Evaluation of Electric Scooter Head and Neck Injuries in Paris, 2017-2019

This case series study evaluates head and neck injuries caused by electric scooters in Paris, 2017-2019, focusing on user behavior and injury types.

Knowledge and perception of the French ANSM recommendations for acute odontogenic cellulitis in French private dental practices: a national survey

Introduction: Caring for acute odontogenic cellulitis involves drainage, treatment of the tooth and the administration of antibiotic therapy (ANSM 2011). The emergence of bacterial resistance mechanisms has led to formulating actions to promote better use of antibiotics, but France stay one of the largest consumers in Europe. Objectives: Evaluate the impact of ANSM's recommendations on dental surgeons in France for treatment of this affection. Methods: We performed a national survey with 12365 practitioners who received the questionnaire by email. Results: On 690 responder practitioners, 13% followed the recommendations to the letter and 70.5% performed a clinical intervention on the day of emergency. Only 1/3 of cases involved the prescription of amoxicillin alone for first line treatment. Conclusion: Few data exist on the evaluation of the impact of recommendations regarding this subject, but it is generally accepted it they are seldom followed. The reasons expressed are many: disagreement between practitioners on the efficiency of recommendations, lack of time and organizational constraints.

Antibiotic use and resistance: a nationwide questionnaire survey among French dentists

The aim of this survey was to describe the attitudes and self-reported practices of French dentists towards antibiotic use and resistance and to compare practices with national guidelines. A nationwide cross-sectional internet-based survey was conducted among the 41,800 French dentists. The online questionnaire was distributed through professional networks from April 2017 to April 2018. Seven-hundred seventy-five dentists participated but only 455 questionnaires were complete enough to be included in the analyses. Amoxicillin was the most frequently prescribed antibiotic (65.8%, 1783/2711), followed by spiramycin + metronidazole fixed-dose combination (11.6%, 312/2711) and amoxicillin-clavulanic acid (10.3%, 279/2711). The main indications for use were abscess (349/423, 82.5%), cervicofacial cellulitis (74.2%, 314/423), and pericoronitis (58.6%, 239/408). Most dentists (90.5%, 381/421) considered that antibiotic resistance is of concern but only half of them (56.3%, 238/423) felt adequately informed about antibiotic use. Many dentists did not comply with the national guidelines: the majority of them declared inappropriate antibiotic prescriptions for 11/17 clinical situations. They did not prescribe antibiotics for 5/6 clinical situations requiring prophylaxis. They reported that the publication of clinical guidelines is the main factor influencing their prescriptions (71.0%, 299/421). They wished to receive regular updates of national guidelines in the form of practical sheets (93.0%, 172/185). French dentists should urgently be targeted by antibiotic stewardship initiatives.

A non-syndromic case of maxillo-mandibular keratocysts

Introduction: Odontogenic keratocysts (OKCs) are frequent, aggressive lesions with a strong tendency to recur, particularly in their para-keratinized majority form. Although they are mainly non-syndromic, these lesions are found in a large majority of patients with Gorlin syndrome. Thus, multiple forms are almost always associated with this syndrome and require investigation to prevent the risk of various cancers. Non-syndromic multiple forms are exceptional. Observation: A 20-year-old patient presented with dual localization of maxillary and left mandibular OKC at consultation. Under general anesthesia, excision of the lesions and extraction of the impacted wisdom teeth 28 and 38 were performed. The patient showed no clinical sign of Gorlin syndrome. Discussion: The OKC or epidermoid cyst is derived from the dental lamina or its remnants and from the basal part of the oral epithelium and represents between 10 and 20% of all cystic lesions in the maxillae. Its peak of incidence is between the second and fourth decade (or earlier in case of association with basal cell necrosis). OKC occurs mainly in the mandible and preferentially at the Ramus, where its frequency can reach 70% depending on the series. Conclusion: The management of OKC by oral surgeons must be conducted in a multidisciplinary setting in close collaboration with dermatologists, geneticists, and anatomic pathologists. Due to the strong recidivating character of OKCs, patient monitoring is essential.

[Children's consultations for dental emergency. Retrospective study in Île-de-France]

BACKGROUND

In France, the children oral health status has improved but the use of care remains insufficient. The complexity of the acts, the access to care difficulties and the programs of prevention and care for children lack of knowledge contribute to late care and often, in emergency. This study aims to describe the young patients' characteristics consulting in dental emergency and analyse the modalities of recourse.

METHODS

A retrospective study was conducted on medical records. An extraction of data was carried out concerning all children under the age of 16, admitted to the Dental Emergency Functional Unit of the Pitié-Salpêtrière Hospital Group in 2015. Several variables of interest were analysed: socio-demographic characteristics, the time of the visit and the diagnostic category (tooth pathologies, facial trauma, infections, periodontal diseases and other emergencies). Descriptive and bivariate analyses were conducted.

RESULTS

On the 62,500 dental emergency consultations in 2015, 5359 were for patients under 16 years of age (8%). Data were available for 5044 children. Among these, children aged 6 to 11 accounted most of consultations (43.9%). There were more boys (57.2%). The most frequent emergency diagnoses were related to a tooth pathology (42.9%) and traumatic event (38.4%). Consultations were more held on the evening schedule on weekdays and the day on weekends. Patients aged 0 to 5 years consulted more at night (P<10^-3) and were, proportionally, the most affected by traumatic events (39.2%). Children aged 6 to 11 and 12 to 16 years consulted more often during the day (P<10^-3), for emergencies related to a carious event (43.9% and 43.6%). Patients residing in Seine-Saint-Denis accounted for 22.6% of total visits and those living in Paris accounted for 20.8%.

CONCLUSION

A large proportion of children presenting for dental emergencies, have most of the time, only the need for usual care. An offer of dental care, adapted to the territory needs, is necessary for the children dental health management. Preventive measures from an early age and early recourse would be favourable.

Palatal torus: etiology, clinical aspect, and therapeutic strategy

Introduction: Maxillary palatal tori are benign bone tumors that elevate the median of the palate. Although there are clinical variations, palatal tori are characterized by pathognomonic clinical and radiographic criteria. Observations: Here, we present the cases of two patients with a voluminous palatal torus that caused functional problems in one and formed an anatomical obstacle to the fitting of a removable prosthetic in the other. Given their size, these tori were surgically removed under general anesthesia. The postoperative course was simple. Discussion: The etiology of palatal torus is usually multifactorial: genetic factors, masticatory forces, and para-functions could all be factors in their development and growth. Considered as anatomical variations, palatal tori are asymptomatic in most cases and require no intervention. Conclusion: Surgical management is sometimes necessary to restore physiological orofacial functions or to allow the fitting of a prosthetic without harmful compromise.

Perioperative management of oral anticoagulated patients undergoing an oral, implant, or periodontal procedure: a survey of practices of members of two dental scientific societies, the PRADICO study

OBJECTIVES

Studies on the perioperative management of patients on direct oral anticoagulants (DOACs) receiving oral invasive procedures are sparse. Moreover, the recommendations of the scientific societies on DOACs are discordant, and the practices are highly variable. We conducted a survey of general and specialized dentists in France to compare their practices concerning the management of patients receiving vitamin K antagonists (VKAs) and DOACs.

MATERIALS AND METHODS

Members of two dental surgical societies were invited to participate in the survey. One hundred forty-one practitioners answered an online questionnaire focusing on the periprocedural management of oral anticoagulated patients (participation rate, 17.8%).

RESULTS

Practitioners at hospitals or mixed practices and specialists treated significantly more anticoagulated patients and more frequently performed procedures with high hemorrhagic risk than practitioners with private practice and general dentists. Greater than 90% of practitioners did not modify the treatment for patients on VKAs and controlled the International Normalized Ratio (INR) preoperatively. Regarding DOACs, 62.9% of practitioners did not change the treatment, 70.8% did not prescribe any biological tests, and 13.9% prescribed an INR. Practitioners at hospitals and mixed practices and specialists had better training and knowledge about DOACs.

CONCLUSIONS

This survey showed that anticoagulated patients were managed mostly by specialists in private or hospital care, notably when requiring oral procedures at high hemorrhagic risk.

CLINICAL RELEVANCE

A growing proportion of anticoagulated patients are being treated by dentists in primary care. Consequently, they need training, especially concerning DOACs. Additionally, consensus recommendations are necessary for better coordination of stakeholders and patient safety. Trial registration on ClinicalTrials.gov : NCT03150303.

Knowledge and practices of dentists in France regarding oral mucosal diseases: a national survey

Introduction:One of the dental surgeon's roles is to identify, diagnose and supervise the treatment of oral pathologies (OP), and/or to refer patients to the appropriate specialists. Today, the delay in diagnosing patients with OP is very long and may impact their prognosis.Objective:We conducted a national survey of French practitioners to estimate their knowledge and practices regarding the management of these pathologies.Methods:About 15,000 dentists were contacted by email to complete a questionnaire designed to assess the diagnoses and management of OP.Results:Overall, for 560 answers (3.8%), DS did not declare any significant difficulties in diagnosing and managing any kind of pathologies. However, we were able to distinguish statistical differences among practitioners depending on the type of lesions and between the practitioners themselves. The associated factors were gender, graduation year, mode of practice and continuing education over the last 5 years. The majority of DS justified their diagnostic difficulties by the fact that they do not encounter patients with these types of pathology frequently enough, and by insufficient education.Conclusion:According to our study, it is necessary to reinforce the training and the continuing medical education of DS regarding OP, especially through the use of practical cases.

Management of mTOR inhibitors oral mucositis: current state of knowledge

Introduction: Mucositis is a well-known side effect of classic anticancer treatments (chemotherapy and radiotherapy). Thanks to the major developments in personalizing treatments through the development of targeted treatment, various specific intraoral lesions have been described. Purpose: mTOR inhibitors are targeted anticancer treatments that are used to treat various cancer types. They can cause intraoral ulcerations that can be serious, and that can lead to a dose reduction or the anticancer treatment being stopped altogether. The management of these disabling and painful lesions is a major part of ensuring the efficiency of the cancer treatments. The objective of this article is to evaluate the current knowledge about the different treatments used nowadays, especially the preventive treatments. Conclusion: An efficient management of the lesions is a major part of the management of patients treated with mTOR inhibitors and should be carried out by the oral cavity specialists.

Molecular and cellular characterizations of human cherubism: disease aggressiveness depends on osteoclast differentiation

Background

Cherubism is a rare autosomal dominant disorder of the jaws caused by mutation of the SH3BP2 gene. The bone is replaced by a fibrous granuloma containing multinucleated giant cells. Cells of the cherubism granuloma have never been systematically analyzed. Hence, the aim of this study was to characterize the cells in human cherubism granulomas, to determine the osteoclastic characteristics of the multinucleated giant cells and to investigate the potential role of TNF-α in human cherubism.

Results

Seven granulomas were analyzed in pathology, molecular biology and immunohistochemistry. Granulomas were composed mainly of macrophages or osteoclasts within a fibroblastic tissue, with few lymphoid cells. Myeloid differentiation and nuclear NFATc1 localization were both associated with disease aggressiveness. OPG and RANKL immunohistochemical expression was unexpected in our specimens. Five granuloma cells were cultured in standard and osteoclastogenic media. In culture, cherubism cells were able to differentiate into active osteoclasts, in both osteoclastogenic and standard media. IL-6 was the major cytokine present in the culture supernatants.

Conclusion

Multinucleated giant cells from cherubism granulomas are CD68 positive cells, which differentiate into macrophages in non-aggressive cherubism and into osteoclasts in aggressive cherubism, stimulated by the NFATc1 pathway. This latter differentiation appears to involve a disturbed RANK-L/RANK/OPG pathway and be less TNF-α dependent than the cherubism mouse model.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0907-2) contains supplementary material, which is available to authorized users.

A questionnaire-based study evaluating differences between dental students in Paris (F) and Malmö (SE) regarding diagnosis and treatment decisions of patients with different severity levels of periodontal diseases

AIM

To evaluate differences between last-year dental students in Paris (F) and Malmö (SE) Dental Schools, in regard to their judgement and decision-making within periodontology.

MATERIALS AND METHODS

Ninety-six last-year dental students from Paris and 45 from Malmö participated in a questionnaire study based on four patient cases: (i) Patient case with generalised alveolar bone loss but no signs of inflammation (Well-maintained), (ii) Patient case with generalised alveolar bone loss and signs of inflammation (Periodontitis), (iii) Patient case with no alveolar bone loss and no signs of inflammation (Healthy) and (iv) Patient case with no alveolar bone loss but with signs of inflammation (Gingivitis). Through multiple-choice questions, the students judged each case as healthy or diseased proposed a diagnosis and treatment measures and estimated the treatment time for each patient. Furthermore, they assessed the prognosis of each patient in case of no treatment.

RESULTS

Based on a response rate of 83%, the majority in both groups judged all the patients as diseased. More Paris students diagnosed the healthy and the gingivitis case as having periodontitis (P < .05). Furthermore, a larger number of students from Paris recommended several treatment measures and estimated longer treatment times for all the cases (P < .05) and estimated a higher risk for disease progression for the healthy and the gingivitis case (P < .05).

CONCLUSIONS

Significant variation between students from Paris and Malmö Dental Schools in regard to judgement and decision-making was observed; this may in turn imply that there is still need of improving consistency amongst undergraduate educations in periodontology in Europe.

Neuropathic pain in the orofacial region: The role of pain history. A retrospective study

INTRODUCTION

Orofacial neuropathic pain is often difficult to treat, mostly because of still unclear underlying mechanisms. The occurrence of such neuropathic pain varies depending on different factors, of which preexisting preoperative pain seems to be of high importance. The aim of this study was thus to test the hypothesis that prior history of pain could indeed be considered a risk factor for the development of orofacial neuropathic pain in the same region.

METHODS

The study was performed in the dental department of the Groupe Hospitalier Pitié-Salpêtrière (GHPS) in Paris, France. We investigated the presence of prior inflammatory pain before development of orofacial neuropathic pain in 56 patients. For each patient file, the following items were collected: age, gender; medical history; diagnosis; description of the pain (at time of consultation); presence or absence of prior dental treatment; date and type of dental treatment received.

RESULTS

41 patients (73%) of orofacial neuropathic pain patients had a history of pain compatible with an inflammatory condition; 4% (n=2) did not report any prior pain and 23% (n=13) could not remember. Among the patients with documented history of pain prior to neuropathy, 88% (n=36) received surgical treatment; 61%, (n=25) endodontic treatment and 22%, (n=9) restorative treatment. All eventually received endodontic treatment or tooth extraction. These dental treatments are compatible with the hypothesis of prior inflammatory pain in these patients.

CONCLUSION

These results support the hypothesis that prior inflammatory pain could favor the development of orofacial neuropathic pain. Prevention and treatment of inflammatory trigeminal pain may therefore play a key role in preventing future neuropathic pain development.

Topical Review: Potential Use of Botulinum Toxin in the Management of Painful Posttraumatic Trigeminal Neuropathy

Painful posttraumatic trigeminal neuropathy (PPTTN) is a chronic condition that is difficult to endure and has a poorly understood pathophysiology. Treatment options are limited and often unsatisfactory due to insufficient efficacy and significant adverse effects. Botulinum toxin type A (BTX-A), initially used in the management of pathologically sustained or twisting muscular contractions, has recently been advocated for treatment of neuropathic pain. Its action is not limited to the blockage of acetylcholine release at the neuromuscular junction, but also includes inhibition of exocytosis of other neurotransmitters by interfering with the SNARE complexes of synaptic membranes. When injected into the painful location, the toxin can be taken up by peripheral terminals of nociceptive afferent nerve fibers, and this action suppresses peripheral and central release of algogenic neurotransmitters such as glutamate or substance P, thus promoting analgesia. Several randomized controlled trials in humans have provided emerging evidence for the therapeutic use of BTX-A in neuropathic pain states, including trigeminal neuralgia. This evidence, in addition to its good safety profile and long-lasting effect, suggests that BTX-A could be a potential novel treatment for PPTTN.

Opiorphin levels in fluids of burning mouth syndrome patients: a case-control study

OBJECTIVES

Idiopathic Burning mouth syndrome (iBMS) is a poorly understood affection characterized by persistent pain in the oral cavity without any clinical or biological abnormality. Opiorphin is a natural inhibitor of enkephalin-inactivating ectopeptidases, mainly produced by salivary glands, that has demonstrated analgesic properties. The objective of the present case-control study was to test the hypothesis of a decrease in opiorphin levels in iBMS patients.

MATERIALS AND METHODS

Twenty-one iBMS patients and 21 matched controls subjects were included between 2011 and 2013. Submandibular and sublingual salivary, blood, and urinary opiorphin levels of iBMS patients were compared to controls.

RESULTS

Results are expressed as mean values ± SD and compared using the Wilcoxon Signed Rank test. Correlations were analyzed with Spearman coefficient. The level of significance was fixed at p < 0.05. Opiorphin levels in iBMS and controls were respectively (in ng/ml) in basal saliva: 37.8 ± 42.5 and 67.6 ± 188.9 (p = NS); stimulated saliva: 28.8 ± 25.3 and 31.1 ± 29.1 (p = NS); blood: 4.6 ± 5.4 and 1.9 ± 1.4 (p < 0.05); and urines: 68.5 ± 259.8 and 8.9 ± 6.2 (p = NS).

CLINICAL RELEVANCE

In conclusion, the lack of significative difference in salivary opiorphin levels between iBMS and controls does not favor a direct local role for opiorphin in the etiopathogeny of iBMS. However, higher blood opiorphin levels may reflect a systemic dysregulation in iBMS. Trial registration NCT02686359 https://clinicaltrials.gov/ct2/show/NCT02686359.

Defining a new aggressiveness classification and using NFATc1 localization as a prognostic factor in cherubism

Cherubism is a rare genetic disease characterized by bilateral giant cell reparative granuloma of the jaws consisting of a fibrotic stroma with giant multinucleated cells (GMCs) and osteoclastic features. Cherubism severity is highly variable, and recurrence after surgery is the most important risk. Currently, there are no prognostic indicators. The aims of this study were to evaluate the osteoclastogenesis phenotype by histologic examination of nuclear factor of activated T cells 1 (NFATc1) localization and tartrate-resistant acid phosphatase (TRAP) activity and to correlate the results to disease aggressiveness to define prognostic indicators. Based on cherubism evolution 1 year after surgery, 3 classes of cherubism aggressiveness were identified: mild (group A), moderate (group B), and severe (group C). Histologically, in grade A and B cherubism lesions, GMCs were negative for both TRAP activity and NFATc1 nuclear localization. In contrast, in grade C cherubism lesions, GMCs were all positive for TRAP activity and NFATc1 nuclear localization and displayed osteoclast-like features. Other histopathologic findings were not different among the 3 groups. Our results establish that TRAP activity and NFTAc1 nuclear localization are associated with aggressive cherubism and therefore could be added to routine pathologic examination to aid in prognosis and management of the disease. The finding of NFATc1 nuclear localization in aggressive tumors supports the addition of anticalcineurin treatment to the therapeutic arsenal for cherubism.

The calcineurin inhibitor tacrolimus as a new therapy in severe cherubism

Cherubism is a rare genetic disorder characterized by extensive growth of a bilateral granuloma of the jaws, resulting in facial disfigurement. Cherubism is caused by gain-of-function mutations in the SH3BP2 gene, leading to overactivation of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1)-dependent osteoclastogenesis. Recent findings in human and mouse cherubism have suggested that calcineurin inhibitors might be drug candidates in cherubism medical treatment. A 4-year-old boy with aggressive cherubism was treated with the calcineurin inhibitor tacrolimus for 1 year, and clinical, radiological, and molecular data were obtained. Immunohistologic analysis was performed to compare preoperative and postoperative NFATc1 staining and tartrate resistant acid phosphatase (TRAP) activity. Real-time PCR was performed to analyze the relative expression levels of OPG and RANKL. After tacrolimus therapy, the patient showed significant clinical improvement, including stabilization of jaw size and intraosseous osteogenesis. Immunohistologic analyses on granuloma showed that tacrolimus caused a significant reduction in the number of TRAP-positive osteoclasts and NFATc1 nuclear staining in multinucleated giant cells. Molecular analysis showed that tacrolimus treatment also resulted in increased OPG expression. We present the first case of effective medical therapy in cherubism. Tacrolimus enhanced bone formation by stimulating osteogenesis and inhibiting osteoclastogenesis.

Clinical study evaluating the effect of bevacizumab on the severity of zoledronic acid-related osteonecrosis of the jaw in cancer patients

This study aimed to evaluate the effect of bevacizumab (BVZ) on the severity of osteonecrosis of the jaw (ONJ) in a cohort of cancer patients treated with intravenous zoledronic acid (ZA). We reviewed 42 oncologic patients with ONJ between 2007 and 2010. Only patients with solids tumors and who had received ZA were included. Data analyses included age, sex, underlying disease, ZA and BVZ dosages, dental history and ONJ characteristics. Of the 42 ONJ patients treated with ZA, 10 also received BVZ. In the 10 ZA/BVZ patients, the mean duration of ZA treatment at the time of ONJ diagnosis was 12.4 months (±6.8), compared to 22.9 months (±4.8) in the 32 patients who received ZA only (p<0.05). Cox's model analysis of the delay to ONJ diagnosis confirmed the impact of BVZ on ONJ diagnosis. In the ZA/BVZ-treated group, 7 (70%) patients developed spontaneous osteonecrosis. Multiple logistic regression analysis showed that ZA/BVZ is associated with increased risk of developing spontaneous ONJ (OR 6.07; 95% CI, [1.3-28.2], p<0.05). And finally, the number of ONJ lesions was increased in the ZA/BVZ-treated group compared to the ZA group (p<0.01). Other clinical conditions as type of tumor (prostate, breast…), cancer severity or other chemotherapy drugs also could be involved in ONJ evolution. However, this study demonstrates for the first time the potential negative influence of BVZ on the incidence and severity of ONJ in patients receiving ZA. Within the study limits, our results suggest that combination ZA/BVZ treatment may possibly predispose to the development of spontaneous and earlier ONJ.

Osteonecrosis of the Jaw and Nonmalignant Disease: Is There an Association with Rheumatoid Arthritis?

Objective.

To review cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) occurring in association with benign disease and to describe and compare the clinical course and outcome for patients with BRONJ and rheumatoid arthritis (RA) or osteoporosis.

Methods.

We retrospectively reviewed observations of all patients referred for treatment and followup for BRONJ from January 2007 to December 2011. Only patients with malignant disease were excluded. Demographic data, medical history, maxillofacial findings, BRONJ treatment, and followup were reviewed for each case.

Results.

Over a 5-year period, we diagnosed 112 patients with BRONJ. Among these patients, 15 received bisphosphonate (BP) treatment for nonmalignant disease (mean age 65.7 ± 19.8 yrs, 80% women). Patients received BP for a variety of reasons: 8 (53%) to prevent osteoporosis in association with underlying RA; 6 (40%) to prevent idiopathic osteoporosis; and 1 (7%) to treat ankle algodystrophy. The mean oral BP exposure period was 48.4 months (median 36 mo). In 13 cases (86.6%), BRONJ was diagnosed following dental extraction. Of the 8 patients with RA, 5 (62.5%) were taking prednisone at the time of the discovery of BRONJ. Major surgery, sequestrectomy, or alveolectomy was performed in 9 patients (60%), all of whom healed within 3 to 36 months (mean 11.5 mo). Comparative analysis of all the variables showed no statistically significant differences between patients with RA and others.

Conclusion.

ONJ is a rare adverse effect of BP therapy, especially when administered orally. Within the limits of our study, we were unable to demonstrate a difference in BRONJ disease spectrum, clinical course, or outcome between patients with and those without RA.

[Pediatric keratocystic odontogenic tumor and nevoid basal cell carcinoma syndrome. Predictive factors for recurrence and aggressiveness]

INTRODUCTION

Keratocystic odontogenic tumors (KOT), as complications in Nevoid Basal Cell Carcinoma Syndrome (NBCCS), occur early (before 20 years of age) and are usually more aggressive. The aim of this retrospective study was to determine the clinical, histological, and genetic phenotype, of these lesions and to define predictive features of aggressiveness.

PATIENTS AND METHODS

We retrospectively studied five patients presenting with one or several KOT with NBCCS. We collected their clinical, radiological, and therapeutic data, rate of recurrence or new localization. Anatomopathological examinations were reviewed systematically. Somatic PTCH, SMO and SMAD 4 sequencing were completed.

RESULTS

The average age at diagnosis was 11.2 years. The average number of KOT was 3.2 most often located in the molar region. All the cysts were enucleated. Anatomopathological examination revealed the presence of satellite cysts and daughter cysts and epithelial expansion in more than 80% of cases. No somatic mutation was observed among KOT.

DISCUSSION

KOT develop in the first 10 years, in patients presenting with NBCCS, and recurrence is observed in the second and third decade. KOT are typically aggressive and have a tendency to recur, especially in patients with NBCCS. Anatomopathological examination may be predictive of the lesion's aggressiveness. Understanding the genetic and immunological mechanisms should open the way for new medical treatment.

Osteoclasts in the dental microenvironment: a delicate balance controls dental histogenesis

The impact of osteoclast activity on dental development has been previously analyzed but in the context of severe osteopetrosis. The present study sought to investigate the effects of osteoclast hypofunction,present in Msx2 gene knockin mutant mice (Msx2-/-), and hyperfunction, in transgenic mice driving RANK over-expression in osteoclast precursors (RANK(Tg)), on tooth development. In Msx2-/- mice, moderate osteopetrosis was observed, occurring exclusively in the periodontal region. Microradiographical and histological analyses revealed an abnormal dental epithelium histogenesis that gave rise to odontogenic tumor-like structures. This led to impaired tooth eruption, especially of the third mandibular molars. In RANK(Tg) mice, root histogenesis showed site-specific upregulation of dental cell proliferation and differentiation rates. This culminated in roots with a reduced diameter and pulp size albeit of normal length. These two reverse experimental systems will enable the investigation of distinctive dental cell and osteoclast communication in normal growth and tumorigenesis.

Efficacy of topical 1% lidocaine in the symptomatic treatment of pain associated with oral mucosal trauma or minor oral aphthous ulcer: a randomized, double-blind, placebo-controlled, parallel-group, single-dose study

AIMS

To determine the efficacy in pain reduction of a topical 1% lidocaine compared to a placebo cream in patients with oral mucosal lesions due to trauma or minor oral aphthous ulcer.

METHODS

The design was a double-blind, randomized, placebo-controlled, six-center trial on 59 patients. Pain intensity and relief were measured using a 100-mm visual analog scale (VAS). One-tailed Student t test and ANOVA analyses were used for statistical analyses.

RESULTS

Independent of the pain origin (oral mucosal trauma or minor oral aphthous ulcer), the application of the 1% lidocaine cream led to a mean reduction in VAS pain intensity of 29.4 mm ± 17.0, which was significantly greater than the decrease obtained with the placebo cream. Analysis showed a statistically significant efficacy of the 1% lidocaine cream (P = .0003). Its efficacy was not related to the type of lesion, and no adverse drug reaction, either local or systemic, was reported by any of the patients.

CONCLUSION

A significant reduction in pain intensity occurred after application of 1% lidocaine cream and was significantly greater than that with the placebo cream. Taking into account the study's limitations, this product seems safe to use.

Enamel protein regulation and dental and periodontal physiopathology in MSX2 mutant mice

Signaling pathways that underlie postnatal dental and periodontal physiopathology are less studied than those of early tooth development. Members of the muscle segment homeobox gene (Msx) family encode homeoproteins that show functional redundancy during development and are known to be involved in epithelial-mesenchymal interactions that lead to crown morphogenesis and ameloblast cell differentiation. This study analyzed the MSX2 protein during mouse postnatal growth as well as in the adult. The analysis focused on enamel and periodontal defects and enamel proteins in Msx2-null mutant mice. In the epithelial lifecycle, the levels of MSX2 expression and enamel protein secretion were inversely related. Msx2+/- mice showed increased amelogenin expression, enamel thickness, and rod size. Msx2-/- mice displayed compound phenotypic characteristics of enamel defects, related to both enamel-specific gene mutations (amelogenin and enamelin) in isolated amelogenesis imperfecta, and cell-cell junction elements (laminin 5 and cytokeratin 5) in other syndromes. These effects were also related to ameloblast disappearance, which differed between incisors and molars. In Msx2-/- roots, Malassez cells formed giant islands that overexpressed amelogenin and ameloblastin that grew over months. Aberrant expression of enamel proteins is proposed to underlie the regional osteopetrosis and hyperproduction of cellular cementum. These enamel and periodontal phenotypes of Msx2 mutants constitute the first case report of structural and signaling defects associated with enamel protein overexpression in a postnatal context.

Physiopathology of dental rickets in vitamin D receptor-ablated mice

1α25(OH)(2)vitaminD(3) and its nuclear receptor, VDR, are essential for normal tooth development. However, the relative contributions of the direct vs. indirect effects of vitamin D action on odontogenesis are unclear. The aim of this study was to discriminate among the specific roles of 1α25(OH)(2) vitaminD(3), calcemia/phosphatemia, and the maternal environment in mouse VDR null mutants. Microradiographic, histological, and molecular analyses were conducted on adult mice under hypocalcemic/hypophosphatemic vs. normocalcemic/normophosphatemic conditions, and pups of first- (VDR-/- born to VDR+/- dams) vs. second-generation (VDR-/- born to VDR-/- dams) mice. In VDR-/- mice, crown morphogenesis was affected exclusively in second-generation pups. In first-generation adult VDR-/- mice, both enamel and dentin were affected, and pathologic features of root resorption in both apical and cervical regions were observed. Nutritional calcium and phosphate normalization completely rescued the root resorption and partially rescued the dentin and enamel phenotypes (altered cell differentiation and matrix protein expression). Analysis of these data illustrates the co-existence of different pathways of vitamin D action in tooth differentiation and biomineralization. These targeted and cumulative effects would generate the diverse and wide spectrum of dental rickets phenotypes.

[Maxillary and mandibular carcinogenesis: research and prospects]

Development and growth of odontogenic tumours depend on impairment of numerous genes and molecules. In recent years, most of the genes involved in dental development were identified. This produced a new basis for the study of oral pathology and maxillofacial carcinogenesis. A better understanding of these molecular phenomena should allow to better determine the evolution of such lesions. Research breakthroughs should facilitate the development of new molecular and genetic therapeutic perspectives.

Reduced susceptibility to amoxicillin of oral streptococci following amoxicillin exposure

As antibiotic pressure often triggers bacterial resistance, the use of short-duration therapies is increasingly recommended. The objective of the present study was to evaluate both the clinical efficiency and the impact on oral streptococci of a 3 day versus a 7 day amoxicillin therapy for odontogenic infection requiring tooth extraction. On day 0, patients were randomly assigned to a 3 day or 7 day amoxicillin treatment. The tooth was extracted on day 2 and the post-operative follow-up was carried out on day 9. Oral flora was collected on days 0, 9 and 30, and the susceptibility of the streptococci to amoxicillin was determined. The results showed that treatment with amoxicillin for 3 or 7 days had a similar clinical efficiency, and also induced similar selection of oral streptococci with reduced susceptibility to amoxicillin, suggesting that the selection of strains with reduced susceptibility to amoxicillin is a rapid phenomenon, appearing even with short-duration therapies.

Vitamin D and tissue non-specific alkaline phosphatase in dental cells

Dental epithelium comprises different cell populations, including ameloblasts and stratum intermedium cells. Ameloblasts are vitamin D targets, and at least five proteins undergo specific modulation of their expression following the addition of 1alpha,25(OH)2 vitamin D3[1alpha,25(OH)2D3]. Stratum intermedium cells have not been studied in any great detail regarding vitamin D impact. Interestingly, in these cells, the tissue non-specific alkaline phosphatase (TNAP) is overexpressed. On the other hand, TNAP is a reliable bone marker of vitamin D action, similar to calbindins in kidney and intestine, previously used for studies of vitamin D activity in ameloblasts. Here, TNAP expression and activity were investigated in vivo in the microdissected epithelium and mesenchyme of mandible incisors. Physiological doses of 1alpha,25(OH)2D3 injected in control rats failed to modify TNAP activity in both dental epithelium and mesenchyme. No significant differences were observed in the steady-state levels of TNAP mRNAs of dental tissues from wild-type and vitamin D nuclear receptor (VDRnuc)-deficient mice of the same litters. These data suggest that, in contrast to ameloblasts, stratum intermedium cells are not sensitive to 1alpha,25(OH)2D3. An explanation for such a responsiveness of stratum intermedium cells to 1alpha,25(OH)2D3 is proposed based on the respective expressions of both vitamin D receptors (VDRnuc and 1,25D3-[MARRS]) and the Dlx2 homeobox gene.

Does Vitamin D play a role on Msx1 homeoprotein expression involving an endogenous antisense mRNA?

Msx1 homeobox gene, a member of Msx family, has been implicated in numerous organs. Its participation was established in different events, such as morphogenetic field determinism and epithelio-mesenchymal interactions. Most of Msx1 target organs are also known for their sensitivity to Vitamin D: such as bone, tooth germ, and hair follicle. Whereas, the expression of Msx2, another member of Msx family, has been shown to be controlled by Vitamin D, no information is available for Msx1. This study aims to analyze the potential relationships between Vitamin D and Msx1 through: (1) comparative analysis of Vitamin D receptor (VDR) and Msx1 protein expression, (2) investigation of Msx1 expression in VDR null mutant mice, and (3) study of Msx1 overexpression impact on osteocalcin VDR expression in immortalized MO6-G3 odontoblasts. Results show the existence of cross-talks between Vitamin D and Msx1 regulation pathways. In odontoblastic cells, Msx1 overexpression decrease VDR expression, whereas in rickets Msx1 sense transcript expression is decreased. These cross-talks may open a new window in the analysis of rickets mineralized tissues physiopathology. In Vitamin D null mutants, the study of the natural Msx1 antisense transcript which has been recently described should be informative.

Cross-talk between Msx/Dlx homeobox genes and vitamin D during tooth mineralization

Rickets is associated with site-specific disorders of enamel and dentin formation, which may reflect the impact of vitamin D on a morphogenetic pathway. This study is devoted to potential cross-talk between vitamin D and Msx/Dlx transcription factors. We raised the question of a potential link between tooth defects seen in mice with rickets and Msx2 gene misexpression, using mutant mice lacking the nuclear vitamin D receptor as an animal model. Our data showed a modulation of Msx2 expression. In order to search for a functional impact of this Msx2 misexpression secondary to rickets, we focused our attention on osteocalcin as a target gene for both vitamin D and Msx2. Combining Msx2 overexpression and vitamin D addition in vitro, we showed an inhibitory effect on osteocalcin expression in immortalized MO6-G3 odontoblasts. Finally, in the same cells, such combinations appeared to modulate VDR expression outlining the existence of complex cross-regulations between vitamin D and Msx/Dix pathways.