Mechanical frequency and stimulation-site-related differences in vibrotactile detection capacity along the lip vermilion in young adults

Accurate clinical assessment of the infraorbital and mental branch of the trigeminal nerve is aided by an appreciation of the variations in sensitivity that may exist along the surface of the perioral region under examination. The purpose of this investigation was to map the mediolateral spatial and frequency variations in vibrotactile detection capacity to inputs delivered to the upper lip (UL) and lower lip (LL) vermilion. Mechanical vibrotactile inputs at frequencies of 5, 10, 50, and 150 Hz were delivered to three locations on the vermilion of the UL and LL: midsagittally and laterally (left and right) at a point halfway between the midsagittal plane and the oral angle. An adapted staircase tracking method was used to converge upon a threshold value for each test frequency at each stimulation site. The results indicated that midsagittal vermilion sites were significantly more sensitive to our range of vibrotactile inputs compared to lateral vermilion locations. In addition, no significant differences in sensitivity as a function of laterality or between the UL and LL vermilion sites were noted. Greater midline sensitivity to vibrotactile stimulation suggests that receptive fields at this location may be of greater density and/or demonstrate greater overlap compared to lateral vermilion sites. Both investigators contributed equally to this report and should be considered co-first authors.     

Anterior mandibular apical base augmentation in the surgical orthodontic treatment of mandibular retrusion

The authors describe a surgical technique alternative to traditional pre-surgical orthodontics in order to increase the apical base in mandibular retrusion (class II, division I). This subapical osteotomy, optimizing inferior incisal axis without dental extractions and a long orthodontic treatment, associated to genioplasty permits to obtain an ideal labio-dento-mental morphology. This procedure avoids in some cases the need of a mandibular advancement and, if necessary, it reduces his entity with obvious advantages.     

Salivary thromboplastic activity in diabetics and healthy controls

Coagulative function of saliva derives from the thromboplastin found in saliva. It may establish hemostasis in the mouth. Salivary disfunction and changes in salivary composition and are frequent complications of diabetes. This study investigated the influence of some local etiologic and systemic factors on salivary thromboplastic activity (STA) in diabetics. In this study, cytological smears and biochemical tests were used. STA was measured by Quicks one stage method, serum glucose by the glucose oxidase method, and salivary protein by the method of Lowry. STA was almost the same in the diabetic and control groups. The only statistically significant difference within the diabetic group was found to be due to antibiotic usage. STA, i.e. clotting time, was 30% longer (114 s) (p<0.05) and salivary protein (4.07 mg ml^-1) (p<0.1) was lower in diabetics not taking antibiotics than in those taking them. No such differences were observed in the healthy controls. Significant linear correlations (p<0.05) with respect to STA were with salivary protein in the control group (r=0.61) and in the diabetic group (r=0.51) and with antibiotic usage (r=0.29), with leukocyte cell count (r=0.27) in the diabetic group. It can be concluded that salivary cells, proteins and antibiotic usage are important for STA.     

Effects of induced periapical abscesses on rat pregnancy outcomes

Objective

The objective of this study was to determine the effects of induced periapical abscesses on pregnant rats.

Design

In 1/2 of the animals (n = 16), the pulps of the maxillary right molars were exposed to the oral environment, which resulted in a periapical abscess. The other 1/2 (n = 16) were sham-operated. 1/2 of the animals of both groups became pregnant 2 weeks later. The pregnancy duration, and weight and number of pups were assessed at delivery. Serum, liver and uterine horn samples were taken from all animals at euthanasia and serum IL-6, endothelin-1, TNF-α, IL-10, cortisol and insulin were determined by ELISA. Liver concentrations of IL-6, CRP and IL-6 and uterine horn concentrations of IL-6, vascular endothelial growth factor (VEGF), TNF-α, IL-10 and IL-1-β were assessed by ELISA. Blood glucose concentrations were determined using a glucometer. Outcome variables were compared by factorial ANOVA, a post hoc Tukey test, and Pearson’s correlation test.

Results

Pregnant rats with periapical abscesses had a significantly longer pregnancy and delivered pups with a significantly higher birthweight (p < 0.05). They had significantly higher concentrations of IL-6, VEGF, IL-1-β, and IL-10 within the uterine horn and IL-6, CRP and TNF-α within the liver (p < 0.01). Blood glucose and serum TNF-α, IL-6, endothelin-1, IL-10, and insulin concentrations were significantly higher in the pregnant animals with pulpal abscesses (p < 0.01).

Conclusion

The significant increase in serum TNF-α, taken together with significant increases in blood glucose and serum insulin concentrations, suggest that animals with induced periapical abscesses developed insulin resistance, which significantly affected their pregnancy outcomes.     

The strengthening mechanism of resin cements on porcelain surfaces

All-ceramic crowns bonded with resin cements have increased performance, and two theories have been proposed. Marquis (1992) suggested that the resin modified defects by crack healing, while Nathanson (1993) proposed that resin polymerization shrinkage strengthened porcelains. Both theories imply a sensitivity of strengthening to defect size. The hypothesis tested was that resin strength enhancement is independent of defect severity. We ground 200 porcelain discs to remove imperfections and indented 120 to create a large defect. Discs were tested dry, wet, and after being coated with 75-100 microm of resin cement in bi-axial flexure. Disc strength with and without indentations was increased significantly when coated with 2 resin cements. Both cements significantly increased the strength independent of defect population, and the hypothesis was accepted. It is proposed that the combination of surface pre-treatment and cement moved the fracture origin from the porcelain/cement interface to the cement surface, consistent with resin strength enhancement independent of defect severity.     

A proposal for a new classification of lesions of exposed tooth surfaces

In the presence of improved methods of identification and treatment of lesions on the exposed surfaces of teeth, it should now be acknowledged that the GV Black "classification of carious cavities" is out of date. This paper describes a new system, proposed in 1997, discussed broadly throughout the profession, and eventually modified. The system has been adopted in several regions around the world as being a useful corollary to the current developing concept of minimal intervention dentistry. It is now desirable to adopt a new approach to the identification and recording of the lesions caused by both caries and non-carious tooth loss. A major advantage arising from its adoption would be that it would encourage the profession to minimise the amount of normal healthy tooth structure that is often sacrificed in pursuit of the cavity designs as suggested by Black. The authors are members of a Project Group of the FDI Science Committee, and this paper explains the concept and offers justification for the adoption of the system.     

Severe proliferative congenital temporomandibular joint ankylosis: a proposed treatment protocol utilizing distraction osteogenesis

The classical treatment for temporomandibular joint (TMJ) ankylosis in children: 1) joint release; 2) arthroplasty; 3) reconstruction; and 4) postoperative physical therapy (PT), is often unsuccessful. Postoperative physical therapy is difficult in the young patient due to poor cooperation. Moreover, there is a subgroup of patients who have a refractory congenital proliferative bony process that is the cause of their disease. In these patients, a role for distraction osteogenesis (DO) has been defined. We present a series of young patients with congenital proliferative TMJ ankylosis. Some have failed classic treatment. In such cases, DO is used to expand the mandibular size and soft tissue matrix. This creates a static open bite, facilitates mid-facial growth, and avoids compromise of the airway, speech, nutrition, and oral hygiene. To maintain these objectives, mandibular DO may be repeated as the child matures. Once skeletal maturity is reached, DO is used to normalize occlusion and further expand the soft tissue envelope prior to definitive reconstruction and aggressive post-op PT. In seven patients, this protocol has been used. Five patients are currently in the active phase of growth and undergoing interim treatment with mandibular DO. Two patients have reached skeletal maturity and have completed the protocol of DO with definitive arthroplasty and reconstruction. DO is a valuable aid in the treatment of the problematic child with congenital proliferative TMJ ankylosis. Interim DO, prior to definitive arthroplasty and reconstruction, can provide a static open bite that prevents progressive deformity and its associated functional disturbances.     

Technology Development to Explore the Relationship Between Oral Health and the Oral Microbial Community

The human oral cavity contains a complex microbial community that, until recently, has not been well characterized. Studies using molecular tools have begun to enumerate and quantify the species residing in various niches of the oral cavity; yet, virtually every study has revealed additional new species, and little is known about the structural dynamics of the oral microbial community or how it changes with disease. Current estimates of bacterial diversity in the oral cavity range up to 700 species, although in any single individual this number is much lower. Oral microbes are responsible for common chronic diseases and are suggested to be sentinels of systemic human diseases. Microarrays are now being used to study oral microbiota in a systematic and robust manner. Although this technology is still relatively young, improvements have been made in all aspects of the technology, including advances that provide better discrimination between perfect-match hybridizations from non-specific (and closely-related) hybridizations. This review addresses a core technology using gel-based microarrays and the initial integration of this technology into a single device needed for system-wide studies of complex microbial community structure and for the development of oral diagnostic devices.