Development of a biomechanical model for dynamic occlusal stress analysis / 国际口腔科学杂志·英文版

The use of traditional finite element method (FEM) in occlusal stress analysis is limited due to the complexity of musculature simulation. The present purpose was to develop a displacement boundary condition (DBC)-FEM, which evaded the muscle factor, to predict the dynamic occlusal stress. The geometry of the DBC-FEM was developed based on the scanned plastic casts obtained from a volunteer. The electrognathographic and video recorded jaw positional messages were adopted to analyze the dynamic occlusal stress. The volunteer exhibited asymmetrical lateral movements, so that the occlusal stress was further analyzed by using the parameters obtained from the right-side eccentric movement, which was 6.9 mm long, in the stress task of the left-side eccentric movement, which was 4.1 mm long. Further, virtual occlusion modification was performed by using the carving tool software aiming to improve the occlusal morphology at the loading sites. T-Scan Occlusal System was used as a control of the in vivo detection for the location and strength of the occlusal contacts. Data obtained from the calculation using the present developed DBC-FEM indicated that the stress distribution on the dental surface changed dynamically with the occlusal contacts. Consistent with the T-Scan recordings, the right-side molars always showed contacts and higher levels of stress. Replacing the left-side eccentric movement trace by the right-side one enhanced the simulated stress on the right-side molars while modification of the right-side molars reduced the simulated stress. The present DBC-FEM offers a creative approach for pragmatic occlusion stress prediction.

Application of nursing clinical ladder program based on Benner theory in nurses′ stratified training / 中国实用护理杂志

Objective To explore the effect of advanced hierarchical training based on Benner theory on nurses' core competence and post competency. Methods A total of 499 nurses were selected to participat in the training from January 2016 to December 2017. They were divided into before-training group and after- training group, the training method was based on the advanced hierarchical training model of energy level under the guidance of Benner′ s theory.The nurse′ s core competence, post competency, and nursing satisfaction were compared. Results The ratings of nurses′ critical thinking and research, clinical nursing, ethics and legal practice, professional development and education consultation (34.21±4.56), (30.12±5.25), (27.12±5.24), (25.46±4.52), (26.24±4.21), (20.21±3.56), (23.12± 5.24) points in after-training group were significantly higher than in before-training group (28.36±4.12), (26.45±4.52), (26.72±4.52), (25.12±4.12), (24.50±3.25), (18.65±3.12), (20.24±4.65) points (t=7.308-21.264, P<0.05 or 0.01). The scores of nurses' professional knowledge, professional skills, professional ability, and overall quality (72.32 ± 9.21),(93.24 ± 12.35), (43.34 ± 4.12), (54.20 ± 4.23) points were significantly higher than before training (68.25±8.32), (86.42±10.21), (41.05±5.24), (52.12±5.25) points (t=6.892-9.507, P<0.05 or 0.01), and patient satisfaction 92.67％(12164/13126) was significantly higher than before training 88.68％ (11106/12524) (χ2=121.409, P<0.01). Conclusion The advanced level-stratified training model based on Benner theory is helpful to promote the development of nurses′ core competence and post competency, and improve patient satisfaction.

Occlusion: current situation and prospect in view of holistic integrative medicine / 中华口腔医学杂志

The rise of holistic integrative medicine (HIM) is an inevitable consequence of modern medical development which emphasizes the change from specialization to integration of the most advanced medical knowledge. It does not mean a simple collection of the medical theories, but means the digestion of those theories for the clinical practical application. Because occlusal therapy is characterized as not only a high level of individualization, but also a relation to many stomatology and other disciplines, such as plastic surgery, orthopedics, neurosciences and psychology. It needs the HIM to guide the clinical practice. With undertaking occlusal therapy, to avoid the limitation due to the excessive specialized disciplines, and to provide effective treatment plans for abnormal occlusion induced diseases, it is necessary to develop the discipline of the holistic integrative stomatology.

Displacement and tissue remodeling of temporomandibular joint disc / 中华口腔医学杂志

Sounding takes the highest prevalence of the signs of temporomandibular disorders (TMD). The well accepted theory of the mechanism for temporomandibular joint (TMJ) sounding is the internal derangement typically characterized by disc displacement. However, according to literature, there are approximately one third of asymptomatic joints in population had disc displacement, and, on the other hand, there are one fourth of TMJ sounding patients had not signs or very limited signs of disc displacement. Replacing the displaced disc to the normal position via methods like surgical operation did not achieve satisfactory long-term outcomes. In this review, we discuss and analyze the possible remodeling of the joint disc displacement diagnosed with imaging based on the anatomy and pathophysiology.

The influence factors of the efficiency of semiconductor laser therapy for the treatment of temporoman-dibular disorders pain / 实用口腔医学杂志

Objective:To study the influence factors of laser therapy in the treatment of temporomandibular disorders(TMD)pain. Methods:1 20 cases of TMD were treated by MDC-500 semiconductor laser therapy.VAS was valued after each treatment.The cor-relation of the VAS varians following treatment with gender and age was analysed by two way AHOVA of the repeated measurement data.Results:1 1 4 cases completed the treatment and follow-up.After each treatment the VAS decreased(P <0.001 ),in females decreased more than in males(P <0.05).There was no significant difference between age groups(P =0.208).Conclusion:Laser therapy can ease TMD pain,and is more effective for female patients.

Clinical efficacy of autologous dendritic cells and cytokine-induced killer cells combined with transcatheter arterial chemoembolization in the treatment of moderate- and advanced hepatocellular carcinoma / 实用医学杂志

Objective To investigate the clinical efficacy of autologous dendritic cells and cytokine-induced killer cells (DC/CIK) combined with transcatheter arterial chemoembolization (TACE) in the treatment of moderate and advanced hepatocellular carcinoma (HCC). Methods Sixty patients with moderste and advanced HCC were randomly divided into two groups: the experimental group (n = 32), in which the treatment of DC/CIK combined with TACE was used, and the control group (n=28), in which TACE treatment was used only. The parameters of tumor size , serum alpha-fetoprotein , survival rate , the median survival time and quality of life , were detected in patients of the two groups before and after corresponding therapy . Results ( 1 ) After receiving corresponding treatments, the efficient rates of DC/CIK combined with TACE and TACE only were 87.50% and 64.29%, respectively, with significant difference;(2) The level of serum AFP decreased in the two groups after corresponding treatment, with no significant difference; (3) The 6-month survival rate was 96.88%and 92.85%, and the 1-year survival rate was 84.38%and 64.29%, the 2-year survival rate was 65.63%and 42.86%in the experimental group and in the control group, respectively. And the median survival time was 21 months and 17 months in the experimental group and the control group, respectively, with no significant difference; (4) The quality of life was improved significantly in the DC/CIK combined with TACE group after treatment. Conclusions Administration of DC and CIK combined with TACE can prolong the survival time, increase the survival rate and especially improve the life quality of HCC patients. It is a promising approach for the treatment of patients with moderate and advanced HCC.

Changes of periodontal Ruffini's corpuscle induced by experimental tooth movement in rats / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the ultra-microscopic changes of periodontal Ruffini's corpuscle induced by different patterns of tooth movement, and investigate the influence of different changes of the periodontal mechanical environment on the periodontal mechanoreceptor.</p><p><b>METHODS</b>Thirty-two eight-weeks-old SD rats were divided into control group (n = 4), none-extraction group (n = 12) and extraction group (n = 12), and none-extraction group and extraction group were further divided into three subgroups, namely 3 day and 14 day and 28 day. For control group, no intervention was performed. For none-extraction group and extraction group, the following interventions were conducted. In none-extraction group, the maxillary left and mandibular right third molars were moved distally. In extraction group, the maxillary left third molar was moved distally, and the bilateral mandibular third molars were extracted. The ultra-structures of periodontal Ruffini's corpuscle in the periodontal ligament of the distal root of the bilateral maxillary third molars were observed under the transmission electron microscope.</p><p><b>RESULTS</b>The ultra-structrural changes in the none-extraction group were mainly characterized by degeneration or abnormal distribution of mitochondria in the axon terminal, which were almost recovered at 28 d. In the extraction group, the changes were mainly characterized by deficiency or abnormal elongation of the Schwann sheath and were not recovered at 28 d.</p><p><b>CONCLUSIONS</b>The ultra-structures of periodontal Ruffini's corpuscle might be influenced by tooth movement and occlusal changes, and the mechanorecepting function of it might be affected by changes of the periodontal mechanical environment.</p>

Effects of experimentally created unilateral anterior crossbite prosthesis on the expression of parathyroid hormone-related peptide and parathyroid hormone receptor-1 in mandibular condylar cartilage of rat / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effects of experimentally created unilateral anterior crossbite prosthesis on the expression of parathyroid hormone-related peptide (PTHrP) and parathyroid hormone receptor-1 (PTH1R) in mandibular condylar cartilage of SD rat.</p><p><b>METHODS</b>In experimental groups, the unilateral anterior crossbite metal prosthesis was cemented to the left incisors of the maxilla and mandible of 6-week-old SD rats, respectively. Animals were sacrificed at 2, 4, 8 weeks. Hematoxylin-eosin (HE) staining were carried out for studying the morphological changes of the condylar cartilage. Immunohistochemical staining and real-time polymerase chain reaction (PCR) analysis were performed to detect the levels of expression of PTHrP and PTH1R in the condylar cartilages.</p><p><b>RESULTS</b>The obvious degenerative changes were found in the condylar cartilages in experimental group at 8 weeks. Comparing to the control group, the expression of PTHrP mRNA (P < 0.01) and protein(P < 0.01) in the experimental group were increased, whereas PTH1R mRNA (P < 0.01) and protein (P < 0.01) levels were decreased.</p><p><b>CONCLUSION</b>The expression of PTHrP was increased in the condylar cartilage of rat with unilateral anterior crossbite metal prosthesis but its effects might be limited because of decreased expression of PTH1R in the condylar cartilage. The low level expression of PTH1R should be a part of the constitution of the molecular pathomechanism of temporomandibular joint osteoarthritis (TMJOA)-like lesion.</p>

Effect of gradually induced disordered occlusion on the expression of osteoprotegerin and receptor activator of nuclear factor-kappaB ligand in mandibular condylar cartilage of rats / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of gradually induced disordered occlusion (GIDO) on the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) in mandibular condylar cartilage of rats.</p><p><b>METHODS</b>Totally 48 rats, aged 8 weeks were included, and were divided into experimental and control groups randomly at 4 time points, with same gender distribution (n=3). By inserting elastic rubber band the right side mandibular first molar and the left side maxillary first molar were moved mesially. Four weeks later, the right side mandibular third molar and the left side maxillary third molar were moved distally with same method. In this way, the GIDO was established in rats. The rats were sacrificed at the end of 2th, 4th, 6th and 8th week respectively after the application of the GIDO. The expression of OPG and RANKL in condylar cartilage was examined with immunohistochemical method and calculated by the area of positive cell percentage.</p><p><b>RESULTS</b>OPG and RANKL expressed predominantly in condylar cartilage hypertrophic layer. The rats in experimental group expressed a higher OPG level in all of the 4 time points than their age-matched controls (P<0.05), while RANKL were higher in 2, 6, 8 weeks subgroups (P<0.05), but not in 4 weeks subgroup. No differences were found between male and female subgroups.</p><p><b>CONCLUSION</b>The present results suggest that both OPG and RANKL take part in the condylar cartilage remodeling procedure in the present rat model.</p>

Occlusal contact principles in prosthodontics / 华西口腔医学杂志

The occlusion contact, which is engaged in many dental clinical scopes, is the primary subject in the field of dental occlusion. Prosthodontics is one of the fields that are involved in with this subject, including the static relation (the occlusal contacts in intercuspal occlusion) and the dynamic relation (such as that in chewing movement). Not only the restorations, but also the abutments, that have to be properly managed to obtain a harmony occlusal contact relationship.

A comparative study on the intercuspal occlusion among TMD patients, malocclusion patients and university students / 中华口腔医学杂志

<p><b>OBJECTIVE</b>The relationship between occlusion and temporomandibular disorders (TMD) remains disputed. The related epidemiological studies have been carried out focused on the occlusal characteristics in motion, for example in protrusion, retrusion or laterally extension and on some of malocclusion features. Very few studies were carried out on the intercuspal occlusion which is the most important occlusal relationship. Angle's classification of occlusion and the relationship of over-jet and over-bite are two prominent features now generally used in clinical practice for occlusal evaluation. In present study two kinds of features of occlusion were compared among TMD patients, malocclusion patients and university student volunteers, who of the laters represented nature population.</p><p><b>METHODS</b>100 continued cases visiting our TMD Clinic during the year of 2 000 with complain of TMD problem, 100 malocclusion patients in continued orthodontic department records, and 268 university student volunteers were included. All subjects were with complete dentitions, except of age-related third or second molar tooth eruption difference. Study cast were obtained for all 468 subjects involved and following characters were studied. 1. Angle's classification; 2. Over-jet and over-bite relationship. Anteriorly it included cross-bite, cusp-to cusp bite, deep over-bite (without deep over-jet), deep over-jet (with or without deep-bite), open bite, and others. Posteriorly it included cross-bite, reverse cross-bite and others. 3. Abnormal occlusal index: For the purpose of quantitatively comparing the abnormal occlusal relationship of over-bite and over-jet, the occlusal index was introduced. The anterior continued abnormal was scored as 3 while posterior continued oclcusal abnormal scored as 5. The sum of the scores in the same subject was taken as his abnormal occlusion index.</p><p><b>RESULTS</b>1. Ratio of Angle's I patients in malocclusion group was significantly lower than those in TMD group and US group (P < 0.05), while the later two groups had no difference (P > 0.05). 2. The ratios of anterior cross-bite and deep over-jet were higher in malocclusion group than those in other two groups. No significant difference for the other kinds of abnormal over-jet and over-bite relationship were found among the three groups. 3. The abnormal occlusion index of malocclusion group was higher than that of US group, but not than that of TMD group which had no difference with US group either.</p><p><b>CONCLUSIONS</b>1. Aesthetic related anterior abnormal occlusion such as anterior cross-bite and deep-over-jet attract more attention of popular. But they had no relationship with TMD. 2. TMD patients had not significant occlusal features on Angle's classification and over-jet and over-bite relationship compared to malocclusion and nature population subjects.</p>

The effect of occlusal adjustment in the treatment of TMD evaluated with T-San II system / 实用口腔医学杂志

Objective:To investigate the effects of occlusal adjustment in the treatment of TMD . Methods: 7 cases of TMD were treated by occlusal adjusment and occlusal contact points were measured with T-scan II system before and after treatment . VAS pain analysis table was used to evaluate the pain control effect of occlusal adjustment method. Results:The number of occlusal contact points increased obviously after occlusal adjustment,and distribution of contact on two sides tended to be balanced.Pain release was indicated by VAS table . Conclusion: Occlusal ajustment method is necessary for the treatment of TMD

TMJ degeneration caused by gradually induced disturbed occlusion: A scanning electron microscopy study / 实用口腔医学杂志

砄bjectire: To investigate whether the disturbed occlusion can induce TMJ degeneration. Methods: 2 Rhesus female monkeys, 1 served as experimental animal and the other as the control, were included. Right mandibular first molar and left maxillary first molar of the experimental animal were extracted. Small strings were set at the missing space to pull the neighbor teeth inclined into the space and to occlude with opposite teeth in convex to convex relation. 8 months later condyles and discs of both animals were surgically obtained and prepared for scanning electron microscopy examination. Results: Gelatin like material was found over the condyle and disc surface of the control animal and obvious rigids were found on its articular surface. On the sagittal section of the condyle cells arranged in lines of each of the three layers of the soft tissue were observed. But on the top of the condyle surface of the experimental animal there was an area from media anterior to lateral posterior where the gelatin like material twisted or even disappeared here and there. There was an area where fibers were exposed. The soft tissue layers were thinner and the cellular layer was discontinued locally. The waves on the surface of middle and posterior part of the disc were disturbed and fossae like changes were found on the inferior surface. Conclusion: TMJ degeneration can be produced by gradually induced occlusal disturbance.

An own control study on the tooth attrition in natural tooth with cracked tooth syndrome patients / 实用口腔医学杂志

0.05).(2)The relative tooth attrition:significant differences between CTS and control group in upper premolar lingual cusp and lower first molar buccal cusp were found.(3)Tooth cracked direction:it was mesial-distal direction in 91.67% maxillary premolar and 88.89% maxillary second molar in CTS but no obvious direction taxis in first molar and mandibular second molar in CTS.Conclusion:There are close correlations between insufficient tooth attrition in maxillary premolar lingual cusp,mandibular first molar mesial buccal cusp and CTS.

Pain control in the treatment of temporomandibular disorders by stabilization splint / 实用口腔医学杂志

0.05).Conclusions:Occlusal splint is effective in the control of TMD pain,the treatment mechanism is related to the quick improvement of masticatory muscles.

Three dimensional analysis of the occlusion in patients with temporomandibular disorders / 实用口腔医学杂志

Objectives: To investigate the occlusion features in thre e dimensions in patients with temporomandibular disorders(TMD). Methods: Occlusal casts were obtained from 23 asymptom volunteers and 101 TMD pati ents and were analyzed in three dimensions by scores vertically, mesio-distally and labial-or buccal-lingually. Bilateral TMJs of each TMD patient was examin ed with Schuller's radiograph and tomograph, the sounding TMJs were examined wit h arthrography. The relationship between occlusion scores and the changes shown in X-ray images were analyzed. Results: 66.3% TMD patients had abnormal occlusion in vertical direction.Abnormal occlusion in vertical directio n was correlated with TMD symptoms(P 0.05 ). Conclusion: Abnormal occlus ion in vertical direction is correlated with TMD symptoms.

Histological study on temporomandibular joint disc and its attachment / 实用口腔医学杂志

Objectives: To investigate the characteristics and their functional significance of TMJ disc and its attachment. Methods: Each of the 23 TMJs from 12 cadavers were divided into quadrants sagitall y, and total 92 histological slices were obtained and stained with HE.The morpho logical characteristics of the samples was observed microscopically. Results: ①Both temporal posterior and anterior mandibualr attachment s were loose while mandibular posterior and anterior temporal attachments were d ense in which the fibers run anterior posteriorly. ②Fibers in the intermediate zone ran predominantly in anterior posterior direction while those in both ant erior and posterior bands were mixed with transverse fibers. ③At the posterior portion of disc there were 33 out of 92 slices from 6/12 cadavers (11/23 TMJs) s howed the structure of "the fourth band" which was featured by dense fibers alik e those of inner disc. There were 36 out of 92 slices from 6/12 cadavers (10/23 TMJs) showed the structure of "turned fibers" which was featured by a sudden tu rning of fibers from the thick posterior band back and downward, providing an angle like sign. Conclusions: There is great difference o f fiber direction in various parts of disc and its attachments, reflecting the functional demands.

Quality comes from exactitude:The role of functional occlusal contact in dentistry / 实用口腔医学杂志

Occlusion is a term for the contact relation between upper and lower dentitions.It is a three dimensional relationship.The vertical occlusal contact relation includes convex-to-concave contact relation between structures on occlusal surfaces of the upper and lower teeth at status of intercuspal occlusion,as well as that during protrusion,retrusion and lateral excursive movements.Occluding function depends on the contact condition of occlusion.However,the morphological criterion of the vertical occlusal contact is still lacking.Widely practical criterion for dental treatment includes only mesial-distal relation,such as one-to-two teeth contact relation between upper and low dentitions,and labial/buccal-lingual relation,such as over jet and over bite.To establish a vertical occlusal contact criterion that meets the need for individual occlusal treatment is one of the main subjects in Occlusion field.

Effect of tooth wear on morphological features of the mandibular first molars / 实用口腔医学杂志

Objective:To investigate the effect of tooth wear on the morphological features of mandibular first molars. Methods:15 extracted mandibular first molars with tooth wear and 15 without wear were investigated. Data about the morphological features of tooth were collected through the general measurement and the image measurement by electronic meter. Results:①In non-tooth-wear group, mesiodistal width of tooth was greater than buccolingual width(P0.05); ②The vertical distance between the lowest point of pulp chamber roof and occlusal surface in non-tooth-wear group was greater than that in tooth-wear group(P05); ④The distance between distolingual pulp horn and distal proximal plane was greater than that between mesiolingual pulp horn and mesial proximal plane in both two groups(P0.05). Conclusion:For different parts of tooth, the effect of tooth wear differs. As for mandibular first molars, the distal part of occlusal surface and the buccal part of distal proximal plane are susceptible to tooth wear, which is mainly due to occlusal factors and the features of biomechanical system.

The effect of occlusal disorder on the thickness of temporomandibular joint disc / 实用口腔医学杂志

Objectives: To investigate the effects of cent ra l disordered occlusion on the thickness of TMJ disc. Methods:The thickness of temporomandibular joint disc was measured in 5 cadavers with centr al disordered occlusion, including secondary malocclusion caused by loss of post erior tooth for a comparable long time with collapse of neighbor teeth and supra -eruption of its antagonized tooth, the supra-erupted third molar resulted fro m lack of antagonized tooth for a comparable long time and individual posterior tooth cross bite or reverse cross bite asymmetrically. Other 7 cadavers without central disordered occlusion served as controls. All samples were examined histo logically for the TMJ disc thickness. Out of 18 New Zealand rabbits, aged 5 mont hs, 9 were treated orthodontically to pull the first premolar move medially, occ luding with its opposite un-coincidently, central disordered occlusion was grad ually induced. The other 9 rabbits served as blank controls. The TMJs were sampl ed 3 months after beginning of the experiments, stained with HE and observed und er microscope. Results: In both cadavers and animals, the TMJ di sc was found much thicker in central disordered occlusion group than that in the control group (P