Sialolithiasis in a residual Wharton's duct after excision of a submandibular salivary gland.

Treatment of salivary stones includes both surgical and non-surgical techniques. Surgical approaches range from excision of the sialolith, for those near the duct orifice, to removal of the affected salivary gland and its associated duct, for stones near the hilum of the gland. We present a case of two sialoliths triggering an acute infection in a residual Wharton's duct, 12 years after the removal of the associated submandibular gland. Excision of the sialoliths and treatment of the infected duct via sialodochoplasty was successfully performed in this patient. If the Wharton's duct is not removed with the associated submandibular gland, the potential for infection and continuous growth of dormant calcifications exists. We also address the aetiology, pathogenesis, and management of patients with sialolithiasis in the absence of a major salivary gland.

Effects of sphingosine-1-phosphate and lysophosphatidic acid on human osteoblastic cells.

The effects of the lysophospholipids, sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) were studied in human primary osteoblastic cells and the human osteosarcomal cell lines, G292 and MG-63. The studies focused on the role of the Gi protein in the regulation of S1P and LPA-induced proliferation, the effects of the phospholipids on alkaline phosphatase, an early marker of osteoblastic cell proliferation, and the presence of edg receptors. Proliferation was assessed by 3H-thymidine incorporation. Short-term incubation with S1P or LPA induced increases in proliferation that were attenuated in the presence of the Gi inhibitor, pertussis toxin. Alkaline phosphatase activity was measured with a spectrophotometric assay. Biphasic effects of S1P and LPA were observed with the nature of the response dependent upon the cell type, concentration of test agent and the time period of incubation. RTPCR studies revealed that edg-1,2,4,5 receptors are present in the primary normal osteoblastic cells, the MG63 and G292 cells. Only the G292 cells expressed the edg-3 receptor to any significant extent.

Role of protein kinase C alpha in primary human osteoblast proliferation.

Protein kinase C (PKC) isoforms have been shown to have specific expression profiles and individual isoforms are believed to play distinct roles in the cells in which they are found. The goal here was to determine which specific isoform(s) is involved in proliferation of primary human osteoblasts. In primary human osteoblasts, 10 microM of acute sphingosine-1-phosphate (S1P) treatment induced an increase in proliferation that correlated with an increase in PKCalpha and PKCiota expression. To further delineate which isoforms are involved in osteoblastic cell proliferation, the effect of low versus high serum culture conditions on PKC isoform expression was determined. Likewise, the effect of antisense oligodeoxynucleotides (ODNs) to specific PKC isoforms on proliferation and MAPK activation was studied. The effect of S1P on intracellular translocation of activated PKC isoforms was also evaluated. The results indicated that in primary human osteoblasts, PKCalpha was not expressed under conditions of low proliferative rate while PKCdelta and PKCiota expression was not affected. The specific inhibition of PKCalpha by antisense ODNs resulted in inhibition of MAPK activity leading to a significant decrease in proliferation. S1P up-regulated antisense ODN inhibited PKCalpha expression and MAPK activity and led to an increase in proliferation. Subsequent experiments using platelet-derived growth factor (PDGF) as an additional mitogen generated similar data. PDGF stimulation resulted in a significant increase in proliferation that correlated with an up-regulation of inhibited PKCalpha expression in antisense ODN-treated cells. Immunofluorescence methods showed that mitogenic stimulation of PKCa resulted in nuclear translocation. Our findings present original data that PKCalpha is the isoform specifically involved in the proliferation of primary human osteoblasts.

Sphingosine-1-phosphate effects on PKC isoform expression in human osteoblastic cells.

Sphingosine-1-phosphate (S1P) has been shown to participate in the proliferative process in human osteoblasts.(1) The mitogenic effect of S1P has been postulated to involve two signaling pathways, the Gi linked protein receptor pathway and the PKC pathway. To define the possible role of PKC isoforms in osteoblastic cell proliferation, the effects of S1P on PKC isoform expression was determined. While PKC lambda was minimally detected, the isoforms alpha, delta and iota were all found to be highly expressed by the human osteoblast. In human osteoblastic cells, S1P induced a 25% increase in the expression of PKC alpha and approximately a 30% increase in the expression of PKC iota. S1P did not have an effect on PKC delta expression. Pretreatment with pertussis toxin (PT) led to an inhibition of the observed S1P effects on the expression of the alpha and iota isoforms.

Bone regeneration with a calcium sulfate barrier.

OBJECTIVES: Bone defects are a challenge for the dental clinician. As widely accepted in guided tissue regeneration, physically halting soft connective tissue proliferation into bone allows for bone regeneration. This concept is the "osteopromotion principle." The aim of this study was to assess the osteopromoting effect of calcium sulfate as a barrier. STUDY DESIGN: Forty male Sprague-Dawley rats were used. Mucoperiosteal flaps were raised bilaterally at buccal and lingual aspects of the mandible to expose the angles. Next, 5 mm through-and-through bony defects were created bilaterally. On the test side, sterile medical grade prehardened calcium sulfate disks were applied both lingually and buccally to cover the defect. The control side defects were left uncovered. All flaps were sutured closed. Observation times were 3, 9, 18, and 22 weeks. RESULTS: Histologic analysis demonstrated that at 3 weeks all test sites showed partial or complete bone healing. Similar findings were reported for all observation times. The control group showed no bone growth at 3 and 9 weeks and partial bone healing at 18 and 22 weeks. CONCLUSIONS: This study indicates that calcium sulfate barriers can exclude connective tissues, allowing bone regeneration during healing.

Periodontal tissue regeneration in beagle dogs after laser therapy.

BACKGROUND AND OBJECTIVE: Class III periodontal furcations still represent a challenge for the periodontist. Aim of this study was to test the effect of CO2 laser on the treatment of class III furcation defects. STUDY DESIGN/MATERIALS AND METHOD: Class III furcation defects 3 mm deep were surgically induced on mandibular premolars on six male Beagle dogs, for a total of 36 defects. After 6-8 weeks of plaque accumulation, the mean depth was 6.8 mm. Quadrants were randomly assigned to a) CO2 laser therapy (laser), b) Guided Tissue Regeneration (GTR) procedure using Gore-Tex Membranes, (Gore Tex, Flagstaff, Arizona, USA) and c) Scaling and Root planing (Sc/Rp). CO2 laser beam (El.En, Florence, Italy) was applied to the root surfaces in defocused pulsed mode at 2W, 1 Hz and a duty cycle of 6%, and on periodontal soft tissues at 13W, 40 Hz, and a duty cycle of 40%. Control quadrants received either GTR procedure or Sc/Rp. Mechanical oral hygiene was provided. At 6 months the animals were sacrificed. RESULTS: The laser group showed new attachment formation averaging 1.9 mm (sd +/- 0.5), whereas GTR and Sc/Rp showed 0.2 mm (sd +/- 0.4) and 0.2 mm (sd +/- 0.5) respectively, being the differences statistically significant between the laser group and both GTR and Sc/Rp groups (p < 0.005). CONCLUSION: CO2 laser treatment of class III furcation induced formation of new periodontal ligament, cementum and bone.

Topographic distribution of subgingival plaque along root surfaces of human periodontally diseased teeth. A descriptive study.

The purpose of this study was to characterize the topographical distribution and organization of subgingival plaque in periodontally diseased teeth. 26 extracted teeth were fixed and processed for undecalcified histological evaluation. The sections were cut perpendicular to the long axis of the tooth and analyzed by phase-contrast microscopy. The coronal portion of the analyzed roots showed a dense accumulation of filamentous forms, fusiform rods, coccoid forms and loosely aggregated spirochetes. The middle and apical portions showed a non-uniform distribution of the microflora, with microorganisms representing all the known morphotypes. Furthermore, plaque was detected below undisturbed periodontal fibers, indicating that plaque not only forms apically, but also in a lateral direction, penetrating and colonizing below areas where periodontal fibers are inserted into the root surface.

A comparison of crossover versus parallel-group design in the evaluation of analgesic efficacy after molar extraction.

This study compares the analgesic effects of two standard combinations (Empirin with codeine versus Mersyndol) and placebo as measured by crossover versus parallel-group design. The analgesic results obtained with three groups of 12 to 13 crossed over subjects with two extractions divided into six subgroups of five to seven subjects for each sequence were qualitatively the same and statistically at least as strong as those obtained by analysis of parallel groups of 38 to 42 extractions per group. By both methods the analgesics were statistically significantly more effective than placebo. The difference between the two products was not statistically significant, although the score for Mersyndol was somewhat better by both methods of study. The crossover data did not allow judgments concerning side effects in spite of its greater efficiency in quantifying pain relief.

Bacteremia following laser and conventional surgery in hamsters.

The CO2 laser prevents bleeding by sealing blood and lymph vessels as it vaporizes tissue. Bacteremia following oral surgery might not occur under these conditions. To test this hypothesis, a 0.2-mm-deep incision 1 cm long was made in the right buccal cheek pouch of hamsters using either laser, electrosurgery, or a scalpel. Twenty minutes later, 1 mL of blood was taken from each animal by cardiac puncture, inoculated on a blood agar medium, and incubated anaerobically for 4 days; then the colonies were counted. Using an operational definition of bacteremia as five colonies or more per plate, there were no positive results out of 18 trials (0/18) for laser surgery, 7/8 for electrosurgery, and 8/12 for scalpel surgery. Based on the Student t test using the binomial distribution, the laser produced statistically less bacteremia than the other two methods (P less than .01). Because the five-colony cutoff was arbitrary, the nonparametric Wilcoxon Rank test was also used. Colony formation from blood from the laser group was significantly less than from the electrosurgery group (P less than .01) and the scalpel group (P less than .05). The laser surgery group was not statistically different from the control (nonsurgerized) group. These results suggest that there is a considerable bacteremia following scalpel and electrosurgery, but that laser surgery produces no bacteremia.

Lubrication and viscosity features of human saliva and commercially available saliva substitutes.

The lubricating features and viscosity of human saliva and five commercially available saliva substitutes were compared. The results indicate that little correlation exists between these parameters. Saliva substitutes based on carboxymethylcellulose do not appear to lubricate biocompatible hard interfaces well and, therefore, might not protect against the rapid attrition observed in xerostomic individuals. In contrast, a mucin-based substitute proved to be a better lubricant with values comparable to whole human saliva.

Artifacts in oral biopsy specimens.

More than proper surgical technique is required to facilitate the proper diagnosis of an oral biopsy specimen. The proper preparation of the tissue for microscopic analysis depends on steps taken by the surgeon, assistant, and histotechnician to reduce the inclusion of artifacts. There are many ways that the exact interpretation of tissue specimens can be compromised. Unfortunately, many practitioners seem to be unaware of the extent of this problem, as well as how easily artifacts can be prevented.

Primates as a teaching model for biopsy.

It is our intention to poll former participants in this elective to determine their experience in biopsy of oral tissues in practice. To date, student critiques of this elective course have been positive; participants have strongly suggested that we continue this method of instruction. The use of animals can be justified by the fact that experience gained in this course is applicable to the serious problem of early detection of oral cancer. Curricula that include biopsy procedures will produce dentists who will be comfortable using this important diagnostic method in their practices. Studies indicate that more general dentists are utilizing biopsy. It is important that this trend be encouraged, and the use of the nonhuman primate in a course such as that described above is a positive step in this direction.

The effects of alcohol and cetylpyridinium chloride on the buccal mucosa of the hamster.

The effects of alcohol and cetylpyridinium chloride on normal and abraded hamster buccal pouches were studied in 23 study and 23 control animals over 21 consecutive days. No significant differences were found between the control and study animals, both groups having normal cheek pouch mucosa at the end of the study period.

Lateral orbital rim fracture: an unusual case.

An unusual fracture of the facial skeleton has been described to show that an apparently simple injury to the lateral aspect of the orbit can lead to serious consequences. In this case, the consequence was progressive loss of vision, which possibly could have led to blindness. It is recommended that all diagnostic methods should be employed in assessing an injured patient. The patient's history, in conjunction with inspection, palpation, and clinical judgment and experience, will almost always lead to a diagnosis. Radiographic confirmation can then be obtained and special views employed when indicated. These methods must be used in the evaluation of even apparently simple injuries so that the patient can be properly treated.