Minimal invasive microscopic tooth preparation in esthetic restoration: a specialist consensus / 国际口腔科学杂志·英文版

By removing a part of the structure, the tooth preparation provides restorative space, bonding surface, and finish line for various restorations on abutment. Preparation technique plays critical role in achieving the optimal result of tooth preparation. With successful application of microscope in endodontics for >30 years, there is a full expectation of microscopic dentistry. However, as relatively little progress has been made in the application of microscopic dentistry in prosthodontics, the following assumptions have been proposed: Is it suitable to choose the tooth preparation technique under the naked eye in the microscopic vision? Is there a more accurate preparation technology intended for the microscope? To obtain long-term stable therapeutic effects, is it much easier to achieve maximum tooth preservation and retinal protection and maintain periodontal tissue and oral function health under microscopic vision? Whether the microscopic prosthodontics is a gimmick or a breakthrough in obtaining an ideal tooth preparation should be resolved in microscopic tooth preparation. This article attempts to illustrate the concept, core elements, and indications of microscopic minimally invasive tooth preparation, physiological basis of dental pulp, periodontium and functions involved in tool preparation, position ergonomics and visual basis for dentists, comparison of tooth preparation by naked eyes and a microscope, and comparison of different designs of microscopic minimally invasive tooth preparation techniques. Furthermore, a clinical protocol for microscopic minimally invasive tooth preparation based on target restorative space guide plate has been put forward and new insights on the quantity and shape of microscopic minimally invasive tooth preparation has been provided.

Measurement of the metabolites in the cortical masticatory area of patients with sleep bruxism: a magnetic resonance spectroscopy study / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine whether there are in vivo differences of metabolites levels in bilateral cortical masticatory area(CMA) of patients with sleep bruxism, compared with healthy controls using proton magnetic resonance spectroscopy(1H-MRS). Accordingly to explore if cortical control of the central jaw motor system is abnormal in sleep bruxism patients.</p><p><b>METHODS</b>Fifteen sleep bruxism patients and fifteen age- and gender-matched healthy controls underwent 1H-MRS of bilateral CMA using J-difference edited point-resolved spectroscopy sequence(MEGA-PRESS) technique. Levels of metabolites were quantified from the ratio of the metabolite integral to the unsuppressed water signal. Differences of levels of γ-aminobutyric acid(GABA), glutmate(Glu) and N-acetyl aspartate(NAA) in bilateral CMA between sleep bruxism patients and healthy controls were tested using two-way ANOVA.</p><p><b>RESULTS</b>Edited spectra were successfully obtained from the bilateral CMA in all of the participants. Levels of GABA+, glutmate and NAA in right and left CMA in sleep bruxism patients were (2.45±0.48)×10(-3), (2.35±0.62)×10(-3), (10.65±1.84)×10(-3), (10.49±2.37)×10(-3), (10.70±3.61)×10(-3), and (11.26±4.01)×10(-3) respectively. In contrast, levels of GABA+, glutmate and NAA in right and left CMA in healthy controls were (2.63±0.68)×10(-3), (2.65±0.97)×10(-3), (11.19± 1.34)×10(-3), (10.58±3.14)×10(-3), (11.82±1.80)×10(-3), and (11.95±3.23)×10(-3). There were no differences in levels of GABA+(P=0.196), Glu(P=0.590), and NAA(P=0.292) between sleep bruxism patients and healthy controls, nor in inbilateral CMA(GABA+: P=0.837; Glu: P=0.510; NAA: P=0.628).</p><p><b>CONCLUSIONS</b>The results indicate the absence of any alteration of the cortical control of the central jaw motor system in the levels of GABA, Glu and NAA in patients with sleep bruxism.</p>

The masseter motor-evoked potential after transcranial magnetic stimulation in patients with sleep bruxism / 实用口腔医学杂志

Objective:To study the masseter motor evoked potential(MEP)in patients with sleep bruxism(SB)and in healthy con-trols.Methods:30 subjects with SB and 30 healthy controls were included.MEPs were obtained by transcranial magnetic stimulation (TMS).Tests were done during daytime when the subjects were awake.The data were statistically analysed.Results:In the patients AMT was 55(52,55)%,latency of c-MEP (6.7 ±1.3)ms,the amplitude of c-MEP 0.19(0.15,0.29)mV,latency of r-MEP (2.3 ±0.4)ms,the central conduction time(CCT)4.4(3.3,5.2)ms.In the control subjects AMT was 52(52,55)%,latency of c-MEP (6.4 ±0.7)ms,the amplitude of c-MEP 0.23(0.17,0.28)mV,latency of r-MEP (2.4 ±0.4)ms,CCT 4.0 (3.4,4.4) ms.No significant difference was found between the 2 groups in the measurements evoked by TMS.Conclusion:The MEP after TMS in patients with SB is similar to that of healthy subjects,indicating that the excitability of the cortical motor system is not changed in bruxism subjects,at least when evaluated by TMS.

Investigation of nociceptive trigeminal inhibitory tension suppression system and occlusal stabilization splint on bruxism patients by using polysomnography / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the short-term effects of nociceptive trigeminal inhibitory tension suppression system (NTI-tss) and occlusal stabilization splint (OS) on sleep bruxism patients.</p><p><b>METHODS</b>Ten patients received the two splint treatments in a randomized cross-over fashion: An NTI-tss and an OS for a 1-week period, respectively. Record the bruxism episodes per hour, micro-arousals per hour of the patients before wearing the splints (baseline), the first night and 1 week after wearing the splints with polysomnography. Statistical analysis was performed with SAS 9.1 by means of mixed effect model analysis.</p><p><b>RESULTS</b>There were no differences among the micro-arousal index of the baseline, the first night and 1 week later with both types of the splints (P>0.05). The NTI-tss was associated with a significant reduction in bruxism index compared with baseline. The bruxism index of baseline, the first night and 1 week later were 7.50 +/- 1.11, 3.45 +/- 1.22, and 3.51 +/- 1.03 per hour(the first night vs baseline, t=26.52, P<0.01; 1 week vs baseline, t=26.12, P<0.01). There were also significant differences in the bruxism index after wearing the OS. The bruxism index of baseline, the first night and 1 week later were 7.44 +/- 1.23, 2.97 +/- 0.91 and 6.43 +/- 1.02 per hour(the first night vs baseline, t=16.79, P<0.01; 1 week vs baseline, t=3.79, P<0.01). Compared with the NTI-tss group, the reduction was much less, especially 1 week later.</p><p><b>CONCLUSION</b>Both the NTI-tss and the OS splints can reduce the bruxism index, and have no affect the incidence of micro-arousal. In this short term study, the NTI-tss was more effective than the OS for the treatment of sleep bruxism.</p>

A research in biomechanics of bite marks on porker limb / 生物医学工程学杂志

This research was designed to illuminate the change in biomechanical parameters of soft tissue for bite marks on porker limb. The authors used a prefabricate nob to press perpendicularly on porket limb and so to establish bite mark under three forces: 100 N, 200 N and 300 N. After the procedure of biting, the stress-strain relationship and changes in extension of soft tissue were recorded. Meanwhile, the elasticity was measured with a press meter at nine time-points. When bite mark was formed, with the development of stress, the strain of soft tissue increased. But the speed of increment slowed down when stress exceeded some extent. After bite mark was formed, the extension and elasticity of soft tissue decreased with the increase of pressure.

Analysis 22 cases of operative treatment of hip dislocation.with aretabular fracture / 中国基层医药

Objective To discuss the early stage treatment of reduction and the curative effect in coxa dislo- cation with acetabular fracture. Methods According to the different type of coxa dislocation with aeetsbular frac- ture,22 patients were given the distinctive operation and drawn reduction. As to 22 cases combination with acetabu- lar fracture and basis of difference type of the fracture were selected the method of suitable operative entrance or in- ner fixation. In this gronp,22 patients were followed up about 6 month to 3 years(average 15.3 months) after opera- tion. According to the standard of America orthopedic surgery study were commented on curative effect. Results Excellent 15 cases,well 4 casea,pass 2 cases,bad 1 case. Total fine rate were 86% .Conclusion Each kinds type of the hip dislocation cases should needed emergency reduction. The operation treatments were selected first method to settlement the bone shatter displacement in acetabular fracture or unsuitable joint and unsteady joint.