Cheng-Yang Chiang

Three‐dimensional analysis of the root morphology of mandibular first molars with distolingual roots

AIM To determine the prevalence of distolingual roots in mandibular first molar teeth in Taiwanese Han Chinese, and its impact on root morphology. METHODOLOGY The presence of distolingual roots in 375 subjects (521 molars) were assessed from 624 patients attending the dental clinics of medical centres around Taiwan island from August 2004 to April 2007 using computed tomography. The following observations were made: (i) numbers of roots and canals, (ii) mesial and distal root types and (iii) levels of furca in the molars presence or absence of distolingual root. RESULTS The mean age of the subject was 45; 43% were women. Among all the examined molars, 56%, 27% and 18% were two-, three- and four-rooted, respectively. Two per cent, 72% and 26% of molars had two, three and four canals, respectively. All of the four-rooted molars had four canals, but all of the molars with four canals varied in the number of roots. All molars with distolingual roots had two mesial canals. Bilateral consistency in terms of distolingual root, root canal number, root number and root type was observed in subjects with bilateral molars. In molars with distolingual roots, a higher prevalence of two mesial roots and a shorter mesial root trunk were observed than in teeth without distolingual roots. CONCLUSIONS A distolingual root was found in 22% of molars and in 24% of the subjects examined. Most subjects with a distolingual root had them bilaterally. The presence of a distolingual root was associated with variation in the root morphology, including the furcation level, the root type and the number of roots and canals.

Bifid mandibular canals and the factors associated with their presence: a medical computed tomography evaluation in a Taiwanese population

OBJECTIVES To examine distribution of bifid mandibular canals in a Taiwanese population and to evaluate factors contributing to the phenomenon. MATERIAL AND METHODS Computed tomographic images from 173 subjects (97 females and 76 males) were obtained using a 64-slice multidetector computerized tomography system, and the presence of bifid mandibular canals, as well as their widths and lengths, was examined. Association of length of bifid canals with possible contributing factors, including gender, age, and side of presentation, as well as size of cross-sectional bony area of mandible along the long axis of mandibular canal, was evaluated. RESULTS Bifid mandibular canals, with mean values of 10.1 and 0.9 mm in length and width, were found in 53 (30.6%) of 173 patients and 64 (18.5%) of 346 hemi-mandibles. Bifid canals appeared more frequently and tend to penetrate mandible with greater lengths in males if compared with those in females. When males were compared with females and when mandibles with bifid canals were compared with ones without, the former tend to present with larger bony area at corresponding levels of cross-sectional plane than the later, respectively. By regression analysis, significant association was found between length of bifid canals and gender, side of hemi-mandible, and bony area at mid-zone of mandibular canal. CONCLUSIONS Bifid canals were observed in 30.6% of subjects and 18.5% of hemi-mandibles. Significant association between length of bifid canals and gender, side of hemi-mandible, and cross-sectional bony area of mandible was observed.

Prevalence and location of maxillary sinus septa in the Taiwanese population and relationship to the absence of molars

OBJECTIVES Understanding the septum structure of the sinus is necessary for correct implant placement in the maxilla if sinus encroachment is required. The exact mechanism that controls septum development is unclear, although a role for the irregular pneumatization of the sinus floor following tooth loss has been suggested. The aims of this study were to examine the prevalence and location of sinus septa in the Taiwanese population and to determine whether there is a relationship between the presence of septa and the absence of molars. MATERIALS AND METHODS Using computed tomography (CT) scans of sinuses obtained from 423 subjects (216 women and 207 men, mean age 53.65 years), septum morphology and its correlation with the presence of molars was examined. RESULTS About 30% of subjects (124/423) had sinus septa, corresponding to 20.45% of all sinus segments detected (173/846). Fifty-nine patients had multiple septa, giving a prevalence of septa of 22.93%. Septa were located most frequently in the regions of the first and second molars. The prevalence was not related to tooth loss (edentulous, partially edentulous, or dentate maxillary segments). Logistic regression analysis showed that men were significantly more likely to have septa than were women (OR=1.67; P=0.019). CONCLUSIONS In the 423 Taiwanese subjects tested, the prevalence of septum was 29.31% according to the subjects and 22.93% according to the sinus segments. The most frequent location of septa was in the region of the first and secondary molars. No correlation was observed between the presence of septa and the absence of molars.

Epigallocatechin-3-Gallate Attenuates Porphyromonas gingivalis Lipopolysaccharide-Enhanced Matrix Metalloproteinase-1 Production Through Inhibition of Interleukin-6 in Gingival Fibroblasts

BACKGROUND Recent studies have shown that epigallocatechin-3-gallate (EGCG), a major constituent of green tea extract, exhibits effects of anti-inflammation and antioxidation on periodontal inflammation. The present in vitro study examines the effect of EGCG on Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS)-enhanced expression of interleukin (IL)-6 and matrix metalloproteinase (MMP)-1, as well as the activation of nuclear factor-kappa B (NF-κB). Furthermore, the role of IL-6 on LPS-enhanced MMP-1 production is evaluated using human gingival fibroblasts (HGFs). METHODS HGFs were primary cultured from human gingiva specimens. The cytotoxicities of EGCG and LPS were tested by cell viability tests. The cellular mRNA expression of IL-6 was determined by reverse-transcription polymerase chain reaction, and the protein expression of MMP-1 and IL-6 was examined by enzyme-linked immunosorbent assay. The cytosol expression and nuclear translocation of NF-κB was evaluated by immunocytochemistry followed by confocal laser scanning microscopy. RESULTS Pg LPS significantly increased MMP-1 production in HGFs, whereas adding EGCG significantly attenuated this enhanced production of MMP-1. LPS treatment also increased the mRNA and protein expression of IL-6 and stimulated NF-κB activation in HGFs. However, the addition of EGCG significantly attenuated the IL-6 expression and NF-κB activation. Supplemental addition of IL-6 significantly enhanced cellular MMP-1 production, whereas anti-IL-6 antibody inhibited LPS-enhanced MMP-1 production. CONCLUSION EGCG could attenuate Pg LPS-enhanced production of MMP-1 in HGFs, whereas this attenuation might be due to the inhibition of IL-6 by EGCG.

Berberine's effect on periodontal tissue degradation by matrix metalloproteinases: an in vitro and in vivo experiment.

Periodontal disease involves tissue destruction caused by interactions among bacterial antigens and inflammatory mediators including matrix metalloproteinases (MMPs). Berberine, an isoquinoline alkaloid isolated from medicinal herbs, can inhibit the degradative action of extracellular MMPs. The effect of berberine on the periodontal expression of MMPs was examined in vitro and in vivo. Gelatinolytic activity of pro-MMP-2, MMP-2, and MMP-9 in the human gingival fibroblast and/or U-937 was compared after treatment with Porphyromonas gingivalis lipopolysaccharide (P.g. LPS) in four medias containing 0, 1, 10 and 100μM of berberine each. Twelve animals were divided into three groups for the study: (A) non-ligation, (B) ligation, and (C) ligation-plus-berberine (75mg/kg berberine by gastric lavage daily); and the effect of berberine on periodontal destruction was evaluated in the ligature-induced periodontitis in rats for 8 days by micro computerized tomography (micro-CT), histology and immunohistochemistry (IHC). An enhancing effect of P.g. LPS on MMP activities was identified, with a greater effect on fibroblasts/U937 co-culture than on either culture alone. When berberine was added to the LPS-treated cultures, the activities of MMPs were significantly reduced in dose-dependent manner. In the animals, the trends of the following parameters were compared. 1. Micro-CT distances between cemento-enamel junction (CEJ) and dental alveolar bone crest: B>C>A. 2. Histometrically measured crest bone levels: B>C>A. 3. Amount of collagen deposited in tissue areas: A>C>B. 4. Attachment loss: B>C≈A. 5. Connective tissue (CT) attachment: B>either A or C. 6. Expression of cells stained positive for MMP-2 and -9 by IHC: B>C>A. In conclusion, berberine demonstrated in vitro an inhibitory effect on P.g. LPS-enhanced MMP activities of HGF and U937 macrophages, reducing in vivo gingival tissue degradation in periodontitic rats. We thus propose that berberine may slow periodontal degradation through the regulation of MMPs in periodontitis induced by bacterial plaque.

Association of CCL5 and CCR5 Gene Polymorphisms With Periodontitis in Taiwanese

BACKGROUND It has been suggested that genetic factors may predispose individuals to periodontal diseases. The present case-control study aims to test whether the -403 single nucleotide polymorphism of chemokine ligand 5 (CCL5-403) and the 32-bp deletion of CCR5 (CCR5Δ32) polymorphisms are associated with susceptibility to chronic and aggressive periodontitis. METHODS Taiwanese participants (N = 213) were grouped into control group (CG), generalized aggressive periodontitis (GAgP), or chronic periodontitis (CP) groups. DNA samples were obtained from peripheral blood. CCL5-403, evaluated by polymerase chain reaction-restriction fragment length polymorphism, and CCR5Δ32, evaluated by polymerase chain reaction, were compared among the three groups. RESULTS There was a significant association between type of periodontitis and having allele A or G in the CCL5-403 polymorphism. GAgP patients were 3.7 times more likely than CP patients and 2.0 times more likely than CG patients to have allele A, instead of allele G, in CCL5-403. GAgP patients were 3.1 times more likely than CG patients to have AG versus GG genotype. GAgP patients were also 5.0 and 19.8 times more likely than CP patients to have AG and AA genotypes, respectively, compared to GG. For the CCR5Δ32 polymorphism, no association was found between the type of periodontitis and having different genotype or allele distributions among GAgP, CP, or CG patients. CONCLUSION The single nucleotide polymorphism of CCL5-403 G substitution by A may play a role in AgP; however, the CCR5Δ32 polymorphism may not.

Gelatinases and Extracellular Matrix Metalloproteinase Inducer Are Associated With Cyclosporin-A-Induced Attenuation of Periodontal Degradation in Rats

BACKGROUND The present study aims to examine the inhibitory effect of cyclosporin-A (CsA) on periodontal breakdown and to further explore the correlations of CsA-induced attenuation of periodontal bone loss with the expressions of gelatinases (i.e., matrix metalloproteinase [MMP]-2 and MMP-9) and extracellular matrix metalloproteinase inducer (EMMPRIN). METHODS Forty Sprague-Dawley rats were randomly divided into four groups: 1) control; 2) CsA; 3) ligature (Lig); and 4) ligature plus CsA (Lig + CsA). The CsA group received 10 mg ⋅ Kg(-1) ⋅ d(-1) CsA for 8 days. The Lig group received silk ligature on selected molars. The Lig + CsA group received silk ligature and CsA treatment. The inhibitory effects of CsA on the ligature-induced periodontal breakdown was examined with microcomputed tomography (micro-CT) and histometric analyses to analyze the amount of attachment loss, crestal bone loss, connective tissue attachment, and the surface area with inflammatory cell infiltration. The effects of CsA on ligature-induced expressions of gelatinases and EMMPRIN in gingival tissues were examined with Western blotting and zymography, respectively. RESULTS By micro-CT and histology, the Lig + CsA group had significantly more periodontal breakdown than the control and CsA groups but less periodontal breakdown than the Lig group. Consistent results were found for the expressions of gelatinases and EMMPRIN among the groups demonstrating that the Lig + CsA group had significantly less gingival protein expression of gelatinases and EMMPRIN than the Lig group. CONCLUSIONS CsA inhibited the expressions of gelatinase MMPs and EMMPRIN and partially prevented the periodontal breakdown in ligature-induced experimental periodontitis. The CsA-induced attenuation of periodontal bone loss was strongly correlated positively with the expressions of MMP-2, MMP-9, and EMMPRIN in gingiva.

Role of Shh and TGF in cyclosporine-enhanced expression of collagen and α-SMA by gingival fibroblast.

OBJECTIVE Cyclosporine-A (CsA)-induced gingival overgrowth may arise from an alteration in stoma matrix homeostasis. Sonic hedgehog (Shh) plays a key role during embryogenic development and fibrotic progression, and may be involved in CsA-altered gingival matrix homeostasis. METHODS Using the reverse transcription-polymerase chain reaction and Western blot analysis, we investigated the mRNA and protein expressions of Shh, type 1 collagen (COL1), alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-β) in human gingival fibroblasts after CsA treatments. The effect of Shh on CsA-induced alterations was further evaluated by the extra-supplement or inhibition of Shh or TGF-β. RESULTS Cyclosporine-A enhanced COL1, α-SMA, Shh and TGF-β expressions in human gingival fibroblasts. The exogenous Shh/TGF-β augmented the expression of COL1 and α-SMA, and the Shh/TGF-β inhibition suppressed the CsA-enhanced COL1 and α-SMA expressions. Moreover, Shh mRNA and protein expressions increased if extra-supplementing the exogenous TGF-β, whereas the CsA-upregulated Shh was mitigated by the TGF-β pathway inhibitor. However, neither exogenous Shh nor the Shh pathway inhibitor alters TGF-β expression or CsA-up-regulated TGF-β expression. CONCLUSIONS Shh, regulated by TGF-β, mediates CsA-altered gingival matrix homeostasis.

Effects of Salvia miltiorrhiza ethanolic extract on lipopolysaccharide-induced dental alveolar bone resorption in rats

Background/purpose Salvia miltiorrhiza (SM) Bunge (Labiatae/Lamiaceae; common name danshen) is a Chinese medicine that improves blood circulation and inhibits inflammatory response. Thus, it is used for the treatment of cardiac diseases and inflammation. In this study, we aimed to evaluate the effect of an ethanolic extract of SM (SME) on the dental alveolar bone resorption induced by bacterial lipopolysaccharide (LPS) in rats. Materials and methods An ethanolic extract was prepared from roots of SM. The major constituents of this extract were determined by high-performance liquid chromatography. The activity of the extract was evaluated in a rat model in which the dental alveolar bone resorption was induced by injection of bacterial LPS into the palatal gingiva around the maxillary molar teeth. The effect of SME on the bone resorption was studied by histologic and histomorphometric analysis. Results The number of osteoclasts and the percentage of osteoclasts covering the alveolar bone surfaces were significantly increased in the LPS group compared with those in the phosphate-buffered saline (PBS) group. The number and percentage of the osteoclasts on the bony surfaces were significantly reduced in the SME group in comparison with the LPS group, although it was still higher than the numbers observed in the PBS group. Conclusion Because SME reduced bone resorption caused by the injections of bacterial LPS in rats, we suggest that SME might have a protective effect on dental alveolar bone resorption in periodontitis.

Role of Transforming Growth Factor-beta1 in Cyclosporine-Induced Epithelial-to-Mesenchymal Transition in Gingival Epithelium

BACKGROUND It has been proposed that cyclosporin A (CsA) may induce epithelial-to-mesenchymal transition (EMT) in gingiva. The aims of the present study are to confirm the notion that EMT occurs in human gingival epithelial (hGE) cells after CsA treatment and to investigate the role of transforming growth factor beta1 (TGF-β1) on this CsA-induced EMT. METHODS The effects of CsA, with and without TGF-β1 inhibitor, on the morphologic changes of primary culture of hGE cells were examined in vitro. The changes of protein and messenger RNA (mRNA) expressions of two EMT markers (E-cadherin and alpha-smooth muscle actin) in the hGE cells after CsA treatment with and without TGF-β1 inhibitor were evaluated with immunocytochemistry and real-time polymerase chain reaction. RESULTS The epithelial cells became spindle-like, elongated, and disassociated from neighboring cells and lost their original cobblestone monolayer pattern when CsA was added. However, the epithelial cells stayed in their original cobblestone morphology with treatment of TGF-β1 inhibitor on top of the CsA treatment. When CsA was given, the protein and mRNA expressions of E-cadherin and α-SMA were significantly altered, and these alterations were significantly reversed with pretreatment of TGF-β1 inhibitor. CONCLUSIONS CsA could induce Type 2 EMT in gingiva by changing the morphology of epithelial cells and altering the EMT markers/effectors. The CsA-induced gingival EMT is dependent or at least partially dependent on TGF-β1.