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.

Venous resection for pancreatic cancer, a safe and feasible option? A systematic review and meta-analysis

BACKGROUND

In pancreatic ductal adenocarcinoma patients with suspected venous infiltration, a R0 resection is most of the time not possible without venous resection (VR). To investigate this special kind of patients, this meta-analysis was conducted to compare mortality, morbidity and long-term survival of pancreatic resections with (VR+) and without venous resection (VR-).

METHODS

A systematic search was performed in Embase, Pubmed and Web of Science. Studies which compared over twenty patients with VR + to VR-for PDAC with ≥1 year follow up were included. Articles including arterial resections were excluded. Statistical analysis was performed with the random effect Mantel-Haenszel test and inversed variance method. Individual patient data was compared with the log-rank test.

RESULTS

Following a review of 6403 papers by title and abstract and 166 by full text, a meta-analysis was conducted of 32 studies describing 2216 VR+ and 5380 VR-. There was significantly more post-pancreatectomy hemorrhage (6.5% vs. 5.6%), R1 resections (36.7% vs. 28.6%), N1 resections (70.3% vs. 66.8%) and tumors were significantly larger (34.6 mm vs. 32.8 mm) in patients with VR+. Of all VR + patients, 64.6% had true pathological venous infiltration. The 90-day mortality, individual patient data for overall survival and pooled multivariate hazard ratio for overall survival were similar.

CONCLUSION

VR is a safe and feasible option in patients with pancreatic cancer and suspicion of venous involvement, since VR during pancreatic surgery has comparable overall survival and complication rates.

In the Era of the Leeds Protocol: A Systematic Review and A Meta-Analysis on the Effect of Resection Margins on Survival Among Pancreatic Ductal Adenocarcinoma Patients

BACKGROUND AND AIMS

A positive resection margin is considered to be a factor associated with poor prognosis after pancreatic ductal adenocarcinoma resection. However, analysis of the resection margin is dependent on the pathological slicing technique. The aim of this systematic review and meta-analysis was to study the impact of resection margin on the survival of pancreatic ductal adenocarcinoma patients whose specimens were analyzed using the axial slicing technique.

MATERIAL AND METHODS

A systematic search in the PubMed, Cochrane, and Embase datasets covering the time period from November 2006 to January 2019 was performed. Only studies with axial slicing technique (Leeds Pathology Protocol or Royal College of Pathology Protocol) were included in the final database. Meta-analysis between the marginal distance and survival was performed with the Inverse Variance Method in RevMan.

RESULTS

The systematic search resulted in nine studies meeting the inclusion criteria. The median survival for a resection margin 0 mm ranged from 12.3 to 23.4 months, for resection margin <0.5 mm 16 months, for resection margin <1 mm ranged from 11 to 27.5 months, for resection margin <1.5 mm ranged from 16.9 to 21.2 months, and for resection margin >2 mm ranged from 53.9 to 63.1 months. Five studies were eligible for meta-analysis. The pooled multivariable hazard ratio favored resection margin ⩾1 mm (hazard ratio: 1.32 and 95% confidence interval: 1.03-1.68, p = 0.03).

CONCLUSION

Resection margins ⩾1 mm seem to lead to better survival in pancreatic ductal adenocarcinoma patients than resection margin <1 mm. However, there is not enough data to evaluate the effect of oncologic therapy or to analyze the impact of other resection margin distances on survival.

Gemcitabine-based adjuvant chemotherapy in subtypes of ampullary adenocarcinoma: international propensity score-matched cohort study

BACKGROUND

Whether patients who undergo resection of ampullary adenocarcinoma have a survival benefit from adjuvant chemotherapy is currently unknown. The aim of this study was to compare survival between patients with and without adjuvant chemotherapy after resection of ampullary adenocarcinoma in a propensity score-matched analysis.

METHODS

An international multicentre cohort study was conducted, including patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma between 2006 and 2017, in 13 centres in six countries. Propensity scores were used to match patients who received adjuvant chemotherapy with those who did not, in the entire cohort and in two subgroups (pancreatobiliary/mixed and intestinal subtypes). Survival was assessed using the Kaplan-Meier method and Cox regression analyses.

RESULTS

Overall, 1163 patients underwent pancreatoduodenectomy for ampullary adenocarcinoma. After excluding 187 patients, median survival in the remaining 976 patients was 67 (95 per cent c.i. 56 to 78) months. A total of 520 patients (53·3 per cent) received adjuvant chemotherapy. In a propensity score-matched cohort (194 patients in each group), survival was better among patients who received adjuvant chemotherapy than in those who did not (median survival not reached versus 60 months respectively; P = 0·051). A survival benefit was seen in patients with the pancreatobiliary/mixed subtype; median survival was not reached in patients receiving adjuvant chemotherapy and 32 months in the group without chemotherapy (P = 0·020). Patients with the intestinal subtype did not show any survival benefit from adjuvant chemotherapy.

CONCLUSION

Patients with resected ampullary adenocarcinoma may benefit from gemcitabine-based adjuvant chemotherapy, but this effect may be reserved for those with the pancreatobiliary and/or mixed subtype.

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.

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.

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.

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.

Percutaneous treatment of extrahepatic recurrence of hepatocellular carcinoma

PURPOSE

The goal of this study was to retrospectively evaluate the results of imaging-guided percutaneous ablation in patients with controlled intrahepatic hepatocellular carcinoma (HCC) with limited extrahepatic disease.

MATERIALS AND METHODS

Eleven patients with limited extrahepatic disease and/or potential short-term clinical manifestations with controlled primary intrahepatic HCC were included into the study. There were nine men and two women, with a mean age of 67.4 years±10.2 (SD) (range: 54-85 years). All patients had extrahepatic disease treated by either radiofrequency ablation or electroporation. Extrahepatic disease consisted of lymph node metastases (5 patients), tumor seeding along a needle tract (3 patients), adrenal gland metastasis, bone metastasis and pulmonary metastasis (one patient each).

RESULTS

Response to treatment was complete in 7/11 patients (64%). The mean survival time after treatment was 18.8±12.7 (SD) months (median, 16 months; range: 4-42 months). No severe complications associated with percutaneous treatment were observed.

CONCLUSION

Our results suggest that imaging-guided percutaneous ablation techniques should be considered as a useful option for the treatment of extrahepatic disease in patients with HCC. Further studies are needed, however to fully determine the potential role of these techniques in this elective application.

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).

Surgical-orthodontic treatment of patients suffering from severe periodontal disorders - a clinical case study

INTRODUCTION

Orthodontic or, more precisely, surgico-orthodontic treatment of patients suffering from periodontal disorders generally requires a multidisciplinary approach by a qualified dental team. Periodontal bone healing is an essential factor for successful orthodontic treatment in a compromised periodontal situation.

CLINICAL CASE

We report on the case of an adult patient suffering from severe chronic periodontitis; he was a hyperdivergent skeletal Class III with dento-alveolar compensation, esthetic problems and a significant lack of dental material. A multidisciplinary approach was adopted. First of all, periodontal treatment was undertaken (root scaling and planing) accompanied by appropriate medical treatment and a bone graft to strengthen the area of the lower incisors. After that, surgical and orthodontic treatment to correct the malocclusion was begun. The difficulty lay in the significant absence of dental material to ensure proper intercuspation. A surgical repositioning splint was constructed on an articulator to ensure adequate mandibular retraction after maxillary advancement surgery. After treatment, the missing teeth were replaced by a prosthesis.

RESULTS AND DISCUSSION

Following treatment, the periodontal bone resorption was stabilized; the bone deficit was improved and the malocclusion had been corrected; the missing teeth were replaced by appropriate dentures. Short- and medium-term follow-up confirmed the stability of the results obtained, which will be discussed.

CONCLUSION

The right combination of properly managed orthodontic, periodontal and prosthetic treatment can contribute to effective elimination of chronic periodontitis, even at an advanced stage in an adult patient, while at the same time improving esthetic and functional parameters.

Elastomeric chain force decay in artificial saliva: an in vitro study

INTRODUCTION

The main objective of this study was to reexamine the mechanical properties of elastomeric chains after stretching in various artificial saliva solutions and in air.

MATERIALS AND METHODS

Five brands of elastomeric chain manufactured by different companies were selected. For each brand, four types were tested in different artificial media. A dismountable test kit was used to stretch the chains up to various initial force levels. They were then immersed in pre-prepared solutions, with control samples exposed to air only. Residual force was measured at multiple time points using a hand-held dynamometer.

RESULTS AND DISCUSSION

The force delivered by the elastomeric chains decayed rapidly and differently over time. This decay varied depending on multiple factors, discussed here.

A systematic review of force decay in orthodontic elastomeric power chains

INTRODUCTION

Elastomeric chains are one of several devices used to provide force for orthodontic tooth movement, but the force they exert diminishes over time and can thus be difficult to control. The objective of this investigation was to provide a systematic review of publications pertinent to force decay in orthodontic elastomeric chains.

MATERIALS AND METHODS

A systematic review was performed via electronic querying of multiple databases for the period 1970-2011. Queries were limited to a set of specific keywords in two languages (English and French). Five main reviews were consulted manually to identify relevant publications. Two investigators sorted out those studies that complied with selection criteria.

RESULTS AND DISCUSSION

A total of 53 studies were found to be relevant to force decay in elastomeric chains, including 22 on force decay over time, seven on the force consequences of pre-stretching, 12 on the impact of the environment on the force delivered, and 11 on clinical efficacy.

CONCLUSION

The force delivered by elastomeric chains decays rapidly over time, affecting their mechanical properties and clinical efficacy when studied in either human saliva or laboratory test media.

[Comparative study of measurement of posterior tooth crowding between the dental panoramic xray and dental scanner]

The purpose of this work was to compare measurements of the posterior crowding in the mandibular arcade between two types of radiographic examinations: the dental panoramic one and the dental scanner. Our sample is composed of 12 patients before treatment orthodontic, with an average age of 16 + 4 years. These patients presented an posterior crowding on dental panoramic radiography accepted the catch of a dental scanner to re-examine this crowding. To make this study, we measured on dental panoramic radiographies and the dental scanners of each patient posterior available space and posterior necessary space according to the technique of Merrifield and we calculated the posterior crowding for each case. The comparison of the two variables was carried out by using the Test T of Student. The results our study shows that: Dental panoramic radiography raises the posterior dental crowding when this compared to the dental scanner (Student, p < 0.05). The percentage of enlarging of this crowding varies enormously between 18 % and 73% with an average of 48.58 % +/- 15, 90.

[A comparative study of the transverse dimensions of the dental arches between Class I dental occlusion and Class II1 and Class II2 malocclusions]

The purpose of this work was to compare transverse dimensions of the maxillary and mandibular arches in the canine and molar region between three groups of patients: the first group had an occlusion in class II division 1, the second one a dental class II division 2 and the third one, a class I bite. Our sample is composed of 94 patients, with an average age of 20 +/- 3 years: 31 patients presented a class I occlusion, 33 a class III1 and 30 cases presented a dental class II2. For this study, we measured, on the maxillary and mandibular dental casts of each patient, the intercanine and intermolar canine (central inter fossa). Comparison of variables was conducted using the variance analysis ANOVA; the selected post-hoc test is the Bonferrroni test. On the basis of our study, we can get the following results: Maxillary intercanine distance is narrower in class II1 compared to class II2 of 2 mm "p < 0.05". Mandibular intercanine distance is narrower in class III1 compared to class II2 of 1, 3 mm "p < 0.05". Maxillary intermolar distance (inter fossa) is narrower in class II1 compared to class I of 2, 2 mm "p < 0.05".

[Open bite and and therapeutic strategy]

Anterior open bites can be divided into two categories: skeletal and dento-alveolar. The etiology, basically affecting dento-alveolar structures, is functional or mechanical such as the rotation of the first higher molars, the exaggerated curve of Spee and the incisor supraclusion and the simple orthodontic treatment can bring a therapeutic success but functional rehabilitation remains the guaranty of such a stability of our treatment. The purpose of this work is to make a teaching article which puts the point on the interest of the elements of the diagnosis and the orthodontic treatment indicated in certain clinical situations of anterior open-bite; this by detailing biomechanics of correction of this anomaly requiring various therapeutic strategies. Functional rehabilitation remains always the guaranty of such a therapeutic stability. For the teaching aspect, we want to attach stereotypic forms and also to present clinical cases treated in the service of consultation and dental treatment in order to answer such a request.

[Influence of premolar extraction on the dimensions of the lower dental arch: clinical study of 30 cases]

The purpose of this work is to study the form's and transversal dimensions changes of dental arches during the orthodontical treatment within the first premolars extractions. Our sample is composed of thirty treated casts in Edgewise technique in the orthodontic service in Center of Consultation and Dental Treatment (C.C.D.T.) of Rabat. In order to realise this study, we have used in the treatment's beginning and final of each case mandibular moulding. On our results base, it brings out that the intercanine distance increases whereas the intermolar distance decrease during the orthodontical treatment, and that the only found dismorphism is linked to the treatment's options (extraction- non extraction) only for intermolar distance.

[What measures can be taken to reduce the number of smoking adolescents and young women?]

A proper understanding of the factors exposing adolescents and young women to the risk of smoking dependence is necessary to develop effective preventive measures. These measures will be different depending on whether they are designed for adolescents and young women in general or for the context of pregnancy. For adolescents, efforts should be continued to provide information about smoking and the dangers of tobacco as well as about the social manipulation involved. The image of a natural, active woman, free of tobacco and capable of making her own decisions should be promoted. Health education and communication professionals should make use of different media with an audience among the young. Messages should be validated with a target population before diffusion. A better coherence between the adult and young populations concerning legal obligations and mutual respect is significantly useful. Educational structures (schools and universities) should participate in long-term community projects implicating peer groups and trained professionals. Values which should be reinforced include self-esteem, affirmation of personal competence and difference, self-respect and respect of others. Early identification of factors favoring psychosocial vulnerability at this age is indispensable to facilitate referral to professional support and care centers, the number of which remains insufficient to date. Support when ceasing smoking, based on individual and group assistance, should take into account the individual's phase of maturation, and must be proposed and operated by trained professionals working in a network. During pregnancy, it is crucial to recognize that the woman's specific physical and psychological situation is a unique opportunity to propose a new approach to smoking, taking into consideration the fragile context during this period of maturation and its impact on the woman's general life. Beyond sociopolitical measures and a philosophical debate on the position of women, men, and the family in the 21st century, propositions can be put forward for actions before, during and after the maternity period. It is important to continue the educational aspect without creating a guilt feeling. Messages should be elaborated with women. Healthcare professionals should be trained about smoking and smoking dependence. They should repeat minimal advice and continuously propose stopping smoking, taking into consideration the woman's stage of maturation and her motivation. Carbon monoxide monitoring should become a routine practice. Prognostic factors and possible difficulties should be identified early, if possible before pregnancy or at least during pregnancy, in order to propose adapted multidisciplinary support. The health booklet for the mother and the infant should be improved. Midwives should play an important role in prevention. A multidisciplinary effort will have the greatest impact: smoke-free environment in maternities, professional clinics, and the real-life territory of the pregnant woman. Individual care and support are more appropriate than group support. The partner should be implicated. For very dependent women, basically psychological support of smoking cessation should be completed with nicotine substitution therapy using protocols which should be redefined with more extensive studies. All these measures should be continued for six months after birth whether the woman has stopped smoking during pregnancy or not.