Ascending connections from the caudal part to the oral part of the spinal trigeminal nucleus in the rat.

The brainstem trigeminal somatosensory complex, while sharing many common aspects with the spinal somatosensory system, displays features specific to orofacial information processing. One of those is the redundant representation of peripheral structures within the various subnuclei of the complex. A functional redundancy also exists since a single sensory modality, e.g. nociception, may be processed within different subnuclei. In the present study, we addressed the question whether anatomical connections from the caudal part to the oral part of the spinal trigeminal nucleus may support topographical and functional redundancy within the rat trigeminal somatosensory complex. The retrograde tracer tetramethylrhodamine-dextran was injected iontophoretically into the oral subnucleus of anaesthetised rats. Cell bodies labelled retrogradely from the oral subnucleus were observed in laminae III-IV and V of the ipsilateral caudal subnucleus consistently, and to a lesser degree in lamina I. Such a distribution of retrogradely labelled cells suggested that specific subsets of neurones may relay nociceptive information, and others non-nociceptive information. Furthermore, intratrigeminal connections conserved the somatotopic distribution of primary afferents in the two subnuclei. First, injections of tracer in the dorsomedial and ventrolateral parts of the oral subnucleus resulted in retrograde labelling of the dorsal and ventral parts of the caudal subnucleus respectively. Second, animals that received tracer into the ventrolateral oral subnucleus displayed more caudal labelling than animals that were injected into the dorsomedial oral subnucleus. These findings show the existence of anatomical connections from the caudal part to the oral part of the spinal trigeminal nucleus in the rat. The connections conserve the somatotopic distribution of primary afferents in the two subnuclei. They provide an anatomical substrate for the indirect activation of trigeminal oral subnucleus neurones by somatosensory stimuli through the caudal subnucleus.

Caries management decision: influence of dentist and patient factors in the provision of dental services.

OBJECTIVES: Little is known about how dentists implement caries management and provide restorative dental services in everyday practice. This study explored whether or not recent concepts in caries management were implemented in practice by private practitioners. The influence of patient and practitioner characteristics on the provision of restorative dental services was also investigated through multidimensional analyses. METHODS: A sample of French general private dental practitioners was asked to record the characteristics of 35 preventive or restorative treatments made on vital permanent teeth. The data collection form was designed to explore dentists' attitudes towards caries management and their use of minimally invasive therapies. RESULTS: Twenty-six practitioners recorded the characteristics of 921 treatments performed on 457 patients. Results indicate that participants rarely performed non-invasive treatments. They used an inappropriate detection tool, as most of decisions to treat were based on visual inspection frequently associated with probing. Multidimensional analysis showed that dentists provided different restorative treatments depending on patient characteristics, with minimally invasive, esthetic restorations preferentially performed for healthy, young and well-insured patients. Restorative treatments and detection tools also varied markedly among practitioners. These variations in service patterns were not related to a specific patient profile in each dental practice. CONCLUSIONS: Results indicate that recent concepts in caries management have not yet been adopted in everyday practice. Patient and dentist characteristics influence the provision of restorative dental services. Decision-making in caries management not only depends on pathophysiology but also seems to be influenced by many other factors.

Clinical evaluation of the Carisolv chemomechanical caries removal technique according to the site/stage concept, a revised caries classification system.

The objective of the present study was to assess the efficiency and benefit of a chemomechanical system for carious dentin removal, Carisolv, in general practice. A revised caries classification, the site/stage concept, was used to describe the clinical situations of all carious lesions treated. The study was performed by 12 investigators, and 120 carious lesions were treated with Carisolv. Sixty percent of the cases were treated without anaesthesia, and we found a significant correlation between chemomechanical treatment without anaesthesia and absence of pain ( P=0.01). In 78.3% of the cases, carious dentin was totally removed with Carisolv, and in 21.7%, the dentin treatment was completed by drilling. In cases performed with Carisolv alone, the time required to remove carious dentin was 11.1+/-9.51 min (mean+/-SD). Treatment time was equivalent for all sites and increased significantly with each successive stage of lesion progression ( P<0.001). In 82.5% of cases, the clinicians were satisfied with Carisolv, and in 99.2%, so were the patients. We conclude that, using clinical examination methods, Carisolv seems to remove carious dentin at all sites and stages of carious lesions but must be made more efficient for use in general practice.