Clinical and radiographic study of dens invaginatus.

After a determination of the frequency of dens invaginatus by means of radiographic observations, various problems of its identification are discussed. The 188 teeth showing a distinct loop-shaped invagination apically on the radiograph were studied for the presence or absence of caries and periapical lesions. It was demonstrated that periapical lesions caused by caries are mostly due to interproximal caries and that the frequency of periapical lesions caused by caries in the dens invaginatus area was less than previously reported. Comments are made on the dens invaginatus cases having periapical lesions without caries and the parameters for future studies.     

Clinical evaluation of a low-friction attachment device during canine retraction

OBJECTIVE: The present study used a split-mouth design to compare the amount of canine movement and the retraction time between brackets with Clear Snap and brackets with stainless steel ligature wires for three different levels of retraction force. MATERIALS AND METHODS: A sample of 30 patients was used. After initial leveling, the canine was retracted using a 50-g (n = 10), 100-g (n = 10), or 150-g (n = 10) closed-coil spring. The canine on one side was chosen at random, and Clear Snap was attached to the bracket during the retraction period. The other side was used as a control. The amount of canine retraction was measured with a digital vernier caliper. Statistical analysis was performed by analysis of variance. RESULTS: The average canine retraction time was approximately 2 to 3 months less in all experimental groups (50, 100, and 150 g) compared to the control group. In the control group, 150 g resulted in a shorter duration of canine retraction compared to 50 g. There was no significant difference in the duration of canine retraction among the experimental groups. A greater amount of mean total canine movement was observed in all experimental groups compared to the control groups. CONCLUSION: A shorter duration of canine retraction time was observed with Clear Snap attached when compared with the control. The authors suggest that with the use of Clear Snap, less than 50 g of force may effectively retract a canine.     

Haemostatic management of intraoral bleeding in patients with von Willebrand disease

OBJECTIVES: To develop plans for the haemostatic management of intraoral bleeding in patients with von Willebrand disease (VWD). SUBJECTS AND METHODS: Thirty-seven episodes of haemostatic management of intraoral bleeding in 19 VWD patients were analysed retrospectively based on the medical records. RESULTS AND CONCLUSIONS: When performing tooth extractions in patients with type 1 or 2A VWD [responsive to 1-deamino-8-D-arginine-vasopressin (DDAVP)], 0.35-0.4 microg kg(-1) of DDAVP should be administered intravenously at three times. In patients with type 2A VWD (unresponsive to DDAVP) or patients with type 2B or 2N VWD, 50-90 U [as ristocetin cofactor (VWF:RCof)] kg(-1) of a factor VIII concentrate containing von Willebrand factor (FVIII/VWF concentrate) should be administered twice in routine extractions, and four to six times in surgical extractions. Gingival bleeding related to primary teeth can be mostly managed by pressure haemostasis alone. However, when treating gingival bleeding caused by marginal periodontitis, it is often necessary to administer 0.4 microg kg(-1) of DDAVP or 40-70 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. As local haemostasis is difficult to achieve in bleeding from the tongue or labial or mandibular haematoma, it is necessary to administer 0.4 microg kg(-1) of DDAVP or 60-80 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. In addition, oral administration of 20 mg kg(-1) day(-1) of tranexamic acid should be combined with the regimens described above.     

Analysis of major components contained in Bis-GMA monomer

The major components contained in commercial Bis-GMA monomer were isolated by thin layer chromatography (TLC) and identified by NMR and high resolution mass spectroscopy. In addition to the two major components already known (Bis-GMA and Iso-bis-GMA), an unknown hydrophilic third major component was isolated and identified as 2,2-[4-(2-hydroxy-3- methacryloyloxy-1-propoxy)-4'-(2,3-dihydroxy-1-propoxy)]dipheny lpropane. This compound was designated as BIS-GMA-H, because it has a structure of Bis-GMA with one of which methacrylic ester bond hydrolyzed.     

Microvascular response in the periosteum following mucoperiosteal flap surgery in dogs: angiogenesis and bone resorption and formation

BACKGROUND: When surgical stress reaches the periosteum, bone resorption and formation that occur as a periosteal response are closely related to angiogenesis and hemodynamics. Thus, we investigated bone remodeling in the healing process after mucoperiosteal flap surgery, focusing our attention on the microcirculation. METHODS: Mucoperiosteal flap surgery was performed on 12 adult beagle dogs. The periosteal vascular plexus was observed on days 7, 14, 21, and 28 after surgery, using three different techniques: in histological specimens into which India ink was injected into blood vessels, under a light microscope; in ultrathin sections, using a transmission electron microscope; and in acryl plastic-injected vascular corrosion cast specimens, under a scanning electron microscope. RESULTS: On day 7 after surgery, the interstitum of the elevated mucoperiosteal vascular plexus was filled with sinusoidal new blood vessels. Bone resorption by osteoclasts was observed around these new blood vessels and many highly permeable fenestrations were present in the vascular endothelium. On day 14 after surgery, sinusoidal new blood vessels were more markedly developed and some regions exhibited glomeruluslike morphology consistent with bone resorption cavities. Activated osteoblasts were present around these new blood vessels and highly permeable vesicles, which were considered to be possible vesiclo-vacuolar organelles (VVOs) and caveolae, were noted in the vascular endothelium. On days 21 and 28 after surgery, the mucoperiosteal vascular plexus was dissected through regression of endothelial cells and fibroblasts and reconstructed into a rough mesh structure, and simultaneously the bone surface became smooth. CONCLUSION: The morphology of the mucoperiosteal vascular plexus changed with bone metabolism and these changes contributed to transport of substances involved in periodontal repair.     

Hydrogen sulfide causes apoptosis in human pulp stem cells

Introduction

Untreated dental caries will eventually lead to pulpal inflammation. Although much is known regarding the interaction of microbial antigens and the immunologic defense systems of pulp, many aspects of the pathogenesis of pulpitis are not fully understood. The relationship between human pulp stem cells (HPSCs) and the pathogenesis of pulpitis remains among the poorly understood areas. Many of the invading bacteria are known to produce considerable amounts of hydrogen sulfide (H₂S), which causes apoptosis in some tissues. The aims of this study were to determine whether H₂S causes apoptosis in HPSCs and to examine its signaling pathway.

Methods

Stem cells were isolated from human dental pulp and incubated with 50 ng/mL H₂S for 48 hours. To detect apoptosis, the cells were analyzed by using flow cytometry. The mitochondrial signaling pathway was examined by determining mitochondrial membrane depolarization. Activation of the key apoptotic enzymes caspase-9, caspase-8, and caspase-3 was assessed by using enzyme-linked immunosorbent assay. Release of cytochrome C from mitochondria was also determined.

Results

The number of apoptotic cells increased significantly with H₂S treatment from 1.6% to 16.3% (P < .01). Significant increases were also measured in the amounts of caspase-9 and caspase-3 and in cytochrome C release (all P < .01) and in mitochondrial membrane depolarization (P < .05), whereas caspase-8 activity was not found.

Conclusions

H₂S causes apoptosis in HPSCs by activating the mitochondrial pathway. It is suggested that H₂S might be one of the factors modifying the pathogenesis of pulpitis by causing loss of viability of HPSCs through apoptosis.     

Operative treatment of metacarpal and phalangeal fractures in athletes: early return to play

Background

Evaluating the outcomes of operative treatment for metacarpal and phalangeal fractures in athletes returning early to play and discussing the more effective methods that permit rapid early return to athletic activity.

Methods

We retrospectively identified a total of 105 metacarpal or phalangeal fractures in 105 athletes with conservative or operative treatment in our department. Of these, 20 athletes required an early return to sport because of a pending important game in their competition within 1 month after injury. Therefore, they underwent surgical treatment with open reduction and internal fixation of metacarpal or phalangeal fractures in an attempt to achieve an early return to their chosen sport at their usual competitive level. The patients included 6 rugby football players, 2 soccer goalkeepers, 3 American football players, 3 handball players, 2 baseball players and 4 who participated in other sports. The clinical records of preoperative and postoperative radiographs were available for all patients, and clinical outcome was evaluated by total active motion (TAM).

Results

The patients were followed up for a mean of 27 (24–43) months. At the latest follow-up examination, bone union was obtained in all cases. In cases with metacarpal and phalangeal fractures, the average TAM was 263° (range 240°–270°).

Conclusion

We consider that an early comeback to training and competition can be permitted exclusively for patients with metacarpal and phalangeal fractures. It is important for the attending physician to administer such treatment after obtaining informed consent and develop a trusting relationship with the patient and other related individuals while paying attention to their hope of quick recovery.