Contributions of Digital Simulation to Orthodontic Therapeutic Decision-Making: A Case Report

Adult orthodontics aims to achieve optimal functional and aesthetic corrections. However, for several reasons, some patients will wish to benefit from a limited treatment where only certain aspects of a malocclusion will be corrected. In these clinical situations, the therapeutic objectives must be adjusted to the individual needs of the patient insofar as they can bring them real benefits. The use of digital technology makes it possible to study the therapeutic possibilities better and visualize the occlusal results before choosing the best therapeutic approach, especially in cases requiring customization. The aim of this clinical case report is to illustrate the orthodontic compromise made after the analysis of the digital setup in an adult patient who presented with a class III malocclusion but refused orthodontic-surgical therapy and requested an alternative treatment.

Accuracy of hard and soft tissue prediction using three-dimensional simulation software in bimaxillary osteotomies: A systematic review

INTRODUCTION

Orthognathic surgery is considered nowadays as a revolutionary treatment option for treating skeletal discrepancies and severe malocclusions in the sagittal, vertical and transverse dimensions. This surgery allows both the restoration of facial harmony and the achievement of satisfactory dental occlusion. The technology of computer-assisted surgeries including virtual surgical simulation programs and planning software greatly contributes to providing a three-dimensional simulation and precise mobilization of the maxilla and/or mandible, thus allowing the prediction of the final outcome in soft tissues. This study aims to systematically review the available scientific literature about the accuracy of the hard and soft tissue predictions delivered by the many promoted three-dimensional simulation software.

MATERIAL AND METHODS

An electronic search was conducted on various databases: Medline via PubMed, The Cochrane Library, EBSCO-host, and Web of Science. The search was established on a well-defined research question following PICO principle: population, intervention, comparator and outcome. Search evaluation and the assessment of risk of bias were undertaken in each study following its type and design.

RESULTS

Fifteen studies were included for qualitative analysis. Seven studies evaluated the accuracy of soft tissue prediction, seven focused more on the accuracy of hard tissue and one study assessed both hard and soft tissue prediction accuracy delivered by the simulation software. Moreover, three studies were judged to be low risk and four were classified as high risk. Included studies revealed that hard tissue prediction is highly accurate and reliable, leading to clinically acceptable results. Yet, soft tissue prediction is unclear due to various factors that bias its results. Caution should therefore be taken when providing information about the soft tissue planning to patients.

CONCLUSIONS

Computer assisted 3D simulation protocols allow for more precise repositioning of the maxilla and/or mandible compared to conventional 2D methods. However, 3D soft tissue prediction using simulation software remains less accurate, especially in the labial region.

Large-scale seasonal forecasts of river discharge by coupling local and global datasets with a stacked neural network: Case for the Loire River system

Accurate prediction of river discharge is critical for a wide range of sectors, from human activities to environmental hazard management, especially in the face of increasing demand for water resources and climate change. To address this need, a multivariate model that incorporates both local and global data sources, including river and piezometer gauges, sea level, and climate parameters. By employing phase shift analysis, the model optimizes correlations between the target discharge and 12 parameters related to hydrologic and climatic systems, all sampled daily. In addition, a stacked LSTM - a more complex neural network architecture - is used to improve information extraction ability. Exploring river dynamics in the Loire-Bretagne basin and its surroundings, the investigation delves into predictions in daily time steps for one, three, and six months ahead. The resulting forecast features high accuracy and efficiency in predicting river discharge fluctuations, showcasing superior performance in forecasting drought periods over flood peaks. A detailed examination on data used highlights the significance of both local and global datasets in predicting river discharge, where the former dictates short-term predictions, while the latter drives long-range forecasts. Seasonally extended forecasting confirms a strong connection between the forecast leading time and the shift in data correlation, with lower correlation at a lag of 3 months due to seasonal changes affecting forecast quality, compensated by a higher correlation at a longer lag of 6 months. Such mutual effect in this multi-time-step forecasting improves the predictive quality of a six-month horizon, thus encourages progress in long-term prediction to a seasonal scale. The research establishes a practical foundation for effectively utilizing big data to leverage long-term forecasting of environmental dynamics.

Oral and dental abnormalities in Coffin Siris syndrome : A new case report

INTRODUCTION

Coffin-Siris Syndrome (CSS) is a rare genetic disorder of unknown etiology. It combines digital-ungual abnormalities, facial dysmorphism, developmental and intellectual delay, and other organ-system abnormalities. Oral and dental anomalies are rarer.

CASE REPORT

8-year-old boy with clinical diagnosis of CSS presented facial dysmorphism, sparse hair, a flat and wide nose, absence of nails on 3rd and 5th fingers of the right hand and 3rd and 4th fingers of the left hand, malformation of the feet, toes with nail hypoplasia. Oral and dental anomalies included : bilateral complete cleft lip and palate, delayed eruption of permanent teeth, presence of supernumerary tooth and taurodontism in the first permanent molars.

CONCLUSION

Early diagnosis of oral problems and regular follow-up in dentist are necessary to promote good oral health and improve the patient's quality of life.

Perception of smile aesthetics between orthodontists and Moroccan patients

Introduction

One of the main goals of orthodontic management is to achieve a beautiful smile. However, beauty has both objective and subjective dimensions. This study aims to evaluate the factors that affect the perception of the smile in patients consulting for orthodontic treatment about the vision of their practitioners.

Materials and Methods

Fifty orthodontic patients and 30 orthodontists evaluated the degree of attractiveness of 16 photographs of the smile. Dental, gingival and labial parameters were used. Statistical analyses of the level of perception of each group were performed. The Student t-test and the Chi-square test were used to compare the attractive and unattractive smile parameters.

Results and Discussion

The perception of smile aesthetics between orthodontists and orthodontic patients has shown a significant difference (P < 0.05). Orthodontists were more analytical in judging variables like smile arc, alterations of the gingival display and the palatal inclination of the maxillary incisors.

Three-dimensional orthodontic anchorage management of impacted maxillary canines: A systematic review

Objectives:

Our work aims to provide scientific evidence by conducting a serious systematic review of the efficacy of three-dimensional (3D) anchorage devices for orthodontic traction of impacted maxillary canines.

Material and Methods:

An electronic search extending from 2012 to 2022, targeting mainly clinical trials was performed on the following databases PUBMED (MEDLINE), The Cochrane Library, SCIENCE DIRECT, EBSCO HOST DATABASES, and GOOGLE SCHOLAR. The search was established on a well-defined research question following the PICO principle: population, intervention, comparator, and outcome. Search evaluation and the assessment of the risk of bias (RoB) were undertaken in each study following its type and design.

Results:

Thirteen studies were included for qualitative analysis, with a low to moderate RoB. Ten studies used only heavy conventional palatal anchorage such as a fixed trans palatal arch (TPA), while one study used skeletal anchorage to manage the orthodontic traction of impacted maxillary canines. Two studies compared trans palatal arch and mini-screws efficiency to treat impacted maxillary canines.

Conclusion:

Studies proved that the trans palatal arch (TPA) presents a particular anchorage unpredictability in the sagittal, transversal, and vertical dimensions. Whereas, anchorage management using mini-screws proved to be very beneficial clinically; however, further studies must be implemented to evaluate the 3D efficacy of skeletal anchorage to place an impacted maxillary canine to its rightful position into the arch.

[Impact of incisor repositioning on the cephalometric position of points A and B]

Introduction

points A and B are bony landmarks used in cephalometric studies to assess sagittal ratio between maxilla and mandible. The purpose of this study is to assess the reliability of points A and B as bony landmarks, by investigating the role of incisor repositioning on their cephalometric position.

Method

superposition of cephalometric tracings at beginning and end of treatment of 30 patients without bone growth disorders, presenting with biproalveolia and having undergone orthodontic treatment with extraction of four first premolars was carried out to estimate changes in points A and B position. The significance threshold was set at 0.05.

Results

our study showed that the influence of orthodontic treatment on point A position was not statistically significant, while its influence on point B position was statistically significant (p= 0,01). Indeed, for every 1mm of incremental repositioning, point B moved back by 0.17mm.

Conclusion

incisor repositioning in the mandibular arch induces a change in the position of point B backwards.

Enamel protection after stripping procedures: An in vivo study

INTRODUCTION

Interproximal enamel reduction (IPR) is a clinical procedure that has been in use since the advent of non-extraction orthodontic techniques. However, such a procedure affects the surface condition of the enamel and may predispose patients to cavities and hypersensitivity. The use of a remineralizing agent is recommended to prevent these side effects. The objective of our study was to evaluate the evolution of stripped proximal dental surfaces after exposure to the oral environment for 4 months with and without fluoride protection.

MATERIALS AND METHODS

Our sample consisted of 14 premolars (PM) from 6 patients of the Dentofacial Orthopaedics Department of the Consultation and Dental Treatment Centre of Rabat (CDTC) who required orthodontic treatment with PM extraction and had given their informed consent. The teeth were divided into 5 groups: group 1: intact enamel; group 2: intact enamel+fluoride varnish+4-month oral exposure; group 3: IPR (manual and mechanized)+extraction; group 4: IPR (manual and mechanized) without varnish+4-month oral exposure; group 5: IPR (manual and mechanized)+fluoride varnish+4-month oral exposure. Proximal surfaces were subjected to qualitative analysis by scanning electron microscopy and quantitative analysis by Dispersive Energy Spectroscopy (DES) to quantify the percentage of mineral elements.

RESULTS

Exposure of stripped dental surfaces to the oral environment for 4 months with or without fluoride protection showed the persistence of surface irregularities caused by stripping. We noted an improvement in the percentage of mineral elements for both groups with and without fluoride protection. However, the percentages of calcium (Ca) and phosphorus (P) were close to that of intact enamel in the fluoride varnish group.

CONCLUSION

Protecting stripped surfaces with fluoride varnish could help preserve the integrity of the enamel surface by restoring some of the mineral elements lost during stripping.

In vivo enamel stripping: A macroscopic and microscopic analytical study

INTRODUCTION

Interdental stripping is often used in orthodontics to correct discrepancies of tooth shape or size. However, this procedure involves significant risks for the enamel. The roughness of the enamel surface might depend on the instruments used; it can lead to the accumulation of cariogenic plaque and periodontal problems. The main objective of our study was to evaluate the enamel surface condition after interproximal stripping in the mouth, by comparing different manual and mechanized enamel reduction protocols; on the other hand, the topography of the stripped area was observed to specify its location on the stripped proximal surfaces.

MATERIALS AND METHODS

An in vivo study was carried out: interdental stripping was performed in the mouths of patients undergoing orthodontic treatment and on healthy teeth intended for extraction for orthodontic or periodontal reasons. The sample was divided into four groups: in group 1, the distal faces were stripped with conventional single-sided diamond abrasive strips and non-stripped mesial faces (control faces); in group 2: the distal faces were stripped with the manual ContacEZ IRP Kit (single-sided abrasive files of different grain sizes) and non-stripped mesial faces (control faces); in group 3: the faces were stripped with ContacEZ IRP diamond discs attached to a handpiece and the mesial faces were not stripped (control faces); in group 4: the distal faces were stripped with the Intensiv Ortho-Strips mechanized system and the mesial faces were not stripped (control faces).

RESULTS

Our study showed that regardless of the type of stripping material used, the enamel surface showed some roughness with the presence of striations and grooves of different widths and depths. Our observations objectivised more regular and less roughened enamel surface conditions when using the Intensiv oscillating files. Manual instruments (abrasive strips and files) have shown rougher and more irregular surface conditions that may constitute a real risk of carious and periodontal disease. The macroscopic evaluation of the topography of the stripped area showed that there is great variability in the situation and extent of the stripped area in relation to several parameters.

CONCLUSION

The current mechanized instruments (oscillating files) provide enamel stripping with more comfort for the patient and the practitioner, and seem to produce a more regular and less harmful surface condition for the tooth and periodontium.

Fluoride induced corrosion affecting Titanium brackets: A systematic review

INTRODUCTION

A number of studies have been published regarding the behaviour of titanium inside the oral cavity or in a similar environment. Very often the results converge although they may on occasion be divergent. There appears to be a strong need for a systematic review because of this disparity, with a view to designing an experimental working method. Our study will attempt to analyse the various aspects of this problem. It will therefore focus on fluoride and its impact, as well as on the role it plays in corroding titanium orthodontic brackets (Ti) according to the synthesis and critical analysis drawn from literature.

METHODS

An exhaustive bibliography search was conducted in the following databases: PubMed, Science Direct and Cochrane Library using a search equation based on the following key-words: corrosion, titanium brackets and fluoride.

RESULTS

Out of 459 identified references, only 5 matched our inclusion criteria.

CONCLUSION

Although very few articles look into the impact of fluoride on titanium orthodontic brackets, one may conclude that in the presence of fluoride ions, resistance to corrosion of Ti attachments decreases in the presence of high fluoride concentrations and lengthy exposure to fluoride ions and an acid pH.

A predictive model of advancement genioplasty in Class III bimaxillary surgical cases

INTRODUCTION

The aim of our study was to try to standardize the surgeon's clinical sense in order to avoid revision surgery.

MATERIALS AND METHODS

Twenty-nine patients with skeletal Class III treated by bimaxillary surgery were selected according to inclusion and exclusion criteria. These patients were divided into two groups according to the type of surgery: Group 1 (G1): bimaxillary surgery alone, and Group 2 (G2): bimaxillary surgery with genioplasty. The study was conducted based on the presurgical (t₀) and postchirurgical (t₁) lateral cephalograms. The different changes were compared between the two groups using the Mann-Whitney Test. One way and multiple linear regression analyses were used to determine the variables influencing the amount of displacement of the chin fragment during the genioplasty procedure. The significance level was fixed at 0.05.

RESULTS

The labiomental profile was significantly more improved in group G2 (bimaxillary surgery with genioplasty), the aesthetic changes included the thickness increase of the lower labial sulcus and soft tissue pogonion, and also the reduction of the labiomental angle (P<0.05). Only the presurgical value of the labiomental angle would influence the amount of chin displacement. Starting from the regression analysis, we suggested a predictive equation allowing to predict this amount of displacement, based on the presurgical value of the labiomental angle.

CONCLUSION

The analysis of changes (specifically the aesthetic ones) between the two groups of patients, allowed the proposal of a model predicting the amount of chin displacement performed in genioplasty group, based on the presurgical parameters. This model could contribute to determine an indicative value for bimaxillary surgery with additional genioplasty.

A systematic review of orthodontic retention systems: The verdict

INTRODUCTION

Retention during both the active and passive phases of treatment has given rise to numerous publications concerning its efficacy, the range of systems available and its variability over time. There are currently many different retention protocols regularly used by orthodontists; however, their efficacy and duration are still subject to debate. There is as yet no consensus as to which retention protocol is the most effective or for how long the retention device needs to be worn. The aim of this research was to perform a systematic review of the scientific literature in order to evaluate the efficacy of the different retention systems and clinical protocols among those most widely used, so as to make recommendations beneficial to both patient and practitioner.

MATERIALS AND METHODS

A search of the literature was performed in the following databases: PubMed (MEDLINE), ScienceDirect and Cochrane Library. The search was limited to publications in English and French during the period 2006-2016.

RESULTS

Out of 1952 references initially identified, 17 articles corresponded to our inclusion criteria. The results show that: fixed retention is more effective than removable retainers for the maintenance of incisor alignment during the first six months of retention; there is no significant difference in efficacy between the different fixed retention systems; there is no significant difference in efficacy between the vacuum-formed systems and the Hawley retainer; part-time use of removable retainers (between 8-10h/day) is sufficient; the most widely used retention protocol combines a vacuum-formed splint or Hawley retainer in the upper arch with mandibular fixed retention.

CONCLUSION

Despite the large number of studies devoted to orthodontic retention only a few articles corresponded to the methodological criteria of bio statistical analysis. Also, on account of the variations in experimental protocols, the levels of proof relating to the efficacy of different systems are very weak. Research into this topic should first seek to normalize methods of analysis and then perform randomized controlled long-term trials to shed light on this problem.

Relationship between the curve of Spee and craniofacial variables: A regression analysis

INTRODUCTION

The aim of this regression analysis was to identify the determining factors, which impact the curve of Spee during its genesis, its therapeutic reconstruction, and its stability, within a continuously evolving craniofacial morphology throughout life.

MATERIAL AND METHODS

We selected a total of 107 patients, according to the inclusion criteria. A morphological and functional clinical examination was performed for each patient: plaster models, tracing of the curve of Spee, crowding, Angle's classification, overjet and overbite were thus recorded. Then, we made a cephalometric analysis based on the standardized lateral cephalograms. In the sagittal dimension, we measured the values of angles ANB, SNA, SNB, SND, I/i; and the following distances: AoBo, I/NA, i/NB, SE and SL. In the vertical dimension, we measured the values of angles FMA, GoGn/SN, the occlusal plane, and the following distances: SAr, ArD, Ar/Con, Con/Gn, GoPo, HFP, HFA and IF. The statistical analysis was performed using the SPSS software with a significance level of 0.05.

RESULTS

Our sample including 107 subjects was composed of 77 female patients (71.3%) and 30 male patients (27.8%) 7 hypodivergent patients (6.5%), 56 hyperdivergent patients (52.3%) and 44 normodivergent patients (41.1%). Patients' mean age was 19.35±5.95 years. The hypodivergent patients presented more pronounced curves of Spee compared to the normodivergent and the hyperdivergent populations; patients in skeletal Class I presented less pronounced curves of Spee compared to patients in skeletal Class II and Class III. These differences were non significant (P>0.05). The curve of Spee was positively and moderately correlated with Angle's classification, overjet, overbite, sellion-articulare distance, and breathing type (P<0.05). We found no correlation between age, gender and the other parameters included in the study with the curve of Spee (P>0.05). Seventy five percent (75%) of the hyperdivergent patients with an oral breathing presented an overbite of 3mm, which is quite excessive given the characteristics often admitted for this typology; this parameter could explain the overbite observed in the hyperdivergent population included in this study. For the multivariate analysis, the overbite and the sellion-articulare distance remained independently related to the curve of Spee according to the breathing type, Angle's classification, and overjet. This regression model explains 21.4% of the changes in the curve of Spee.

Topographic and chemical surface modifications to metal brackets after a period in the mouth

INTRODUCTION

In the current state of our knowledge, the effects of corrosion on the performance of orthodontic appliances and on patient health are far from clear. Awareness of these problems has led to a growing demand for nickel-free products. Titanium brackets were recently launched on the market as an alternative to stainless-steel brackets. However, the use of fluorides for caries prevention creates a risk of corrosion of these titanium appliances. The aim of this study is to examine the corrosion of stainless-steel and titanium brackets in clinical orthodontic use, focusing on the impact of fluorine.

METHODS

After approval by the ethics committee and the informed consent of the patients, 30 candidates for multi-bracket treatment were selected on the basis of certain exclusion criteria. The patients were divided into 4 groups: group 1: titanium brackets and fluorine protection; group 2: titanium brackets without fluorine protection; group 3: stainless-steel brackets and fluorine protection; group 4: stainless-steel brackets without fluorine protection.

RESULTS

Analysis of the brackets removed after 4months in the mouth, using scanning electron microscopy (SEM) with phase contrast, revealed a difference in the surface topography of the metal brackets and the presence of chromium coating on the surface of the titanium appliances.

Therapeutic efficacy of self-ligating brackets: A systematic review

INTRODUCTION

Over the last few years, the use of self-ligating brackets in orthodontics has progressed considerably. These systems have been the subject of numerous studies with good levels of evidence making it possible to evaluate their efficacy and efficiency compared to conventional brackets. The aim of this study was to evaluate the therapeutic efficacy of self-ligating brackets by means of a systematic review of the scientific literature.

MATERIALS AND METHODS

A systematic study was undertaken in the form of a recent search of the electronic Pubmed database, oriented by the use of several keywords combined by Boolean operators relating to the therapeutic efficacy of self-ligating brackets through the study of tooth alignment, space closure, expansion, treatment duration and degree of discomfort. The search was limited to randomized controlled studies, and two independent readers identified studies corresponding to the selection criteria.

RESULTS AND DISCUSSION

The chosen articles comprised 20 randomized controlled trials. The studies analyzed revealed the absence of significant differences between the two types of system on the basis of the clinical criteria adopted, thereby refuting the hypothesis of the superiority of self-ligating brackets over conventional systems.

[How to treat hypoplasia of the lateral upper incisors by canine substitution : a clinical case]

INTRODUCTION

Facing a patient with a morphological or numerical disorder of the lateral upper incisors (mainly pegged or missing incisor), the orthodontist has to choose between two treatment options : either spatial planning for a prosthetic restoration, or space closure with substitution of the lateral incisors by canines; the choice depends on the clinical context we are faced with. Each treatment option has its advantages and disadvantages and it is hard to tip the balance in one direction or another.

MATERIAL AND METHOD

This article illustrates the rationale for therapeutic management of space closure, in a patient with skeletal class III, with hypoplastic and peg-shaped upper lateral incisors.

[Timing of alveolar bone graft and sequences of canine eruption in cases of cleft lip and palate: a systematic review]

INTRODUCTION

The alveolar bone graft (ABG) is an important phase in the surgical treatment of cleft lip and palate (CLP). The purpose of alveolar bone grafting is to eliminate oronasal fistulas, restore the continuity of the maxilla and provide optimal periodontal support for spontaneous eruption of permanent canines adjacent to the cleft. The purpose of this systematic review was to determine the ideal timing of the ABG that would achieve these goals.

MATERIAL AND METHODS

Databases consulted were MEDLINE, Embase et EBSCOhost, using keywords present in the MeSH: [cleft lip and palate] and [alveolar bone graft] and [tooth eruption]. Selection criteria included retrospective studies, prospective studies and meta-analyzes dating from January 2005, with available full text.

RESULTS

Among 105 references, 9 articles met our selection criteria. ABG carried out before or just after the eruption of permanent canines adjacent to the cleft, between 8 and 12 years old, has the best success rate of the transplant (71% to 89%) and the lowest risk of canine inclusion (5% to 19%).

CONCLUSION

According to literature data, the optimal timing of ABG that provide best results is located between 8 and 12 years, before or just after the eruption of permanent canines adjacent to the cleft. However, this timing could be modified by the multidisciplinary team according priorities, particularly aesthetic, defined for each child.

Residual craniofacial growth: A cephalometric study of 50 cases

Although orthodontists focus intensively on the diagnosis and treatment of their patients, they pay less attention to post-treatment development and the risk of relapse often caused by the late growth of the arches and bony base. The aim of this study, therefore, was to determine the growth changes, which can affect craniofacial dimensions in subjects aged between 13 and 17 years. A retrospective longitudinal study including 50 patients (31 girls and 19 boys) whose end of orthodontic treatment coincided with the end of the post-pubertal period (13-14 years) involved a comparison of the cephalometric analyses for each patient between T1 (end of orthodontic treatment) and T2 (end of retention). The study evidenced changes in the post-pubertal craniofacial dimensions in the vertical and sagittal dimensions. Girls and boys do not have the same potential for growth at the age of 13 years. The residual growth phenomenon is more present in boys than in girls with, on the one hand, an increase in the post-pubertal craniofacial dimensions affecting the mandible more particularly and, to a lesser degree, the maxillary sagittal dimension associated with a decrease in the vertical dimension.

A systematic study of the release of bisphenol A by orthodontic materials and its biological effects

INTRODUCTION

Bisphenol A (BPA) is a synthetic chemical substance used as a starting ingredient in the manufacturing process of a number or orthodontic materials. It is a well-known endocrine disruptor with low estrogenic properties. The aim of this investigation is to present a systematic review regarding the issue of bisphenol A release by orthodontic materials and its impact in orthodontics.

MATERIALS AND METHODS

A systematic analysis was performed by electronic search (between 1936 and 2015) on several data bases. The search was limited by using several specific key-words in two languages, English and French. Two investigators selected the responses, which met the selection criteria.

RESULTS AND DISCUSSION

Of the 376 studies found, only 21 met our selection criteria: 11 of these dealt with the release of bisphenol by orthodontic materials and 10 in vitro studies described the effects of BPA leaching from orthodontic materials on human and murine cells. The rate of BPA release was well below the daily tolerable intake (DTI) (50mg/kg/day in 2006, then 50μg/kg/day in 2015) according to the European Food Safety Authority (EFSA). Theoretical exposure to BPA was 11,000 times lower than recommendations. However, other studies have shown the presence of BPA and of monomers released in large quantities at very low doses. The effects of observed BPA varied significantly (toxic and carcinogenic potential) while some studies found no effects at all. The relatively small number of studies dealing with the release of Bisphenol A by orthodontic materials, apart from orthodontic materials and their significant biological effects, has led to the absence of standard protocols and has hindered precise determination of released BPA. Moreover, the lack of coherence between the various methodological approaches and variations in the experimental protocols have resulted in a low level of proof regarding the impact of BPA by orthodontic materials.

RECOMMENDATIONS

Through this study, the authors encourage clinicians to observe the following recommendations designed to reduce the amount of BPA released by materials used in orthodontics: keep the tip of the light-curing lamp as close as possible to the composite and perform indirect rather than direct light-curing; Pumice-polish the composite after bonding so as to reduce the potential amount of BPA released; reduce exposure by brushing or rinsing with a mouthwash during the first hour after bonding; follow a standardized, reproducible and expert-validated research protocol aimed at better understanding of BPA release.

Resorption of maxillary incisors after orthodontic treatment--clinical study of risk factors

INTRODUCTION

External apical root resorption (EARR) is one of the major problems associated with orthodontic treatment. Such lesions represent an iatrogenic risk that must be detected as early as possible, with regular radiological follow-up and appropriate therapeutic precautions. The causes and mechanisms leading to susceptibility to root resorption following the application of an orthodontic force are often not clear and are generally said to be of multifactorial origin. The aim of this clinical study was to analyze the factors linked to the occurrence of moderate to severe resorption (MSR) of upper incisors during orthodontic treatment in a group of Moroccan patients treated in the Dento-Facial Orthopedic Department of the Dental Consultation and Treatment Center (Centre de consultation et de traitements dentaires [CCTD]) in Rabat.

MATERIAL AND METHODS

A total of 82 patients (28% males, 72% females) aged between 12 and 27, with various malocclusions, who had been treated with fixed appliances for at least 1 year and for whom panoramic X-rays at the start, during and at the end of treatment were available, were selected randomly. The reduction in maxillary incisor root length was evaluated using resorption scores. The factors studied in relation to the risk of occurrence of MSR were: age, sex, treatment duration, extraction or non-extraction, type of malocclusion (Class I arch-length discrepancy, Class II, Class III), the vertical diagnosis (normal, supraocclusion, open bite), presence of dysfunction, impacted canines and root morphology. Statistical analysis was performed using SPSS software, version 18.0. Statistical tests used were: Kaplan-Meier analysis and the univariate and multivariate Cox models for the study of factors associated with MSR. The threshold of significance adopted was 0.05.

RESULTS

The factors that were significantly associated with the occurrence of MSR at the level of the upper incisors were: tooth type, with a greater risk for the lateral incisor (HR=3.2 95% CI [2.3-4.5] P<0.001), treatments with extraction (HR=1.64 95% CI [1.16-2.33] P<0.05), the presence of supraocclusion (HR=2.17 95% CI [1.33-3.53] P<0.05) or open bite (HR=3.12 95% CI [1.66-5.86] P<0.001) and root malformation (HR=1.5 95% CI [1.09-2.07] P<0.05). Age, sex, type of malocclusion, dysfunction and impaction of canines were not associated at a statistically significant level with the risk of occurrence of MSR of the upper incisors.

CONCLUSION

EARR is difficult to avoid; the orthodontist's role remains crucial in identifying risk factors so as to adopt a treatment strategy taking these factors into account. In our population, the risk of MSR in the upper incisors appeared to increase in treatments with extraction, situations of supraocclusion or open bite, and in the presence of root abnormalities. Finally, clinical recommendations for the prevention of the occurrence of MSR of the maxillary incisors are proposed, taking into account all the risk factors identified.

[Orthodontic correction of a Brodie syndrome case related to oral habits]

Unilateral Brodie bite, called also Scissor bite, is a form of transversal malocclusion that often leads to minor facial asymmetry. The prevalence of this form of malocclusion is rare, especially met in mixed denture. We report a case of 11-year-old girl who presents unilateral scissor bite related to oral habits, with a skeletal class II. Modified activation by contraction of a bi-helix appliance was used to treat the unilateral scissor bite occlusion, before approaching the correction of the sagittal relationship.

Significant correlation between salivary and serum Ca 15-3 in healthy women and breast cancer patients

The tumor marker CA 15-3 is one of the most import reliable for metastatic breast cancer monitoring. While it is generally assessed in serum of patients, blood sampling is an invasive method compared to saliva sampling which is simple and could be an alternative to blood according to many studies. The aim of this investigation was to assess the relationship between serum and salivary concentrations of the protein CA 15-3 in patients with breast cancer and healthy asymptomatic volunteers. A case-control study was conducted with 60 women: 29 breast cancer patients from the Maternity Hospital Souissi Rabat (Morocco) and 31 healthy asymptomatic women. The CA 15-3 concentrations in saliva and serum samples were assessed using an enzyme immune assay (EIA kits) and comparison between cases and controls was made by the Mann-Whitney test. The correlation between serum and saliva CA 15-3 concentration was tested using Pearson correlation. The comparison result of CA15-3 concentration in saliva and serum level in cases and controls was not statistically significant (p>0.05). However, the correlation between salivary and serum CA 15-3 concentration was positive and statistically significant (r=0.27, p=0.03). In conclusion, the positive correlation between salivary and serum expression found in our study suggests that saliva could be an alternative to blood sampling to help breast cancer monitoring.

Cytotoxicity of elastomeric power chains in artificial saliva: an in vitro study

INTRODUCTION

The main aim of this paper is to investigate the cytotoxicity of elastomeric power chains after stretching and immersion in a solution of artificial saliva.

MATERIALS AND METHOD

Two brands of grey polyurethane power chains available from two different firms (GAC, G&H) were selected for cytotoxicity assay. Each segment was stretched up to an initial force of approximately 200 g. Then each segment was kept stretched using appropriate equipment. The samples were tested in artificial saliva at two pH levels, pH7 and pH4. Following incubation, the saliva was removed, filtered and placed in contact with cell culture media using the RD line.

RESULTS AND DISCUSSION

At this supernatant dilution, no statistically significant difference was observed between the different groups of power chains studied in terms of cell viability. The GAC and G&H power chains, whether stretched or not and immerged in either pH7 or pH4 saliva, showed no toxic effect on RD cells (human cell line).

[Contribution of the cervical vertebral maturation (CVM) method to dentofacial orthopedics: update]

The successful orthopedic treatment of skeletal Class II malocclusions is closely related to the reasoned determination of the optimal time to initiate the treatment. This is why various methods have been proposed to assess skeletal maturation, such as a hand-wrist radiograph or the cervical vertebral maturation (CVM) method. The hand-wrist radiograph was up to now the most frequently used method to assess skeletal maturation. However, the clinical and biological limitations of this technique, as well as the need to perform an additional radiograph, were reasons to develop another method to explore the maturation stages of visible cervical vertebrae on a simple lateral cephalometric radiograph. The authors compare the 2 methods and prove the greater contribution of the CVM method compared to the hand-wrist radiograph.

The single nucleotide polymorphism +936 C/T VEGF is associated with human epidermal growth factor receptor 2 expression in Moroccan breast cancer women

The vascular endothelial growth factor (VEGF), a potent regulator of angiogenesis, is involved in the development and progression of breast cancer (BC). The functional +936 C/T polymorphism of the VEGF-A gene has been implicated in BC susceptibility; however, published data are conflicting. In the current case-control study, we analyzed the association of the +936 C/T polymorphism with BC risk and tumor markers expression, human epidermal growth factor receptor 2 (HER2/neu) and caner antigen 15.3 (CA 15.3) in Moroccan women. We genotyped the DNA of 70 BC patients and 70 healthy women by TaqMan SNP assays. The χ(2) test and Fisher's exact test were used for statistical analyses. The overall results revealed that there is no association between the +936 C/T polymorphism and BC risk [p = 0.8; OR 0.87, 95 % CI (0.32-2.42)]. However, when we stratified the group of patients according to the status of tumor markers, a statistical significant association of +936 C/T SNP and HER2/neu expression was observed (p = 0.009). In contrast, no association with the other tumor marker, CA 15.3, was found (p = 0.090). Thus, the +936 C/T polymorphism seems to have a correlation with HER/neu expression in BC disease.

Degradation of the mechanical properties of orthodontic NiTi alloys in the oral environment: an in vitro study

Appropriate characterization studies are needed to demonstrate the mechanical and biological effects of interaction between archwires and the oral environment. The aim of this study was to investigate, in vitro, the impact of this acidic and fluoridated environment on the electrochemical behavior and the mechanical properties of orthodontic alloys in nickel titanium and in stainless steel (controls) for the following parameters: Young's modulus (E), elastic limit (σe) and the maximum tensile load (σm). Six samples of each archwire alloy were used to assess these parameters. An Instron universal test apparatus (model - 88512) was used for the traction tests on the wires after immersion in solutions at different concentrations of fluoride and at various pH levels. Observations were made using an electron scanning microscope (ESM) to evaluate the surface and an ICP (inductively coupled plasma) mass spectroscopy analysis was made to quantify the substances released into the immersion solution. For the NiTi archwires, immersion in the fluoridated and acidic medium showed a statistically significant reduction of the Young's modulus (E), the elastic limit (σe) and the maximum tensile load (σm). Similarly, a higher level of released nickel proportionate to the increase in the fluoride concentration and acidity was observed in the immersion solutions. ESM observations revealed the status of the surface of the different alloys and the presence of corrosive pitting.

[Prevalence and clinical characteristics of oral bony outgrowth in a Moroccan population]

OBJECTIVES

Oral bony outgrowths (OBOs) are localized bony protuberances that arise from the cortical plate. Various types of OBOs have been described, the precise designation of which depends on anatomic location such as torus palatinus, torus mandibularis, buccal exostosis, or palatal exostosis. We had for aim to determine the prevalence and clinical characteristics of OBOs in a Moroccan population.

METHODS

This cross-sectional study was conducted between March 15 and June 30, 2011 at the Rabat-Salé teaching hospital dental consultation and treatment center, in Morocco. Three hundred and fifty-three patients (160 female and 193 male patients), 11 to 82 years of age, were examined clinically and radiologically to determine the presence of OBO.

RESULTS

Twenty-four patients (6.8%) presented with OBOs. The prevalence for exostosis, torus mandibularis, torus palatinus, and associated OBOs was 3.1%, 2%, 0.8%, and 0.9% respectively. There was a significant difference (P=0,01) between the average age for patients presenting with OBO (43.2±12 years of age) and the average age for patients without any OBO (36.5±16 years of age). The prevalence of OBOs in female patients (7.3%) was higher than in male patients (6.3%) but the difference was not significant (P=0.439). Patients with occlusal parafunctional activity presented with significantly more OBO (P=0.016).

DISCUSSION

The reported prevalence of OBO is extremely variable, according to age, gender, and ethnic group. The occurrence of OBO could be triggered by genetic factors associated with environmental factors.

Salivary expression of soluble HER2 in breast cancer patients with positive and negative HER2 status

Background

The aim of this study was to investigate the relationship between salivary concentration of the soluble fragment of the HER2 (human epidermal growth factor receptor) protein and its status in mammary tissues.

Methods

This case-control study was done in 27 breast cancer patients with no visible metastatic disease treated at the gynecology service, Maternity Souissi Hospital, Rabat, Morocco. Two groups were selected, ie, patients with positive and negative HER2 status in mammary tissue. The salivary HER2 protein concentration was assessed by enzyme-linked immunosorbent assay. The salivary HER2 concentration was compared between the HER2-positive and HER2-negative groups using the Mann-Whitney U test. A P-value <0.05 was considered to be statistically significant.

Results

No statistically significant difference in salivary HER2 protein expression was found between the case and control groups. There was also no significant difference in clinical characteristics according to positive and negative HER2 status (P>0.05), except for the progesterone hormone receptor which was statistically significant in both the case and control groups (P=0.047).

Conclusion

According to our data, salivary expression of the HER2 receptor may not be a reliable alternative to tissue assessment.

Study of variations of the Bolton index in the Moroccan population depending on angle malocclusion class

Many difficulties may arise during the finishing phase of orthodontic treatment on account of discrepancy between mandibular and maxillary tooth size. In 1958, Bolton devised the index that bears his name and enables possible tooth-size discrepancy to be diagnosed. Use of this index in practice has shown that it can vary depending on the different angle malocclusion classes. The aim of this work is to study variations of the Bolton index as a function of the malocclusion class in the Moroccan population, and to compare the results obtained with those of other populations. Ninety models were therefore selected in different groups of dental Class I, Class II and Class III malocclusions. The mesiodistal (MD) diameters of 12 maxillary and mandibular teeth were measured and the anterior and general Bolton indices were calculated. The results obtained show that there is no significant difference between the various groups of angle malocclusion classes, and that some other populations present results similar to those of the Moroccan sample.