Catherine Millet

Background: The rapid development of artificial intelligence systems (AIS) in prosthodontics requires an overview of their applications, capabilities, opportunities and challenges. Methods: This narrative review provides insights into AIS in prosthodontics and their applications. AI systems were classified into five main categories: (1) automated image handling and annotation; (2) classification and decision support; (3) visualisation and modelling; (4) optimisation and simulation; and (5) recording and communication. Results: These AIS in prosthodontics can be used to delineate restorative margins in computer‐aided design and manufacturing workflows, digital restoration design to generate crown proposals from intraoral scanning data, or conversational interfaces to provide clear, accessible and personalised explanations to patients. These systems offer significant capabilities, such as in diagnostic and treatment planning support, optimisation of prosthetic design, improved efficiency of digital workflows and enhanced patient communication. However, important challenges must be considered including the risk of automation bias, the lack of system transparency and explainability, issues related to equity and data protection and the ethical and medico‐legal uncertainties surrounding accountability in the event of treatment failure. Conclusions: These systems offer significant capabilities in prosthodontics, but important challenges must be considered.

Key points: Our study contributes to the characterization of muscle loss and weakness processes induced by a sedentary life style, chronic hypoactivity, clinical bed rest, immobilization and microgravity. This study, by bringing together integrated and cellular evaluation of muscle structure and function, identifies the early functional markers and biomarkers of muscle deconditioning. Three days of muscle disuse in healthy adult subjects is sufficient to significantly decrease muscle mass, tone and force, and to induce changes in function relating to a weakness in aerobic metabolism and muscle fibre denervation. The outcomes of this study should be considered in the development of an early muscle loss prevention programme and/or the development of pre‐conditioning programmes required before clinical bed rest, immobilization and spaceflight travel. Microgravity and hypoactivity are associated with skeletal muscle deconditioning. The decrease of muscle mass follows an exponential decay, with major changes in the first days. The purpose of the study was to dissect out the effects of a short‐term 3‐day dry immersion (DI) on human quadriceps muscle function and structure. The DI model, by suppressing all support zones, accurately reproduces the effects of microgravity. Twelve healthy volunteers (32 ± 5 years) completed 3 days of DI. Muscle function was investigated through maximal voluntary contraction (MVC) tests and muscle viscoelasticity. Structural experiments were performed using MRI analysis and invasive experiments on muscle fibres. Our results indicated a significant 9.1% decrease of the normalized MVC constant (P = 0.048). Contraction and relaxation modelization kinetics reported modifications related to torque generation (k_ACT = −29%; P = 0.014) and to the relaxation phase (k_REL = +34%; P = 0.040) after 3 days of DI. Muscle viscoelasticity was also altered. From day one, rectus femoris stiffness and tone decreased by, respectively, 7.3% (P = 0.002) and 10.2% (P = 0.002), and rectus femoris elasticity decreased by 31.5% (P = 0.004) after 3 days of DI. At the cellular level, 3 days of DI translated into a significant atrophy of type I muscle fibres (−10.6 ± 12.1%, P = 0.027) and an increased proportion of hybrid, type I/IIX fibre co‐expression. Finally, we report an increase (6‐fold; P = 0.002) in NCAM+ muscle fibres, showing an early denervation process. This study is the first to report experiments performed in Europe investigating human short‐term DI‐induced muscle adaptations, and contributes to deciphering the early changes and biomarkers of skeletal muscle deconditioning.

Background Vertebral deconditioning is commonly experienced after space flight and simulation studies. Disc herniation (DH) is quadrupled after space flight. Purpose The main hypothesis formulated by the authors is that microgravity results in intervertebral disc swelling. Study Design The aim of the study was to identify the morphological changes of the spine and their clinical consequences after simulated microgravity by 3-day dry immersion (DI). The experimental protocol was performed on 12 male volunteers using magnetic resonance imaging and spectroscopy before and after DI. Methods All the experiment was financially supported by CNES (Centre national d’études spatiales i.e. French Space Agency). Results We observed an increase in rachis height of 1.5 ± 0.4 cm and a decrease in curvature, particularly for the lumbar region with a decrease of -4 ± 2.5°. We found a significant increase in intervertebral disc (IVD) volume of +8 ± 9% at T12-L1 and +11 ± 9% at L5-S1. This phenomenon is likely associated with the increase in disc intervertebral water content (IWC), 17 ± 27%. During the 3 days in DI, 92% of the subjects developed back pain in the lumbar region below the diaphragmatic muscle. This clinical observation may be linked to the morphological changes of the spine. Conclusions The morphological changes observed and, specifically, the disc swelling caused by increased IWC may contribute to understanding disc herniation after microgravity exposure. Our results confirmed the efficiency of the 3-day DI model to reproduce quickly the effects of microgravity on spine morphology. Our findings raise the question of the subject selection in spatial studies, especially studies about spine morphology and reconditioning programs after space flight. These results may contribute to a better understanding of the mechanisms underlying disc herniation and may serve as the basis to develop countermeasures for astronauts and to prevent IVD herniation and back pain on Earth.

The objective of the study was to determine the influence of simulated microgravity by exposure to dry immersion on the craniomandibular system. Twelve healthy male volunteers participated in a 3-day dry immersion study. Before and immediately after exposure we measured maximal bite force using piezoresistive sensors. The mechanical properties of the jaw and cervical muscles were evaluated before, during, and after dry immersion using MyotonPRO. Because recent studies reported the effects of jaw motor activity on the postural stability of humans, stabilometric measurements of center of pressure were performed before and after dry immersion in two mandibular positions: rest position without jaw clenching, and intercuspidal position during voluntary teeth clenching. Results revealed no significant changes of maximal bite force after dry immersion. All postural parameters were significantly altered by dry immersion. There were however no significant differences in stabilometric data according to mandibular position. Moreover the masseter tonicity increased immediately after the end of dry immersion period. Dry immersion could be used as a valid model for studying the effects of microgravity on human subjects. However, 3 days appear insufficient in duration to evaluate the effects of weightlessness on maximal bite force. Our research suggests a link between postural disturbance after dry immersion and masseter tonicity.

This manuscript describes an interdisciplinary approach over a period of 8 years combining surgical and prosthodontic treatment of a young patient diagnosed with hypocalcified‐type amelogenesis imperfecta and anterior open bite. The treatment procedures included transitional restorations, orthodontic treatment, and maxillofacial surgery with a one‐piece Le Fort I osteotomy, bilateral mandibular osteotomy, and genioplasty. The definitive prosthetic rehabilitation consisted of 28 zirconia‐based ceramic single crowns restoring both esthetics and function. Photographs and radiographs associated with clinical evaluation were used in the maintenance period. Two‐year follow‐up revealed satisfactory results and no deterioration in the restorations.

Aim: To present a case of multidisciplinary management and fixed rehabilitation of a young girl with amelogenesis imperfecta (AI), a severe open bite and occlusal instability. Background: AI is a genetic disorder characterized by enamel malformations, disturbances in tooth eruption and significant attrition. Early diagnosis is essential, since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. As AI is frequently accompanied by unesthetic appearance, open bite deformity and malocclusion, a multidisciplinary approach is often required. Case report: This clinical report describes the condition and presents the case of a 10-year-old girl with hypocalcified form of AI. Orthodontic treatment and orthognathic surgery were performed as part of the prosthetic treatment plan to achieve acceptable and durable results. They consisted of correcting class II, posterior crossbite and anterior open bite with a fixed orthodontic appliance, Lefort I osteotomy, bilateral mandibular ramus osteotomy and genioplasty. Prosthodontics treatment consisted of metal-ceramic crowns with low-fusing ceramic for good long-term results. No deterioration in the rehabilitation was found after 5 years of follow-up. Conclusion: Complete restoration of severe AI is a long and complex process generally extending over several years. Clinical significance: This article shows the important role of interdisciplinary approach to treating a patient with AI over a period of 8 years. How to cite this article: Millet C, Duprez JP. Multidisciplinary Management of a Child with Severe Open Bite and Amelogenesis Imperfecta. J Contemp Dent Pract 2013;14(2): 320-326.

doi: 10.1111/j.1741‐2358.2011.00564.xSurgical and prosthetic treatment in an elderly patient affected by unilateral idiopathic gingival fibromatosis: a case reportObjectives:  The aim was to present the diagnosis and treatment of a case of unilateral idiopathic gingival fibromatosis (IGF) in a geriatric patient.Background:  IGF is a rare condition characterised by an enlargement of the attached and marginal gingivae with no obvious association to any causative factor. Gingival overgrowth causes inaesthetic changes and clinical symptoms such as speech disturbances, tooth movement, and occlusal problems.Materials and methods:  A 65‐year‐old female presented localised enlargement of mandibular gingiva, malpositioning of anterior mandibular teeth, and difficulty in speech and mastication. IGF also causes numerous aesthetic and psychological problems. Treatment consisted of multiple extractions, surgical therapy, and early prosthetic rehabilitation to restore function and appearance and to prevent recurrence.Results:  Excellent aesthetic result and psychological benefit were achieved, and no fibromatosis recurrence was detected after 1 year following surgery.Conclusion:  Gingival resection of the tissue excess and early oral rehabilitation with removable dentures have so far greatly improved patient’s quality of life.