Does the control of alanine aminotransferase levels lead to a regression of liver fibrosis in chronic hepatitis C patients?

The aim of this study was to investigate the effect of various medications other than interferon (IFN) on liver fibrosis in chronic hepatitis C (CH-C) patients, and the results were compared with those obtained in CH-C patients without therapy. Fifty CH-C patients (32 men and 18 women; mean age 58.5 years) without previous IFN therapy, who randomly received medicines other than IFN such as Stronger Neo-Minophagen C, Ursodeoxycholic acid and a herbal medicine, Sho-saiko-to (TJ-9) (Group I), and as a control group, 45 CH-C patients (27 men and 18 women; mean age 56.6 years) without therapy (Group II) were examined. All patients had persistent alanine aminotransferase (ALT) elevation more than 6 months before this study and were also subdivided into three subgroups according to different pattern of ALT during the observation period, i.e. (a): persistently ALT<60 IU/l (below about twice the upper limit of normal range); (b): persistently ALT>/=60 IU/l; and (c) other than (a) and (b). All patients were biopsied twice before starting this study and during observation period and the liver fibrosis was compared between them by staging in each case. When the fibrosis stage was the same between two specimens, we determined whether the degree of fibrosis had improved or worsened by computed image analysis. Blood tests for fibrosis marker, serum aminoterminal peptide of type III procollagen (P III P) and liver enzyme such as albumin (Alb) and zinc turbidity test (ZTT) levels, and platelet (Plt) counts were also examined on the two times of liver biopsy. As a result, there were no significant differences in fibrotic improvement rate when assessed by both staging only and staging together with fibrotic ratio, determined by computed image analysis and also in yearly change of P III P (P/Y) and fibrosis (F/Y), the changed rate of Alb, ZTT levels and Plt counts between Group I and Group II, except for P/Y in subgroup (a) which was rather higher in Group I than in Group II. There were also no significant relationship between the changes of histological activity and fibrosis staging in both groups. In conclusion, other medications than IFN could not significantly improve both liver fibrosis and its associated laboratory data irrespective of ALT levels in CH-C patients as compared to the control group during average 3 years' follow-up period.

Influence of TT virus on the clinical course of alcoholic liver disease

The sera of 43 patients with alcoholic liver disease (ALD) who abstained from alcohol for 4 weeks, were tested for TT virus (TTV) DNA by polymerase chain reaction (PCR) using three different primer pairs (UTR PCR, N22 PCR and genotype-1 PCR). The clinical course of the TTV DNA-positive and -negative groups was compared. By UTR PCR which detects all TTV genotypes, TTV DNA was detected in 40 patients (93%). N22 PCR which detects primarily TTV genotypes 1-6, detected TTV DNA in 17 patients (40%). The alanine aminotransferase (ALT) level 4 weeks after the start of abstinence was significantly higher and the rate of change in ALT {[(ALT on admission-ALT 4 weeks after abstinence)/(ALT on admission)]x100} was lower in the patients who were positive by N22 PCR, than in those who were negative by N22 PCR. Twelve patients (28%) were positive for TTV genotype 1. In the TTV genotype 1-positive group, the ALT 4 weeks after the start of abstinence was significantly higher, and the improvement rates of ALT, gamma-glutamyl transpeptidase and alkaline phosphatase levels were lower than those in the TTV genotype 1-negative group. These results suggest that certain genotypes of TTV may interfere with the improvement of liver function following the start of abstinence in ALD patients.

Ynolate chemistry. Reaction of a silylynolate with aziridines leading to gamma-lactams

A silylynolate, generated via the carbonylation of lithium silyldiazomethane, was reacted with N-tosyl aziridines to produce various five-membered lactams in good yields. The key step of this reaction involves the ring-opening ketenylation of aziridines by the silylynolate. The reaction proceeded in a highly stereoselective manner, and ketenylation took place at the less hindered carbon. When treated with aldehydes prior to protonation, the alpha-silylated lactam enolates gave alpha-vinylidene gamma-lactams. These reactions represent a unique path to the generation of and for controlling the reactivity of a rare class of reactive intermediates, namely, acyllithium derivatives and ynolates.

In vivo changes in free choline level induced by autonomic agonists in mouse organs, including three major salivary glands

Whether free choline levels are changeable in vivo in response to different types of autonomic agonists was examined in several mouse organs. Upon one subcutaneous injection of isoproterenol, phenylephrine and pilocarpine, choline levels in whole organ decreased, increased and decreased, respectively, in various organs within 30 min and returned to initial levels in a day. In the three major salivary glands, a delayed choline elevation also appeared on day 2 after one isoproterenol injection and subsided by day 6. Only in the three salivary glands more choline was accumulated after 10 once-a-day injections of isoproterenol than after one isoproterenol injection. Neither phenylephrine nor pilocarpine induced comparable choline accumulation in any organs examined. Isoproterenol injection repeated at a 2-day interval augmented the subsequent, delayed choline elevation. Examination with dobutamine and the adenylyl cyclase activator 6-(3-dimethylaminopropionyl)forskolin suggested that isoproterenol-induced immediate choline lowering was down-stream of cAMP synthesis and linked to cAMP more tightly than the choline accumulation, though both choline changes occurred via beta1-adrenergic receptors. Choline levels in the salivary glands also changed depending on the form of diet given and particularly in the parotid gland in parallel with gland weights. These results provide the first evidence for the autonomic control of intracellular choline levels; intracellular choline levels might be an integral part of the autonomic signalling pathway.

Detection of mitochondrial DNA mutations in human gingival tissues

The accumulation of mitochondrial DNA mutation is an important contributor to the aging process. Polymerase chain reaction (PCR) amplification was carried out on total DNA from gingival tissues of human subjects with ages of 19 to 64 years, and 5.0-kb and 7.4-kb deletions were found in the mitochondrial genomes of these subjects. This is the first report of mitochondrial DNA deletion detectable in human gingival tissues.

Involvement of hrs binding protein in IgE receptor-triggered exocytosis in RBL-2H3 mast cells

Hrs binding protein (Hbp) tightly associated with Hrs is thought to play a regulatory role in vesicular trafficking during endocytosis and exocytosis. In this study, we have expressed dominant-negative mutants of Hbp to evaluate their effects on the degranulation of secretory granules in RBL-2H3 mast cells. The dominant-negative mutants of Hbp significantly inhibited IgE receptor (FcepsilonRI)-triggered secretory response as tested by beta-hexosaminidase release. These results suggest that Hbp functions as a regulator in the FcepsilonRI-triggered degranulation of secretory granules in mast cells.

Analysis of aspartate aminotransferase in gingival crevicular fluid assessed by using PocketWatch: a longitudinal study with initial therapy

AIM

The aim of this longitudinal study was to analyze the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) by using PocketWatch before and after initial therapy in patients with chronic adult periodontitis and to determine the relationship between AST and conventional measures of periodontal status, such as probing depth, clinical attachment level, bleeding on probing, and gingival index.

METHOD

A total of 11 patients with chronic adult periodontitis were enrolled. Their periodontal status and AST levels in GCF were measured at baseline and post-initial therapy (the number of pockets=67), and statistically analyzed.

RESULTS

There was a statistically significant difference in AST levels between diseased periodontal sites (1.2+/-0.7) and healthy sites (0.3+/-0.6, p<0.05), and between baseline and post-initial therapy (p<0.05). Improvements in clinical status were noted following periodontal therapy and there was a corresponding decrease in AST levels.

CONCLUSIONS

In conclusion, it is suggested that AST levels may be a useful adjunct in the clinical assessment of periodontal disease sites, since AST level decreases when periodontal status improves.

A comparison of the bactericidal effects and cytotoxic activity of three types of oxidizing water, prepared by electrolysis, as chemical dental plaque control agents

Acid oxidizing water (AOW), neutral oxidizing water (NtOW) and acid oxidizing water with a low available chlorine concentration (AOW-LC) may be obtained by electrolyzing a solution of tap water containing various quantities of NaCl and HCl. This study compared the bactericidal effects of these waters on cariogenic and periodontopathogenic bacteria and their cytotoxicities against epithelial cells. AOW, NtOW and AOW-LC showed considerable bactericidal effects. The cytotoxicity of AOW-LC was significantly lower than the other solutions tested (P<0.0001). The results indicated that the three types of oxidizing water had similar activity in inhibiting bacterial plaque formation as conventional chemical plaque-control agents.

A preliminary comparative study of the guided tissue regeneration and free gingival graft procedures for adjacent facial root coverage

OBJECTIVE

The purpose of this study was to compare the clinical efficacy of guided tissue regeneration with expanded polytetrafluoroethylene membranes to that of free gingival graft for treatment of adjacent facial gingival recession.

METHOD AND MATERIALS

Eight adjacent gingival recession sites with Miller class I or II defects containing at least a maxillary or mandibular canine were selected in 6 patients. Four recession sites in 3 patients were treated with guided tissue regeneration, and the other 4 sites in the remaining 3 patients were treated with free gingival graft. Probing depth, gingival recession, attachment level, width of keratinized gingiva, and root coverage were recorded before surgery (baseline) and 6 months and 1 year postoperatively.

RESULTS

Statistically significant improvements were found for gingival recession, attachment level, and root coverage from baseline to 6 months and 1 year postoperatively in both groups. Both procedures produced the same average reduction in gingival recession, gain in attachment level, and amount of root coverage after 1 year. Probing depths did not differ between groups throughout the study. The width of keratinized gingiva was significantly greater in the grafted group than in the guided tissue regeneration group.

CONCLUSION

Both procedures produced the same average amount of root coverage, reduction in gingival recession, and gain in clinical attachment. The guided tissue regeneration procedure provided a better esthetic appearance without any difference in gingival color or architecture in cases of adjacent facial gingival recession.

Changes of liver fibrosis in chronic hepatitis C patients with no response to interferon-alpha therapy: including quantitative assessment by a morphometric method

The aim of this study was to evaluate the antifibrotic effect of interferon (IFN)-alpha in chronic hepatitis C (CH-C) patients with no response to IFN-alpha therapy. We studied 76 patients (46 men, 30 women; mean age, 55.6 years) who received IFN-alpha intramuscularly, at a total close of 480 to 880MU for 6 months (group A). As a control group, we studied 50 patients (32 men and 18 women; mean age, 58.5 years) with CH-C who received medication other than IFN (ie, Strong-Neo-Minophagen C, ursodeoxycholic acid, and a herbal medicine, Sho-saiko-to [TJ-9]) and who had persistent alanine aminotransferase (ALT) elevation (group B). All patients were subdivided into three subgroups according to different patterns of ALT changes during the observation period, ie, (a) persistent ALT level < 60IU/ 1 (below about twice the upper limit of the normal range), (b) persistent ALT level > or = 60IU/1, (c) ALT levels other than (a) and (b). Liver biopsy was performed within 6 months prior to IFN therapy and more than 6 months after IFN therapy, while two liver biopsies were performed during therapy in group B. Liver fibrosis was compared between two specimens by staging. When the fibrosis stage was the same in the two specimens, we determined whether the fibrosis had improved or worsened by comparing the fibrotic ratio, ie, the ratio of the area of fibrosis to the area of the entire liver tissue specimen, calculated using computed graphic software. Serum aminoterminal peptide of type III procollagen (PIIIP) levels were measured on the day of the liver biopsy and their mean yearly changes were compared between the two groups. Improvement of liver fibrosis was found in 12% to 30% of patients in each ALT subgroup and in 24% of all patients in group A and there were no significant differences in liver fibrosis in comparison with findings in of group B when assessed by staging alone. However, these percentages rose to 59% to 75% and 66%, respectively, when liver fibrosis was assessed by the fibrotic ratio together with staging, resulting in a significant difference in fibrosis between groups A and B in total (P < 0.01). The mean yearly changes in serum PIIIP levels in each subgroup and in all patients in group A were below zero, indicating a tendency to improvement of fibrosis after IFN therapy, while these changes in group B were all above zero, except for subgroup (c). Improvement of fibrosis after IFN therapy was found in 15 of 24 patients (64%) whose ALT changes had the same pattern before and after IFN therapy, although no significant difference was noted between improved and worsened patients. These results suggest that IFN-alpha may have an antifibrotic effect even in CH-C patients with no overt response to IFN-alpha therapy, compared with the effect of medications other than IFN.

Improvement of multiple facial gingival recession by non-surgical and supportive periodontal therapy: a case report

We report a case of multiple facial gingival recession which was improved by non-surgical and supportive periodontal therapy. The patient, a 28-year-old Japanese woman, presented for treatment of multiple facial gingival recession ranging from 1 to 4 mm on teeth 5 through 12 and 19 through 30. Periodontal plastic surgery to cover the exposed multiple root surfaces was suggested. However, because of emotional problems, the patient did not wish to undergo the procedures and instead accepted non-surgical periodontal therapy including oral hygiene instruction, scaling, and root planing. The exposed root sites were monitored at periodic maintenance visits, and gradual improvement through a coronal increase of the gingival margin was noted. The possible etiologic factors and healing process associated with this case are discussed.

Osseointegration around titanium screws placed into the areas between guided bone augmented sites compared with osseointegration around guided bone graft augmented sites in rabbit tibia

The aim of this study was to compare the degree of osseointegration around titanium screws placed into the areas between guided bone augmented sites and guided bone graft augmented sites in 8 Japanese white rabbit tibia. The skin and periosteum were incised and lifted to expose the inner surfaces of both tibia. Eight rabbits were divided into 2 groups: 1) a guided bone augmentation (GBA) group of 2 rabbits, and 2) a guided bone graft augmentation (GBCA) group of 6 rabbits. In the GBA group, the bone marrow was penetrated several times in both tibial bones. Three titanium screws were inserted into the bone so that the top of each screw was 3 mm above the bone surface and covered with an expanded polytetrafluoroethylene membrane (ePTFE). In the GBGA group autogenous cortical bone (10 mm x 10 mm x 1 mm) was taken from the left tibia and grafted on the inner surface of the right tibial bone, titanium screws being similarly inserted. The surgical site was covered by ePTFE. After healing for 2 months, the animals were euthanatized, and the experimental area was prepared for histological investigation. New bone had formed on the surgical sites in the GBA group and grafted bone had survived in the GBGA group, with no sign of infection or membrane exposure. The degree of osseointegration around the screw was 67.6 +/- 11.2% (mean +/- SD) in the GBA group and 78.8 +/- 11.9% in the GBGA group. There was no significant difference between the groups (p = 0.29). The ratio of mineralized bone to bone marrow was 45.7 +/- 6.2% in the GBA group and 64.4 +/- 4.4% in the GBGA group. There was a significant difference between the groups (p < 0.05). Although there was no significant difference for osseointegration around the screw placed into the GBA and GBGA sites, the quality of newly generated bone or grafted bone was quite different. Therefore, we suggest that predictable bone augmentation beyond the bone surface can be achieved by either the GBA or the GBGA procedure with ePTFE. However, it was difficult to conclude which procedure was superior with respect to the osseointegration around the titanium screw.

Cyclosporin A inhibits H2O2-induced apoptosis of human fibroblasts

Several clinical studies have shown that cyclosporin A (CsA) is effective for treating a variety of chronic inflammatory and autoimmune diseases. Because reactive oxygen species are believed to play a key role in the development of these diseases, causing cell apoptosis, we investigated whether CsA inhibits H2O2-induced apoptosis. Preincubation of human fibroblasts with CsA dose-dependently decreased H2O2-induced apoptosis. Apoptosis suppression by CsA was correlated with the prevention of mitochondrial dysfunction and caspase activation. Thus, our results suggest that the inhibition of apoptosis by CsA may at least partly contribute to the anti-inflammatory effect of CsA.

Interferon treatment in patients with chronic hepatitis C with normal alanine-aminotransferase activity

BACKGROUND/AIMS

Chronic hepatitis C virus carriers may have repeatedly normal alanine aminotransferase activity despite detectable viremia and histological hepatitis. We aimed to evaluate the effect of interferon treatment in these cases.

METHODOLOGY

Twelve patients with persistently normal alanine aminotransferase levels at least 6 months before therapy were treated with recombinant interferon (IFN)alpha-2b for 6 months, totaling 840 MU in amount. Alanine aminotransferase levels were measured monthly during treatment and after treatment withdrawal, and HCV-RNA levels were measured by polymerase chain reaction before treatment, and 6 and 12 months after treatment withdrawal.

RESULTS

At treatment withdrawal, HCV-RNA levels had significantly decreased and HCV-RNA disappeared in 9 of the 12 patients by polymerase chain reaction. At 6 months after treatment withdrawal, HCV-RNA reappeared in 6 of the 9 patients whose HCV-RNA was negative at treatment withdrawal. Over all, only 4 of the 12 patients (33%) were sustained virological responders (HCV-RNA is negative more than 6 months after treatment withdrawal). Pre-treatment HCV-RNA levels in a sustained virological responder was significantly lower than that of transient and non-responders (4.9 +/- 1.6 vs. 7.7 +/- 1.6 log10[copies/ml], p < 0.05). Of 8 patients who did not achieved sustained virological response, alanine aminotransferase levels had transiently increased above normal during treatment in one patient and after treatment withdrawal in 6 patients; however, in the remaining one patient abnormal values have continued from 8 months after treatment withdrawal till now for 24 months.

CONCLUSIONS

In patients with chronic hepatitis C with normal alanine aminotransferase levels, the response to interferon therapy was by no means satisfactory. However, if it would be used in cases with the lower pre-treatment HCV-RNA levels with careful attention to a transient alanine aminotransferase elevation, the more a sustained virological response might be expected.

Relationship between levels of aspartate aminotransferase in gingival crevicular fluid and conventional measures of periodontal status assessed using PocketWatch: a cross-sectional study

The aim of this cross-sectional study was to determine, using PocketWatch, the relationship between the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) and conventional measures of periodontal status, such as probing depth, attachment level, bleeding on probing and gingival index, in patients with untreated chronic periodontitis. A total of 15 patients with chronic periodontitis were enrolled. Their periodontal status and AST levels in their GCF were measured (n = 93) and statistically analyzed. There was a statistically significant difference in AST levels between diseased periodontal sites and healthy sites (p < 0.0001). The coefficients of correlation between AST levels and probing depth, attachment level and gingival index at all sites were 0.436, 0.266 and 0.468 (Spearman rank correlation). The correlation coefficients were too small to show a definite relationship between AST levels and individual measures of clinical periodontal status. However, AST levels may help to confirm clinical observations in patients with chronic periodontitis before therapy, since AST levels differentiate active and inactive periodontal diseased sites.

Effects of experimental osteoporosis on alveolar bone loss in rats

A study was conducted to investigate the relationship between osteoporosis and alveolar bone loss. Alveolar bone loss was evaluated by radiographic and visual inspection of rats with experimental osteoporosis. Twenty 4-week-old female Sprague-Dawley rats were divided into the following groups: Group A-ovariectomized and given a standard solid diet; Group B-ovariectomized and given a calcium-deficient diet; Group C-sham-ovariectomized and given a standard solid diet; and Group D-sham-ovariectomized and given a calcium-deficient diet. After 4 weeks, the rat were euthanatized. The maxillae, mandibles, femurs, and tibias were removed carefully and fixed in 10% neutral buffered formalin. The bone mineral density of each bone and the alveolar bone loss were measured. The bone mineral densities of the maxillae, mandibles, femurs and tibias in Group C were significantly higher than those in Groups B and D, but not higher than those in Group A. However, there were no significant differences between any of the groups with regard to alveolar bone loss from the cemento-enamel junction to the molar bone crest. Therefore, it was concluded that osteoporosis itself may not be capable of causing periodontal destruction, and thus may not be a major factor in periodontal disease.

[Diagnosis and treatment of pulmonary tuberculosis complicated with chronic liver disease]

Immunocompromised or malnutritional hosts are high risk group of pulmonary tuberculosis. Chronic liver disease especially decompensated cirrhosis of the liver is one of the risk group for this infection. When ascites or pleural effusion developed in patient with hepatic cirrhosis, complication of pulmonary tuberculosis must be considered. In such condition, drug metabolism was impaired so that anti-tuberculous drugs should be used carefully, but in almost cases except decompensated cirrhotic patients are tolerable for standard anti-tuberculous combination therapy and they could be cured. Hepatitis C virus infection is common in patients with old pulmonary tuberculosis because many of them were infected Hepatitis C virus at the time of blood transfusion for pulmonary resection or thoracoplasty. In such condition recurrence of pulmonary tuberculosis is rare but probability of recurrence must be considered when they developed decompensated cirrhosis.

Nicotine inhibits the production of inflammatory mediators in U937 cells through modulation of nuclear factor-kappaB activation

Cigarette smoke is a major risk factor for lung cancer and respiratory infections. This increased susceptibility may result from cigarette smoke-induced impairment of the immune system. In this study, we evaluated the effect of nicotine on the production of inflammatory mediators by activated macrophages. Pretreatment with nicotine caused a significant inhibition of LPS-induced IL-1, IL-8, and PGE2 expression at the transcriptional level in U937 cells. Nicotine inhibited the activation of a transcription factor, NF-kappaB, which in turn, binds to and mediates transcriptional activation of these genes. These inhibitory effects of nicotine may contribute to cigarette smoke-induced immunosuppression.

Cyclosporin A inhibits collagenase gene expression via AP-1 and JNK suppression in human gingival fibroblasts

A frequent side effect of cyclosporin A (CsA) administration is gingival overgrowth. Although the molecular mechanisms of CsA-induced gingival overgrowth are still unknown, it has been postulated that CsA acts on lipopolysaccharide (LPS) to induce fibroblastic activity, which results in an increase of the extracellular matrix. Here we provide evidence that CsA is able to affect signal transduction of LPS-induced collagenase expression in fibroblasts. Treatment of fibroblasts with LPS caused activation of collagenase gene, activator protein-1 (AP-1) and c-Jun N-terminal kinase (JNK). These activations were blocked by CsA. We suggest that inhibitory effects of CsA on LPS-induced signal transduction may contribute to the mechanism of CsA-induced gingival overgrowth.

Effects of bioabsorbable and non-resorbable barrier membranes on bone augmentation in rabbit calvaria

The aim of this study was to compare the effects of bioabsorbable and non-resorbable membranes on experimental guided bone augmentation in 8 Japanese white rabbits. A cutaneous flap was demarcated and raised from the forehead of each animal, the periosteum was lifted, and the calvarial bone on both sides of the midline was exposed. A titanium screw was inserted into the bone on each side of the midline and one screw was covered with a bioabsorbable (polylactic acid) membrane and the other with a non-resorbable (expanded polytetrafluoroethylene) membrane. The implanted screws and membranes were then covered with the periosteum and cutaneous flap. After healing for 6 months, the animals were euthanized and the experimental area was prepared for histological investigation. New bone had formed under both membranes with no sign of infection or membrane exposure. The amount of newly generated bone (89.0 +/- 17.3% versus 54.7 +/- 14.0%, P <0.05) and the percentage of newly generated bone height (81.5 +/- 6.3% versus 58.9 +/- 7.8%, P <0.05) in the space beneath the non-resorbable membrane was greater than that beneath the bioabsorbable membrane. However, there were no statistically significant differences between the bioabsorbable and non-resorbable membranes with respect to the percentage areas of mineralized bone (52.3 +/- 11.3% versus 47.1 +/- 6.7%, P = 0.8658) and bone marrow (47.7 +/- 11.3% versus 52.9 +/- 6.7%, P = 0.4838) and bone contact with the screw (88.3 +/- 6.9% versus 89.2 +/- 7.3%, P = 0.9999). In conclusion, at least within the limitations of this rabbit model, we suggest that non-resorbable membranes with sufficient stiffness should be used to obtain greater bone volume and height instead of bioabsorbable membranes for the GBR procedure, and that this will facilitate predictable bone augmentation in spaces beyond the bone surface. Therefore, the bioabsorbable membrane could not replace the non-resorbable membrane used in this model.

The inhibitory effect of funoran and eucalyptus extract-containing chewing gum on plaque formation

The purpose of this study was to evaluate the inhibitory effect of funoran containing chewing gum (FG) and eucalyptus extract- containing chewing gum (EG) on plaque formation. Fifteen dentists or dental students were assigned a random order of use of either FG, EG or a control gum. All subjects received professional tooth cleanings before the experiment. During the four-day test periods, no oral hygiene measures were allowed other than chewing three pieces of gum for approximately 10 min daily. Chewing gum was used following each morning, noon and evening meal. Plaque formation was evaluated by the Quigley and Hein index. The FG (1.83 +/- 1.1) and EG (1.97 +/- 1.1) significantly reduced plaque compared to the control gum (2.57 +/- 1.2). Our results suggest that FG and EG may be useful in inhibiting dental plaque formation.

Incomplete fractures in intact bilateral maxillary first molars: a case report

A case of incomplete fractures occurring bilaterally in intact maxillary first molars is described. The etiology, diagnosis, and treatment of incomplete tooth fractures are discussed. The clinical results in this case showed that early diagnosis and treatment can prevent further extension of the crack into the pulp and subsequent complete tooth fracture.

Comparison of osseointegration between hydroxyapatite-coated and uncoated threaded titanium dental implants placed into surgically-created bone defect in rabbit tibia

The purpose of this study was to compare the degree of osseointegration between hydroxyapatite (HA)-coated and uncoated threaded titanium dental implants placed into a surgically created bone defect with or without an expanded polytetrafluorethylene (ePTFE) membrane. A conventional implant site was prepared and either a HA-coated or an uncoated implant was placed in each tibia of 12 rabbits (conventional group). A bone defect approximately 3 mm in width was created on the distal end of the conventional site and either a HA-coated or an uncoated implant was placed there (bone defect group). For another group, the same procedure was performed as in the bone defect group, except the implant sites were covered with ePTFE membranes (ePTFE group). After 4 months, the rabbits were sacrificed. Specimens were prepared and examined histometrically. The results demonstrated that HA-coated threaded titanium dental implants consistently showed a greater amount of osseointegrated surface either in the conventional site or defect region with and without ePTFE membranes in this animal model. In conclusion, a HA-coated threaded titanium implant may be the choice of dental implants to establish greater osseointegration with the defect or conventional site.