning Electron Microscopy (SEM).
Methods: Eighteen bovine incisors were selected and divided into three groups (A, B and C) of six teeth each. Before bracket bonding, epoxy resin casts were obtained by impression of the teeth with addition silicon, in order to register baseline enamel characteristics and representing the control group. The methods for remaining resin removal were: Group A ? gross and medium granulation Soflex discs; Group B ? carbide bur in low-speed; Group C ? carbide bur in high-speed. Soflex polishing system fine and ultrafine granulation discs were used for Group A, rubber tips for Groups B and C, and polishing paste for all groups. After polishing, impression of teeth were taken and casts were analyzed by means of SEM. The baseline enamel characteristics (Control Group) were compared to the final aspect of enamel to determine the method that generated less enamel abrasion.
Results and Conclusion: The remaining resin removal by carbide bur in low-rotation, and enamel polished with rubber tips followed by polishing paste produced the smaller damage to the enamel.
Comparative assessment of anterior spacing in Japanese-Brazilian and Caucasian children in the deciduous dentition
Objective: To carry out a comparative evaluation of prevalence of anterior spacing characteristics in Japanese-Brazilian and Caucasian children in the deciduous dentition.
Methods: Two samples of children aged 2-6 years were selected: 405 Japanese-Brazilians from 36 schools in the State of São Paulo and 510 Caucasian children from 11 public institutions in São Paulo city. Spacing features in the maxillary and mandibular arches were assigned to four categories: Generalized spacing, only primate spaces, no spacing and crowding. Logistic regression was used to analyze the effect of age, gender and ethnic group on the prevalence of the occlusal characteristics (? = 0.05).
Results: In Japanese- Brazilians, generalized spacing was the most prevalent characteristic in the maxillary (46.2%) and mandibular (53.3%) arches. The frequency of primate spaces was higher in the maxillary arch (28.2% versus 15.3%). Concerning no spacing (21.7% ? 26.4%) and crowding (4% ? 4.9%), the variation between arches was relatively small. In Caucasian children, no spacing and exclusive presence of primate spaces showed distributions similar to that observed in Japanese-Brazilians. Generalized spacing was diagnosed in approximately 50% of the arches. Crowding prevalence was higher in the mandibular arch (12.8% versus 3.9%). The regression model adjusted for crowding prevalence was the only significant one. Only the ethnical factor was significant (p<0.001).
Conclusions: It may be suggested that anterior spacing features in the deciduous dentition would not be influenced by age or gender. Nevertheless, Caucasian children would have 2.8 times more chances of presenting crowding in the mandibular arch, in comparison with Japanese-Brazilians.