Objective:To evaluate the effect of autogenous graftin g material of the maxillary tuberosity harvested by Mx grafter in the application of immediate implantation . Methods: 25 implants were i mmediately placed in tooth extraction sockets in 21 patients (7 females and 14 males) respectively, Autogenous grafting material of maxillary tuberosity harve sted by Mx grafter was used as a gap filling or defect restoring material arou nd screw type root form implant. Defect height and width were measured at the ti me of implant placement and at second stage surgery. Results: 3～4 months postoperatively, all implants demonstrated clinical stabilit y and the gap or defects were replaced with newly formed bone at second stage s urgery.All the implants were in function. Conclusions: Th e technique described affords a simplified and predictable manner for placement of implants into immediate tooth extraction sockets.

OBJECTIVETo photoelastically investigate the difference in load distribution of Tension More (TM) implants with different conical angle designs.

METHODSThe following five groups of implants of different conical angles were designed: cylinder implant, upper 1/3 TM implant (taper length of 3 mm); 1/2 TM implant (taper length of 5 mm); lower 1/3 TM implant (taper length of 7 mm); and bottom TM implant (taper length of 10 mm). The implants were centrally located in individually photoelastic models consisting of a simulated trabecular bone and a 1 mm-thick layer of cortical bone. Vertical and 45° oblique static loads were applied at the center of the superstructures. The resulting stresses were monitored photoelastically and recorded photographically. RESULTS With vertical loading, the cylinder implant showed higher stress levels in the cortical bone and trabecular bone than the upper 1/3 TM implant, 1/2 TM implant, and lower 1/3 TM implant. The four groups of TM implants showed lower stress levels in the cortical bone than the cylinder implant under oblique loads. The least favorable stress concentration in cortical bone was observed in the upper 1/3 TM implant under vertical and oblique loads.

CONCLUSIONTM implants of rational conical angle designs seem to be effective in stress distribution. For all designs and load directions, the upper 1/3 TM implant is the most favorable around the crest.

Bone and Bones ; Dental Implants ; Stress, Mechanical

BACKGROUND: Fibrous scaffolds prepared by electrospinning possess similar structure to extracellular matrix, and exhibit convenience in introducing bioactive ceramics into polymer matrices, which have distinct superiority in making bone tissue scaffolds materials.OBJECTIVE: To evaluate the bioactivity of gas-jet/electrospun nanosized hydroxyapatite (nHAP)/poly (3-hydroxybutyrate) (PHB) scaffolds for being used as bone tissue engineering scaffolds.DESIGN, TIME AND SETTING: The in vitro cytology experiment was performed at the State Key Laboratoty of Oral Diseases,Sichuan University between March 2008 and April 2009.MATERIALS: The gas-jet/electrospun PHB and 10% nHAP/PHB scaffolds were prepared.METHODS: Rats bone marrow-derived mescenchymal stem cells were incubated on the nHAP/PHB scaffolds were served as experimental group, incubated on the PHB scaffolds were as control group, and cells incubated on cell culture plate were consided to be blank control group.MAIN OUTCOME MEASURES: mRNA transcript expression of bone-related markers, including alkaline phosphatase, type I collagen, and osteocalcin, were quantified utilizing reverse transcription-polymerase chain reaction (RT-PCR) at day 14 after culture.RESULTS: After 14 days, the bone-related markers were expressed in three groups, and had higher transcript levels in the cells cultured on the nHAP/PHB scaffolds than those on the PHB scaffolds and cell culture plate.CONCLUSION: The gas-jet/electrospun nHAP/PHB scaffolds present good bioactivity in vitro and have the potential to be used in bone tissue engineering.

Objective To investigate the clinical results of immediate loading of a single anterior implant. Methods 26 implants were placed into anterior sites. Provisional prosthesis were placed at the time of fixture placement. It did not occlude in any pathway. Restoration was for esthetic only, not for function. Results No fixture was lost since the immediate restoration was delivered, the minimum being 12 months and the maximum 72 months. Conclusion Clinical studies on the placement of immediate restoration in anterior implant of maxilla have revealed predictable results.

Objective:To evaluate the effect of surgical c ro wn-lengthening and restoration procedure in the treatment of short clinical cro wn in anterior tooth. Methods: 28 short clinical crowns of 5 pat ients were lengthened through operation. 6 weeks after operation metal-fused ce ramic prosthesis was individually prepared.Results: Post-operat ion follow-up was performed 6 weeks after treatment,the average length of the c rown of the anterior tooth increased by (2.9?0.6) mm. No complication was obs erved. All the patients were satisfied with the esthetic effects one year after restoration.Conclusion: Surgical crown-lenthening and prosthesi s procedure may be used in the treatment of the short clinical crown.

Objective To study the impact of the number of functional natural teeth (FNT) and different oral restoration behaviors on well-being of the elderly.Methods The elderly residents of Guangzhou Haizhu District were acted as respondent,WHO-5 Scale was the measurement instrument of well-being.Analysis of covariance was used to correct confounding factors and analyze the corrected data,and then it was compared by LSD Test.Resuits (1) The results of analysis of covariance showed that,average scores on WHO-5 Scale were not all the same among different groups which were divided by different number of FNT or different oral restoration behaviors (Respectively:F=21.547,P＜0.001 ; F=141.219,P＜0.001).(2) The results of LSD Test showed that,although there were no statistical differences in corrected average scores between group with 5-9 FNT and group with 10-14 FNT (LSD-t=-0.536,P=0.593),differences had statistical senses between other groups(P＜0.01).All scores were ordered from the least to the most number of FNT,and they were (11.786±5.270),(15.724±4.036),(15.934±3.957),(18.941±2.616) and (23.390±6.951) respectively.It also showed that,there were no statistical differences in corrected average scores between the perfect oral restoration behavior group,the imperfect oral restoration behavior group and the no oral restoration behavior group(respectively:(23.056±4.772),(20.647±2.660),(14.872±7.313) ; P＜0.01).Statistical differences were also found in corrected average scores between the imperfect oral restoration behavior group and the abnormal oral restoration behavior group (respectively:(20.647 ±2.660),(14.565±2.914);LSD-t=13.108,P＜0.01).No statistical differences were found in corrected average scores between the no oral restoration behavior group and the abnormal oral restoration behavior group(respectively:(14.872±7.313),(14.565±2.914) ; LSD-t=-0.696,P＜0.01).The differences in corrected average scores between the needless oral restoration behavior group and the perfect oral restoration behavior group also showed no statistical significance (respectively:(22.848± 8.068),(23.056± 4.772) ; LSD-t =-0.340,P =0.734).Conclusion Well-being of the elderly may be associated with number of FNT and oral restoration behaviors.

Objective: To evaluate the effect of pure titanium modified by bioadhesive RGD peptide on the early attachment, growth and proliferation of osteoblasts. Methods: The titanium samples were hydroxylated by alkali/hot water aging and sol-gel layer-by-layer deposition technique. Afterwards, the terminal -NH_2 group was introduced to the titanium surface by organosilane APTMS self-assembled monolayers and the functional group -NH_2 was further reacted with EDC/NHS by which RGD peptides was covalently immobilized to titanium. The efficiency of this bioreactive surface in promoting cell attachment and the competitive inhibition effect of RGD peptide with different concentrations were observed by calculating the amount of osteoblasts attached on the modified titanium. The growth and proliferation were observed by MTT method and scanning electronic microscopy. Results: The cell adhesion percentage of the RGD modified titanium group was much higher than that of the other groups. The RGD peptide solutions with higher concentration had stronger inhibitory impact on the cell adhesion onto the titanium surface. The cell growth, morphology and proliferation on the RGD peptide modified titanium were better than other groups. Conclusion: Bioadhesive peptide can be chemically grafted onto the titanium surface by means of self-assembled monolayers technique. The cells′ biological behaviors on the surface of RGD immobilized titanium are greatly improved in vitro.

OBJECTIVETo evaluate the application and the effect of edentulous ridge expansion(ERE) technique in maxillary endossenous implant placement.

METHODS49 patients with maxillary alveolar ridge atrophy received edentulous ridge expansion using condenser. In order to be similar to natural root, dental implants were selected and placed to tooth missed sites according to the requirements of aesthetics, function and dimension.

RESULTS49 patients with atrophied alveolar ridge received 86 implants. The labio-lingual width augmented from 3.3 to 5.4 mm and the alveolar ridge height from 2 to 7 mm 6 months after operation. The implants osseintergrated tightly with alveolar bone and second-step prosthesis was performed 6 months after implant placement.

CONCLUSIONThe edentulous ridge expansion technique can meet the requirements of aesthetics and function and is applicable to endossenous implant placement in maxilla. The method is simple and valuable to clinical application.

Adolescent ; Adult ; Alveolar Ridge Augmentation ; methods ; Atrophy ; surgery ; Dental Implantation, Endosseous ; methods ; Female ; Gingiva ; pathology ; Humans ; Jaw, Edentulous, Partially ; surgery ; Male ; Maxilla ; Middle Aged ; Osseointegration

Objective:To compare the maxillary sinus mucosa's stress distribution when elevated by three lift materials.Methods:Three Finite element models of maxillary sinus mucosa with 0.3 mm thickness elevated by implant,grafting autogenous cancellous bone and hydroxyapatite respectively were established in the specific units.ANSYS finite element analysis software was used to evaluate maxillary sinus mucosa deformation by the simulated closed sinus lift surgery.Differences of Von Mises stress values of mucosa surface were calculated when maxillary sinus mucosa lift height was increased from 1 mm to 5 mm according to the a large deformation theory. Results:The Von Mises stress values on membrane surface elevated by implant,grafting autogenous cancellous bone and hydroxyapa-tite bone substitute materials showed no difference within 5 mm elevation.Conclusion:Closed maxillary sinus floor lifting operation with implant elevating the maxillary sinus membrane directly is a simple and minimally invasive way for sinus floor elevation.

BACKGROUND:How to avoid iatrogenic maxil ary sinus mucosal perforation after closed maxil ary sinus augmentation.
OBJECTIVE:To compare the influence of maxil ary sinus mucosa at different thicknesses on the mucosal perforation in closed maxil ary sinus augmentation operation by using finite element analysis.
METHODS:Three finite element models of maxil ary sinus mucosa at different thicknesses of 0.3 mm, 0.5 mm, 0.8 mm respectively and implant with 4.2 mm diameter were established in the SHELL63 units. ANSYS finite element analysis software was used to evaluate maxil ary sinus mucosal deformation by the simulated closed maxil ary sinus augmentation surgery. Differences of Von Mises maximum stress values of mucosa surface were calculated according to the non-linear large-deformation theory.
RESULTS AND CONCLUSION:When maxil ary sinus mucosa height was increased from 1 mm to 5 mm, the large deformation was observed in the center of mucosa center. The maximum stress curve slope was shifted mild between 1-4 mm deformation, while shifted abruptly after 4 mm. There was no difference in the value of Von Mises maximum stress values between three maxil ary sinus mucosa at 0.3 mm, 0.5 mm, 0.8 mm thickness, when the lift height was increased from 1 mm to 5 mm (P>0.05). Maxil ary sinus mucosa are faced with a higher risk of mucosal perforation and elastic elongation when maxil ary sinus height is increased more than 4 mm. Maxil ary sinus mucosa at 0.3-0.8 mm thickness are faced the similar risk of mucosal perforation in closed maxil ary sinus augmentation operation within 5 mm. While more considerations should be paid on patients with less than 0.3 mm maxil ary sinus mucosa thickness.