Is there any difference between conventional, passive and active self-ligating brackets? A systematic review and network meta-analysis

AIM

To test the null hypothesis that there was no difference in treatment efficiency between therapies undertaken with conventional (CBs), passive self-ligating (PSLBs) or active self-ligating (ASLBs) brackets.

MATERIALS AND METHODS

An electronic search was performed in 3 data bases (Pubmed, Web of Science, Cochrane Library) from their origin up to January 2019. Additional references were hand searched. Search was strictly restricted to randomized controlled trials (RCTs) and split-mouth design studies (SMDs). RCTs and SMDs were initially processed separately and subsequently combined in a network meta-analysis. The following variables were evaluated: treatment duration, number of visits, occlusal outcomes, alignment rate, transverse arch dimensional changes, incisor position modification, rate of space closure, anchorage loss, bond failure, root resorption, perception of discomfort during the initial phase of alignment, time to ligate in or to untie an archwire, periodontal variables, quality of life.

RESULTS

On 229 papers, 30 RCTs and 9 SMDs were finally included in this study. Out of 85 comparisons, 16 only revealed statistically significant differences. It was quicker to untie and ligate an 0.014 NiTi arch from/in 6 ASLBs anterior ceramic brackets compared to 6 ceramic CBs. It was also more painful to insert and remove an 0.019×0.025 SS wire in/from PSLB's brackets compared to CB's attachments. Compared to conventional brackets, there was less maxillary incisor proclination with PSLBs in non-extraction cases. Moreover, there was less bleeding on probing 4-5 weeks after bonding with PSLBs compared to CBs brackets. The only significant difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. The network meta-analysis revealed that IMPA was greater in extractions cases with CBs compared with both ASLBs (+2,5°) and PSLBs (+1,6°).

CONCLUSIONS

The vast majority of the studied variables did not show any significant differences between the three types of brackets. The most significant findings were that it was quicker to insert and remove archwires from ASLBs compared to CBs, and it was more painful to insert and remove an 0.019×0.025" stainless steel wire in/from PSLBs compared to CBs. The major difference between ASLBs and PSLBs was that alignment was 10 days faster with active self-ligating braces compared with passive self-ligating braces even if treatment duration between ASLBs and PSLBs was not significantly different. Most of the claims put forward by the suppliers were not substantiated by our network meta-analysis.

How do general dental practitioners perceive and deal with orthodontic bonded retainers?

INTRODUCTION

Long-term follow-up and management of orthodontic bonded retainers require a strong collaboration between orthodontists and general dental practitioners (GDPs). This study aimed to evaluate if Eastern French GDPs were aware of bonded retainers' complications and side effects and if they were willing to take part in their long-term follow-up.

METHODS

Two-hundred and eighteen randomly selected GDPs were invited to answer an online questionnaire. The initial sections covered their experience and management with bonded retainers. In the final sections, GDPs were asked their opinion on the responsibility for long-term follow-up of patients wearing fixed retainers and on the mutual communication between orthodontists and GDPs. Statistical analysis involved descriptive statistics and Fisher exact tests.

RESULTS

Response rate was 32.6% (n = 71). The vast majority of GDPs were familiar with loose retainers, but only 45.2% were willing to repair them. Respondents offering orthodontic services on a regular basis were more likely to insert retainers and repair loose or broken retainers (P < 0.001). Approximately 18.6% of GDPs were aware of third-order side effects encountered with unintentionally active retainers bonded to all 6 anterior teeth. For 88.8% of GDPs, permanent retention was justified, whereas 90% of the dentists refused to be responsible for long-term supervision of fixed retainers. In addition, 67.1% were interested in further training on orthodontic retention, and 92.9% would appreciate clinical guidelines.

CONCLUSIONS

Knowledge about the harmful side effects of bonded retainers was evaluated as insufficient among surveyed GDPs. Long-term follow-up of patients wearing bonded retainers raises issues that should be addressed globally by enhancing mutual communication, practitioners' education, and patients' involvement.

Relationship between European postgraduate programme accreditation and national research output: The case of the Network of Erasmus-Based European Orthodontic Postgraduate Programmes (NEBEOP) in orthodontics. A bibliometric study

AIMS

To assess in each European country the correlation between the number of Network of Erasmus-Based European Orthodontic Postgraduate Programmes (NEBEOP) members and orthodontic research activity. Secondary objectives were to describe and quantify Europe's orthodontic research.

MATERIALS AND METHODS

Articles published between 2014 and 2018 in 4 major orthodontic journals (American Journal of Orthodontics and Dentofacial Orthopedics, European Journal of Orthodontics, The Angle Orthodontist, Orthodontics and Craniofacial Research) and oral presentation abstracts of five European Orthodontic Society (EOS) congresses were analysed. For each European country, the total number of orthodontic programmes and NEBEOP memberships were collected. Descriptive statistics were performed, and Spearman correlation coefficients and risk ratios were calculated.

RESULTS

2039 articles and 261 oral presentation abstracts were included. Correlation coefficients between national number of publications, oral presentations, sum of these, all adjusted for population, and number of NEBEOP members in each country were 0.64, 0.65 and 0.62, respectively. Risk ratios were all above 1 and statistically significant for number of NEBEOP memberships per country, indicating positive associations with national orthodontic research productivity. Europe accounted for 30.5% of publications and 68.6% of oral presentations at EOS congresses during this period. European orthodontic research was not evenly distributed, since 9 countries were responsible for around 80% of the output.

CONCLUSIONS

A positive association was found between number of NEBEOP programmes and national research activity. These results could be an additional argument to support similar pan-European initiatives and guidelines for postgraduate education, not only in orthodontics but in all other dental specialties.

Prevalence and risk factors of root resorption of adjacent teeth in maxillary canine impaction, among untreated children and adolescents

OBJECTIVES

The aim of this retrospective study was to assess in maxillary canine impaction cases both the prevalence of root resorption of adjacent teeth among untreated children and adolescents, and its associated risk factors.

SUBJECTS AND METHODS

Sixty subjects (mean age 12.2 years; SD 1.9; range 8-17 years) with 83 displaced maxillary canines and without any past or ongoing orthodontic treatment were included in this study. The presence of root resorption was evaluated on images from a single cone beam computed tomography (CBCT) unit. Potential risk factors were measured on the CBCT images and on panoramic reconstructions of the 3D data sets. The sample was characterized by descriptive statistics and multiple logistic regressions were performed to predict root resorption.

RESULTS

Root resorption of at least one adjacent tooth was detected in 67.5 per cent of the affected quadrants. It was found that 55.7 per cent of the lateral incisors, 8.4 per cent of the central incisors, and 19.5 per cent of first premolars were resorbed. Of the detected resorptions, 71.7 per cent were considered slight, 14.9 per cent moderate, and 13.4 per cent severe. Contact between the displaced canine(s) and the adjacent teeth roots was the only identified statistically significant risk factor, all teeth being considered (odds ratio [OR] = 18.7, 95% confidence interval: 2.26-756, P < 0.01). An enlarged canine dental follicle, a peg upper lateral, or an upper lateral agenesis were not significantly associated with root resorption of adjacent teeth, nor were age nor gender.

CONCLUSIONS

Root resorption of adjacent teeth was detected in more than two-thirds of a sample of sixty untreated children and adolescents.

First premolar extractions in an adolescent presenting a Class I biprotrusion malocclusion with skeletal Class II: A case report

This case report shows the orthodontic treatment of four first premolar extractions of a 14-year-old teenager presenting a dental Class I malocclusion with a severe retrognathic mandible. It reflects conflicting views on objectives between the orthodontist who takes into account the facial balance and the patient who only desires a tooth alignment.

[Aesthetic perception of the vertical position of the incisal edges of the maxillary lateral incisors in the smile arch]

INTRODUCTION

The aim of this study is to assess the attractiveness in the smile arch of different vertical positions of the incisal edges of the maxillary lateral incisors.

MATERIAL AND METHODS

A frontal photograph of a Caucasian woman's smile was digitally modified to obtain an image with the incisal edges of the maxillary lateral incisors symmetrically tangent to the smile arch. These incisal edges were then moved vertically by 0.5 mm increments. The value was considered positive for an occlusal shift and negative for a gingival shift. Four other images were obtained by moving the incisal edges from +0.5 mm to -1.5 mm. The five images were rated on a visual analog scale by three groups of evaluators: orthodontists, dentists and laypersons. A statistical analysis was performed.

RESULTS

Laypersons preferred first lateral incisors tangent to the smile arch, second a +0.5 mm shift, and third a -0.5 mm shift. Orthodontists and dentists preferred first a -0.5 mm shift and second a null shift.

CONCLUSIONS

The aesthetic perception of the smile, as regard to the vertical relationships between the incisal edges of the anterior teeth, differs between laypersons and professionals but remains homogenous between orthodontists and dentists. The most consensual aesthetic situation, from both professionals' and laypersons' points of view, is the geometry in which the incisal edges of the maxillary lateral incisors are tangent to the smile arch.

[Beauty judgment: review of the literature]

Esthetic judgments are surely subjective, but as surely, that does not preclude them being studied objectively through rigorous scientific methods. The factual basis of a science of esthetics is not to settle whether some person or image is "objectively beautiful" but rather to determine whether some representative set or sets of individuals judge or experience him/her/it as beautiful or unattractive. The aim of this paper is to review the definitional, theoretical and methodological aspects pertaining to the perception of facial/dental attractiveness by a group of representative individuals. The first part lays down the basic principles of the perception of facial/dental attractiveness: the perception involves a jury, a field of investigation and a test providing quantitative data; the following general determinants of beauty perception are reviewed: the average morphology, the judge's cultural background, the numerology, the judge's ethnical origin. Indirect determinants are the dentition, the osseous architecture and the muscular envelope. Some disruptive factors might alter the judges' facial perception. They might be qualified as either peripheral to the face or psycho-social factors. Peripheral factors include hair style and color, skin hue, wrinkles, lips color... Psycho-social factors cover the personality of the subject being evaluated, his/her intelligence or behavior. The second part deals specifically with the methodology used to determine facial attractiveness and to correlate this latter with a specific morphology. Typically such a study aims to determine average esthetic preferences for some set of visual displays among a particular jury, given a specific task to judge esthetic quality or qualities. The sample being studied, the displays, the jury or jurys, the rating procedure must all be specified prior to collecting data. A specific emphasis will be given to the rating process and the associated morphometrics, the ultimate goal being to discriminate morphologies judged as attractive among our patients.

[Is the shape memory effect a reality for 35° Copper Ni-Ti(®)? Study by means of differential scanning calorimetry]

INTRODUCTION

Copper-nickel-titanium alloys are supposed to deliver a shape memory effect: when they are brought to a low temperature phase and subjected to a plastic deformation, they should recover their initial shape by simple heating. Nickel-titanium alloys can display different crystallographic phases: martensite, austenite and an inconstant intermediate R-phase. The shape memory effect is generally associated with the transition from martensite to austenite but it could also accompany the transition from R-phase to austenite. Since oral temperatures are not compatible with a fully martensitic alloy, this study aims, for 35° Copper Ni-Ti(®), to assess the R-phase presence at oral temperatures and to verify the possibility of using the R-phase shape memory effect under clinical conditions.

MATERIALS AND METHODS

Thirty consecutive 35° Copper Ni-Ti(®) archwires from two different batches were examined by differential scanning calorimetry with partial cycles limited to temperatures encountered within the oral cavity (from 0 °C to 50 °C). The presence of an intermediate crystallographic phase was assessed on the thermograms. The transformation temperatures were determined and the two batches were compared using the Mann-Whitney U Test.

RESULTS

Upon heating, all wires transformed directly from martensite to austenite. Af (mean  = 33.5 °C, SD  = 0.8 °C) was generally below the temperature stated by the manufacturer and a statistically significant difference (p ≤ 0.01) was found between the two batches.

CONCLUSIONS

No R-phase was detected and transformation temperatures were not constant. This study questions the supposed shape memory effect displayed by 35° Copper Ni-Ti(®) wires under clinical conditions.

[Orthodontics founded on "proof" or therapeutic decision making based on the literature]

Faced to an abundant literature and to various clinical situations, practitioners are nowadays invited to implement an evidence based approach. This methodology, initially developed in Canada in the 80's, is getting widely used and is perfectly suited for Orthodontics and particularly for the evaluation of interceptive treatments. It is defined as the conscentious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. This approach, which requires four different steps, will initially be presented. A methodological guide that allows to grade the evidence among different research protocols, will then be introduced. At the top of the hierarchy, randomized clinical trials have shown to be the best tools available to evaluate treatment efficiency. Different research designs are finally put forward to evaluate interceptive treatments.

Collagenase synthesis by cloned rabbit pulp cells--molecular and immunological identity of pulp cell and fibroblast enzyme

Cultures of cloned rabbit pulp (RP) cells without stimulation produced collagenase of a concentration as high as reference rabbit skin fibroblast cultures which were stimulated with phorbol myristate acetate (PMA, 100 ng/ml). The RP cell collagenase was compared with reference fibroblast collagenase in Western blot analysis using monoclonal antibodies prepared against RP cell collagenase and a polyclonal antibody prepared against rabbit fibroblast collagenase. Both enzyme preparations revealed, with either antibody, identical bands of approximate molecular masses 57,000, 52,500, and 45,000. These antibody preparations variously inhibited RP cell collagenase activity. Intracellular collagenase in RP cells in culture was demonstrated by the indirect immunofluorescence antibody technique using polyclonal anti-fibroblast collagenase antibody. RNA samples from RP cells hybridized with rabbit fibroblast collagenase cDNA (clone H9) and showed a distinct band at 2.7 kb. Both control and PMA-stimulated RP cells and PMA-stimulated reference skin fibroblasts demonstrated strong cytoplasmic hybridization between H9 and collagenase mRNA. The results indicate that RP cell collagenase is identical to rabbit fibroblast collagenase, and that the RP cell line provides a useful in vitro reference system for the study of collagenolysis in the rabbit model.