Effects of circadian rhythm on the development of dental hard tissues / 中华口腔医学杂志

Circadian rhythm is regulated by circadian clock, which is formed by the body response to external cyclic stimuli through the endogenous circadian clock. Circadian rhythm disturbance is closely related to the risks of a variety of diseases, and its impact on oral health cannot be ignored. Exploring the relationship and related molecular mechanism between circadian rhythm and dental hard tissues development are helpful to deeply understand the pathogenesis of developmental defects on these tissues, which could provide a theoretical basis for prevention and treatment on disorders of dental hard tissues. In order to provide guidance for the disease prevention and treatment, based on the summarization of current research progress, this paper focuses on the involvement of biorhythm in the development of tooth hard tissues as well as the disturbance of circadian rhythm on the formation of enamel and dentin, and analyzes the related regulating mechanism of circadian rhythm and genes during the development of tooth hard tissues.

An in vitro model study of computer-guided endodontic microsurgery / 中华口腔医学杂志

Objective: To assess and compare the accuracies and operating time of endodontic microsurgery performed by operators with different levels of experience in endodontics using computer-guided techniques including dynamic and static navigations in a surgical simulation model. Methods: Six pairs of three dimensional (3D)-printed models of upper and lower jaws were set up on dental manikins. A total of 120 teeth (10 teeth each jaw) were included in the models. Microsurgeries of osteotomy and root-resection were performed on the models by two operators with different experience, namely novices and experts, under of free hand (FH)(n=20), dynamic navigation (DN)(n=20), and static navigation (SN)(n=20) conditions, respectively. The duration of each operation was recorded. Cone-beam CT was taken for 3D-printed models before and after the operation. The path of preoperative surgery planning was simulated. The linear deviations at the entry and the end point and the angular deviation of the access path between the simulated and the actual operation were compared by the software. Results: Significant difference of the entry deviation was observed between the novices and the experts in the FH group [(1.44±0.49) and (1.02±0.58) mm] (q=4.67, P=0.020). There were no significant differences between the novices and the experts in the end point and angular deviations (P>0.05). For the novices, the entry deviations in both DN and SN groups [(0.76±0.32) and (0.66±0.20) mm] were significantly lower than those in FH group (q=7.58, P<0.001; q=8.66, P<0.001). The angular deviations in the abovementioned two groups (5.0°±3.5°, 3.9°±2.1°) were significantly lower than that in FH group (10.9°±6.1°) (q=7.38, P<0.001; q=8.70, P<0.001). For the experts, significant differences were found only in the angular deviations among DN, SN and FH groups (3.6°±1.9°, 3.2°±1.7° and 8.2°±3.9°) (q=5.74, P=0.001; q=6.29, P<0.001). The operation durations were significantly shortened for both the novices [(4.80±2.15), (1.09±0.48) min] (q=14.60, P<0.001; q=20.10, P<0.001) and the experts [(3.40±1.96),(1.02±0.34) min] (q=5.86, P<0.001; q=9.37, P<0.001) by using DN and SN techniques. Regarding the differences between tooth types, in FH group, the operating time on the anterior teeth was significantly shorter than that on the posterior teeth (q=8.14, P<0.001; q=5.20, P=0.007), while in DN and SN groups, there were no significant differences in the operating time between two tooth types (P>0.05). No significant differences were discovered in the accuracies on the anterior and posterior teeth among three techniques or between two kinds of operators (P>0.05). Conclusions: Dynamic and static navigation techniques could assist the clinicians, especially the novices, to improve the accuracies and shorten the operating time of osteotomy and root resection microsurgeries.

The shaping ability of manual ProTaper on mandibular second molars / 实用口腔医学杂志

Investigate the cleaning ability of manual ProTaper on mandibular second molars with C-shaped (c-shaped root) or normal root canal(separated root). Twenty mandibular second molars with C-shaped root or with separated roots were sectioned at 3.0, 5.5 and 8.0 mm from the root apex. The images of pre-preparation and F1, F2, and F3-prepapared of manual ProTaper were captured respectively. The cross-sectional areas of the canals were measured and the formula of area after treatment/area before treatment was used to calculate the area ratio. The data were analyzed by SPSS 10.0. The results showed that there was no statistically difference between cross-section root canal area ratios in two groups. Significant differences were found between the cross-section canal area ratio of F1 and F2, F1 and F3 at section 5 mm of S group, and F1 and F3 at section 3 mm of C group. The results suggested that the increasing of cross-section ratio of the two kinds of canals was not obviously concerned with their anatomical morphology.

Evaluation of preparation of curved root canals using hand-used ProTaper / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the shaping ability of hand-used ProTaper on curved canals using Endodontic Cube.</p><p><b>METHODS</b>Fifty-four curved root canals in vitro were selected and divided into three groups according to the curved degree (alpha), group A: 0 degrees < or = alpha < 25 degrees , group B: 25 degrees < or = alpha < 40 degrees , group C: 40 degrees < or = alpha < 55 degrees . Endodontic Cube was assembled, and each sample was sectioned perpendicular to the axis of the tooth into four sections with Isomer-Buhler in low speed. Then the root canals were prepared with hand-used ProTaper. Before and after shaping, photograph of all the sections were taken under a stereomicroscope. Statistical analyses were performed.</p><p><b>RESULTS</b>The dentin cutting quantity of the whole canal prepared with ProTaper in group B and C was larger than that of group A. The deviation distance of the whole canal prepared by ProTaper in group C was significantly larger than that in group A, and the deviation distance in middle portion larger than that in group B. The maintaining ability in the middle portion of group C by ProTaper was worse than that of group A and B.</p><p><b>CONCLUSIONS</b>The curvature of root canal may increase the cutting quantity of the -dentin and reduce the ability of remaining original canal shape prepared by ProTaper.</p>

Mutations in the ED1 gene in families with X-linked hypohidrotic ectodermal dysplasia / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To detect mutations in the ED1 gene in two Chinese pedigrees and a sporadic case with X-linked hypohidrotic ectodermal dysplasia (XLHED) and provide evidences with the mutation analysis for genetic counseling, prenatal diagnosis and confirmation of carrier status.</p><p><b>METHODS</b>Peripheral blood samples were obtained from two pedigrees and the sporadic patient, and genomic DNA was extract by salting out method. Polymerase chain reaction (PCR) and direct sequencing were performed to screen mutations in ED1 gene.</p><p><b>RESULTS</b>Three mutations were identified. In one of the pedigrees, a 1045G > A transition was evidenced in exon 9 that resulted in a change of Ala 349 Thr. In the other pedigrees and the sporadic patient, 467G > A and 466C > T transitions were demonstrated in exon 3 that resulted in change of Arg 156 His and Arg 156 Cys. These mutations were not found in 100 normal individuals.</p><p><b>CONCLUSIONS</b>These mutations were responsible for the disease in the two families and the sporadic patient. All these mutations had been identified previously.</p>

Location of GbpC protein in Streptococcus mutans UA159 / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine whether the glucan binding protein C (GbpC) with LPXAG motif is anchoring to the cell wall of the Streptococcus mutans UA159 (S. mutans UA159).</p><p><b>METHODS</b>S. mutans UA159 GbpC C terminal gene segment was amplified by PCR, the gene sequences and the deduced amino acid sequences were analyzed. In order to locate the GbpC of S. mutans, the study isolated the wall fraction following digestion of the cell wall by N-acetylmuramidase, and the GbpC was detected by Western blot analysis. GbpC S. mutans UA159 was located with gold particles. Furthermore, the dextran-dependent aggregation (ddag) phenotype of the S. mutans UA159 under stress condition was observed.</p><p><b>RESULTS</b>S. mutans UA159 GbpC C-terminal LPXTG motif was replaced by LPXAG motif. GbpC was observed in the cell wall component and immunogold experiment showed that the gold particles distributed around the cell wall surface. S. mutans UA159 exhibited ddag+.</p><p><b>CONCLUSIONS</b>GbpC with LPXAG motif was still anchoring to the cell wall.</p>

Immunolocalization of Secretion complex in Streptococcus mutans / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the distribution pattern of the Secretion complex in Streptococcus mutans by means of the subcellular localization of SecA and SecY.</p><p><b>METHODS</b>The specificity of anti-SecA antibody and the anti-SecY antibody were examined by Western blot. An indirect postembedding immunogold method was used to determine the subcellular localization of the SecA and SecY in the cytoplasmic membrane of the Streptococcus mutans GS-5.</p><p><b>RESULTS</b>Immunoblotting results showed that the anti-SecA antibody and the anti-SecY antibody specifically recognized a single band of about 95 000 and 47 800 respectively. Immunogold electron microscopy revealed a single intense focus of gold particles at a discrete location on the cytoplasmic membrane of the Streptococcus mutans GS-5.</p><p><b>CONCLUSIONS</b>SecA and SecY clustered to an asymmetric microdomain, which suggests that Sec complex present a uni-site on the cytoplasmic membrane of Streptococcus mutans.</p>

Survey of root canal curvature in maxillary anterior teeth / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate root canal curvature in maxillary anterior teeth.</p><p><b>METHODS</b>About 400 human maxillary anterior teeth were examined by indirect digital radiography both from labiolingual and mesiodistal directions. The root canal curvature was analyzed.</p><p><b>RESULTS</b>The major sort of maxillary anterior teeth was type I. The proportion of maxillary center incisors, maxillary lateral incisors, maxillary canines curved in mesiodistal were 11.17%, 16.19% and 21.43%, in labio-lingual were 39.59%, 40.00% and 29.59%, both in labiolingual and mesiodistal directions were 4.60%, 35.24% and 24.49%. About 50% of maxillary anterior teeth were moderate curve, the degree of root canal curvature of maxillary canines was larger than that of maxillary incisors, and radius of curvature and length of the curved part of root canal of maxillary canines were smaller than that of maxillary incisors.</p><p><b>CONCLUSION</b>Root canal curvature in maxillary anterior is complex, especially in maxillary canine. In order to improve quality of root canal therapy, we need to understand types of root canal, degree of root canal curvature and radius of curvature completely.</p>

A study of the physicochemical and biological properties of mutanase from Trichoderma harzianum / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine the physicochemical properties of the mutanase of Trichoderma harzianum isolated from China and to study the influence of mutanase on the adherence of oral Streptococci and the structure of oral biofilms.</p><p><b>METHODS</b>Six fungal strains belonging to Trichoderma were tested for mutanase production in the same cultural condition, the strain producing the highest mutanase activity was studied further and the pH and temperature optimum of the enzyme was determined. The RT-PCR method was used to obtain the gene coding for mutanase and the product was cloned to pMD18-T simple vector for sequencing. Inhibition effects of mutanase on the adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 were studied by adherence test. The optical sectioning of biofilms with or without mutanase supplementation were analyzed by confocal laser scanning microscopy (CLSM).</p><p><b>RESULTS</b>The highest enzymatic activity was achieved by Trichoderma harzianum Th1, the maximum activity was at pH 5.5 and at 40 degrees C. The nucleotide sequence was 92% homology with that of a known gene coding a mutanase (GenBank accession No. AJ243799). The adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 was significantly inhibited by mutanase. Compared with control, the biofilms with mutanase supplementation had lower height and sparser structure.</p><p><b>CONCLUSIONS</b>The mutanase from Trichoderma harzianum Th1 can inhibit the adherence of oral Streptococci and had an influence on the structure of oral biofilms.</p>

Comparison of penetration and obturation density using nickel-titanium and stainless-steel spreader in curved canals / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the initial penetration depth of nickel-titanium (NiTi) and stainless-steel (SS) spreader during lateral compaction and the quality of the seal in curved canals.</p><p><b>METHODS</b>Forty extracted mandibular premolars with a single curved canal were divided into two groups: no more than 20 degrees and more than 20 degrees based on degree of curvature. All canals were instrumented using a rotary instrumentation technique. NiTi and SS spreaders were used to obturate the canals containing a master cone while the penetration depths were measured. Horizontal sections were cut in 2 and 4 mm from the apex and photographed under stereomicroscope. The percentage of gutta-percha-filled are (PGP) of cross-sections was measured using an image analysis program.</p><p><b>RESULTS</b>In canals of more than 20 degrees, the penetration depths and PGP of 2 mm from the apex of NiTi spreaders were higher than SS spreader. In canals of no more than 20 degrees, there were no significant difference between them (P > 0.05). At 4 mm from the apex, there was no significant difference between two groups.</p><p><b>CONCLUSION</b>NiTi spreaders has a higher penetrated depth and obturation density than SS spreaders in severed curved canals.</p>

Expression pattern and level of cytotoxic T lymphocyte-associated antigen-4 targeted anti-caries plasmids in eukaryotic cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate and compare the expression pattern and level of targeted anti-caries plasmids encoding different-size antigens in eukaryotic cells.</p><p><b>METHODS</b>The A-P fragment of PAc (surface protein antigen) was removed from pGJA-P encoding the signal peptide, extracellular domains of human CTLA-4, human Ig hinge, CH2 and CH3 domains, A-P fragment of PAc and GLU (glucan binding domain) region of GTF-I of Streptococcus mutans, to obtain the plasmid pGJGLU. pCI vector skeleton of pGJA-P or pGJGLU was replaced by pVAX1 to construct plasmids pGJA-P/VAX and pGJGLU/VAX. CTLA4-Ig-GLU fragment was removed from pGJGLU and inserted into the vector pEGFP-N1 to obtain the recombinant plasmid pGJGLU/GFP. The CHO cells were transfected with those plasmids by using liposome and the expression of fusion protein was observed with fluorescence microscope. ELISA was used to detect the expression level of fusion proteins in cultured supernatants.</p><p><b>RESULTS</b>Specific vesicles with green fluorescence could be observed in the CHO cells transfected with pGJGLU/GFP. The recombinant fusion protein could be detected in the cultured supernatants of CHO cells transfected with pGJA-P/VAX, pGJGLU/VAX and pGJGLU/GFP, of which the concentration was different. The highest concentration of recombinant fusion protein was observed in the supernatants of CHO cells transfected with pGJGLU/VAX.</p><p><b>CONCLUSIONS</b>CTLA-4 targeted fusion protein could be expressed and secreted by eukaryotic cells. The size of antigen may affect the expression level of CTLA-4 targeted anti-caries DNA vaccine.</p>

Clinicopathologic analysis and genetic investigation of two families with cherubism / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study genetic feature, clinical and histopathological characteristic of two Chinese kindreds with cherubism (CBM).</p><p><b>METHODS</b>Two Chinese kindreds with CBM were investigated. The affected individuals of two families were analyzed with medical history, clinical manifestations, classified grading system, radiographic assessment, histopathological findings, and hereditary nature.</p><p><b>RESULTS</b>There were 2 individuals affected with CBM in family A and 3 patients involving three generations in family B. Two probands were diagnosed aggressive form cherubism and classified as grade IV. In histopathological findings, besides varying numbers of multinucleated giant cells in a stroma of fibroblasts and the eosinophilic cuffing surrounding some vessels, actively proliferating areas with clear mitoschisis and relative dormant areas with loose fibrous tissue and bone were also presented in microscopic fields of the lesion.</p><p><b>CONCLUSIONS</b>Cherubism is caused by autosomal dominant inheritance. The diagnosis should be based on the genetic, clinical, radiological, and pathological aspects of the disease.</p>

Analysis on results of endodontic treatment and influencing factors / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To assess the clinical outcome of root canal therapy (RCT) and the various factors that may influence the outcome of RCT.</p><p><b>METHODS</b>A total of 695 teeth from 357 patients were retrospectively studied three years after endodontic treatment. Pre- and intra-operative information was collected from the original patient records. The post-operative sign or symptom, periapical status and coronal restoration integrity were examined 3 years after obturation. Data were subjected to bivariate and multivariate analysis.</p><p><b>RESULTS</b>The cure rate for 695 teeth was 75.1%, 96.0% of which was considered to be functional. The tooth group, pre-operative pulp and periapical status, quality of root filling and integrity of coronal restoration were revealed by means of bivariate analysis to exert a significant influence on treatment outcome. The logistic analysis indicated that the odds for cure in the teeth with pre-operative periapical radiolucency, underfilling and "open" coronal restoration were significantly lower by 2 folds, 3 folds and 1.6 folds than their counterparts, respectively.</p><p><b>CONCLUSIONS</b>The pre-operative periapical status, quality of root filling and the integrity of coronal restoration are main predictors of outcome in RCT.</p>

Ultrastructure of the taste pores and taste pits of human taste buds / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the ultrastructural features of taste pores and taste pits of human taste buds.</p><p><b>METHODS</b>Three samplers obtained randomly from adults were divided into two perts, and transmission electron microscopy and scanning electron microscopy were used to observe the fine structure of taste buds in human circumvallate papillae.</p><p><b>RESULTS</b>The longer diameter of the taste pores was 1.02 - 7.36 microm, and most of taste pores contained no taste hair and dense material, and the profile of taste pit was triangular.</p><p><b>CONCLUSIONS</b>Taste hair and dense material were seldom observed in most of taste pores.</p>

The value of endoscopy for the diagnosis and treatment of obstructive salivary gland diseases / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the value of sialoendoscopy in the diagnosis and treatment of chronic obstructive sialadenitis (COS).</p><p><b>METHODS</b>25 patients (34 sides) who complained of recurrent swelling in the salivary gland region were selected for study from Jan. 2003 to Jun. 2003 at the Department of salivary gland diseases, School of Stomatology, Wuhan University, including 19 parotid cases (27 sides) and 6 submandibular gland cases (7 sides); 16 females and 9 males. And their age range was 17 - 77 years, with an average of 43.72 years. Before sialoendoscopy, 22 parotid cases underwent sialography, and 3 submandibular gland sialoliths cases received an additional standard mandibular occlusal film examination.</p><p><b>RESULTS</b>Conventional radiographs revealed that 3 cases had submandibular gland radiopaque stones, and 22 had COS. Dilatation of main duct of parotid and submandibular gland were also found in the radiographs. Sialoendoscopy showed: proliferative fibrous materials in the duct; stenosis or dilatation of duct; vasodilatation, erythema on the wall of the duct; mucoid plugs and pyogenic plugs; irregular lumen shape; radiopaque and radiolucent stones.</p><p><b>CONCLUSIONS</b>Sialoendoscopy may be a safe, effective, and minimal invasive method in the diagnosis and treatment of COS.</p>

The study of salivary-SIgA reaction to Streptococcus mutans in acid environment / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To test the salivary immunoglobulin A antibody activity to Streptococcus mutans in normal with in acid environment.</p><p><b>METHODS</b>Streptococcus mutans strains were isolated from 20 volunteers, serotyped by biochemical test and PCR, and genotyped by AP-PCR. Unstimulated secretions from submandibular glands and sublingual glands were collected from volunteers by modified collectors. Each identified Streptococcus mutans genotype was cultured in two groups: control group was cultured in BHI broth pH7.2 at 37 degrees C for 2 h; acid shock group were cultured in TYEG broth (pH5.5) at 37 degrees C for 2 h. Analysis of SIgA activity to Streptococcus mutans genotypes in different groups was detected by Western blot.</p><p><b>RESULTS</b>(1) The SIgA of each individual could response to his own Streptococcus mutans strains and the reference strains; (2) The same individual had different SIgA activity to different genotype strains; (3) There were no significant difference between acid groups and control groups, in spite that some bands had strong or weak intensity.</p><p><b>CONCLUSIONS</b>Although Streptococcus mutans could express acid shock proteins in stress, the present study suggests that these new proteins have no qualitative effect on the reaction of SIgA to Streptococcus mutans.</p>

Chitosan-DNA microparticles as mucosal delivery system: synthesis, characterization and release in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mucosal immunity is important to defense against dental caries. To enhance mucosal immunity, a DNA vaccine mucosal delivery system was prepared by encapsulating anticaries DNA vaccine (plasmid pGJA-P/VAX) in chitosan under optimal conditions and the characteristics of the microparticles was investigated. Furthermore, the release properties and protective action of microparticles for plasmid were studied in vitro.</p><p><b>METHODS</b>Plasmid loaded chitosan microparticles were prepared by complex coacervation. Three factors, concentration of DNA, sodium sulfate, and the chitosan/DNA ratios in complexes [better expressed as N/P ratio: the number of poly nitrogen (N) per DNA phosphate (P)] influencing preparation were optimized by orthogonal test. The characteristics of microparticles were evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). DNA release rate of microparticles in similar gastro fluid (SGF) or similar intestinal fluid (SIF) at 37 degrees C was determined by ultraviolet spectrophotometry.</p><p><b>RESULTS</b>High encapsulation efficiency (96.8%) was obtained with chitosan microparticles made under optimal conditions of 50 mmol/L Na2SO4, 200 microg/ml DNA and N/P ratio of 4. The size of particles was about 4 to 6 microm. The encapsulation process did not destroy the integrity of DNA. When incubated with SIL, after a release of about 10% in the first 60 minutes, no further DNA was released during the following 180 minutes. When incubated with SGL, the microparticles released a small burst (about 11%) in the first 60 minutes, and then slowly released at a constant, but different rate.</p><p><b>CONCLUSIONS</b>These chitosan microparticles showed suitable characteristics in vitro for mucosal vaccination and are therefore a promising carrier system for DNA vaccine mucosal delivery.</p>

Preliminary study on gene related to acid tolerance of Streptococcus mutans / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To construct an acid-sensitive mutant of Streptococcus mutans (S. mutans) by transposon mutagenesis and to find a new gene related to the acid tolerance of S. mutans.</p><p><b>METHODS</b>The transposon Tn917 was delivered into S. mutans UA159 by the temperature-sensitive plasmid pTV1-OK bearing Tn917 and transposition of Tn917 was induced after incubation at non-permissive temperature (42 degrees C). Transposants harboring Tn917 in the chromosome were screened for the selection of mutant that had diminished growth at low pH. Southern analysis was performed with EcoRI (no cut within Tn917) digests of S. mutans UA159 and the selected aid-sensitive mutant, with DIG-labeled probe of 4.3 kb KpnI fragment of pTV1-OK containing Tn917. Genetic backcross experiment was performed by transforming the genome of the mutant to another S. mutans strain MT8148 to determine the linkage of Tn917 insertion to the change of phenotype (acid-sensitivity). Comparison of the abilities to grow at low pH, the glycolytic pH drop and killing pH values were done between the acid-sensitive mutant and the parent strain. The asymmetric PCR method was used to obtain the fragment flanking Tn917 and the PCR products were cloned to pMD18-T vector for sequencing.</p><p><b>RESULTS</b>One mutant that showed no growth at pH 5.0 was isolated from 2 316 transposants and was named as b23. Southern analysis and genetic backcross experiment confirmed the linkage between single Tn917 insertion into the chromosome and the phenotypic change (acid sensitive). b23 was less acid tolerant than UA159 in that it showed poorer growth at low pH and higher glycolytic pH minimum and higher killing pH. BLAST results indicated that Tn917 inserted into the genome of S. mutans UA159 at the site of 996 123 bp.</p><p><b>CONCLUSION</b>An acid-sensitive mutant of S. mutans was successfully constructed and a new gene that is responsible for the acid tolerance in S. mutans UA159 was revealed.</p>

The effect of left bacteria in the root canal on prognosis of the root canal therapy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effect of the left bacteria on the root canal therapy.</p><p><b>METHODS</b>50 single-rooted teeth with chronic apical periodontitis were divided into two groups, one was instrumented with step-back technique and 2.5%NaOCl ultrasonic irrigation for 3 min, then filled with Thermafil. Samples were taken after instrumentation to culture. The other was treated with traditional RCT at three visits.</p><p><b>RESULTS</b>In 24 months the apical radiolucency were greatly reduced in all cases. There weren't significant relationship among the postoperative pain and the left bacteria, the degree of the obturation or the pre-operative symptoms (P > 0.05).</p><p><b>CONCLUSION</b>The effect of left bacteria in root canal filled with Thermafil wasn't observed.</p>

Immunization of rats with a targeted fusion anticaries DNA vaccine / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the expression of a targeted fusion anticaries DNA vaccine pGJA-P in situ. To compare the levels of specific antibodies and anticaries efficacy generated by pGJA-P and pGLUA-P, a fusion anticaries DNA vaccine.</p><p><b>METHODS</b>pGJA-P was administrated intramuscularly or intranasally to rats, and the expression of recombinant protein was detected by immunohistochemistry technique. Wistar rats were fed a cariogenic diet and orally infected with S. mutans, then immunized with pGJA-P or pGLUA-P via the intramuscular or intranasal route. All rats received a booster immunization 2 weeks later. At the termination of the experiment, blood and saliva samples were collected for assay of antibodies by ELISA and jaws were obtained for caries evaluation by the Keyes method.</p><p><b>RESULTS</b>Recombinant protein could be detected in muscle in intramuscularly immunized rats and in nasal mucosa in intranasally immunized rats. Rats immunized intramuscularly with pGJA-P had significantly higher serum IgG levels than others (P < 0.01). Rats immunized intranasally or intramuscularly with pGJA-P had significantly higher salivary IgA levels than others (P < 0.01). Keyes scores of pGJA-P groups were significantly lower than those of pGLUA-P groups and pCI groups (P < 0.01).</p><p><b>CONCLUSIONS</b>pGJA-P could be correctly expressed in vivo. pGJA-P generated increased humoral immune response and anticaries efficacy compared with pGLUA-P.</p>