| Objectives：The purpose of this retrospective study was to evaluate theclinical outcomes of placing dental implants in the posterior maxilla using thetransalveolar technique; including success rate of the technique, cumulativesurvival rate of implants, marginal bone loss and peri-implant soft tissueparameters. Meanwhile, the elevation of sinus floor, the formation of new bone,and the pattern of bone remodeling were investigated by the radiographicanalysis. At last, the predictability of the transalveolar technique for sinus floorelevation in the presence of antral pseudocysts and the clinical outcomes wereinvestigated.Materials and methods:Part1: Between January2005and December2009, a total of94cases wereconsecutively enrolled in this study with sinus floor elevation performed usingthe transalveolar technique. Sinus membrane perforation were found at4cases. Finally,90cases,51males and39females, aged46.86±11.82years, and treatedwith126implants placed in the maxilla were actually completed. All theimplants were placed following an one-stage protocol and by one performer. Thefollow-up clinical examination include: cumulative survival rate of implants(CSR), modified plaque index (mPLI), modified sulcus bleeding index (mSBI),probing depth (PD), and peri-implant marginal bone loss (MBL). The data wereanalyzed with SPSS18.0software package.Part2: The clinical data was the same as that of Part1.4implants were lostbefore loading, and2implants dropped out. The rest of120implants wereenrolled in this study. Radiographic evaluations were conducted on panoramicand periapical radiographs at each recall. All the images of X-rays weretransferred into digital ones and storaged in the computer. The digital imageanalysis software Digimizer was used to measure the distance between twopoints. Parameters of linear measurements include: the residual bone height(RBH), the length of implant protruding into the sinus, the height of sinus floorelevation and the endo-sinus bone gain. Each measurement was performed witha precision of0.01mm, and the final value was calculated based on the averageof the three obtained values. The data were analyzed with SPSS18.0softwarepackage.Part3: The clinical data was the same as that of Part1. Two researcherswho were qualified by the standard consistency check (kappa>0.75) examinedand diagnosed whether there had an antral pseudocyst on the panoramicradiograph or not. The diagnostic criteria was: a sphere or semisphereradiopaque lesion arising at the floor of the maxillary sinus, with a clearboundary and had no damage to bone tissue. Each person observed twice, andtime interval was one week. The diagnosis are recorded only when the two results are consistent. From the original90cases,14patients were diagnosed asantral pseudocysts on the sinus floor, with14implants placed underneath thecystic regions. The clinical and radiographic evaluations were the same as thatof Part1and Part2.Results:Part1: The success rate of this surgical procedure was96.92%. After7.44±2.57months of healing, early success of implants was96.80%. During amean follow-up time of28.90±14.04months, all the implants were successfullyin function, resulting the cumulative survival rate of implant96.80%. The meanMBL was0.75±0.51mm during the healing time, and0.48±0.41mm during thefollow-up period. No statistically signicant differences were found between themesial and distal side of the implants. During the follow-up time, the meanmPLI was1.05±0.53, the mSBI0.29±0.48and the PD2.93±0.99mm.Part2: The mean RBH was7.27±1.30mm at the position of implantsplacement, the length of implant protruding into the sinus was2.77±1.15mm,and the height of sinus floor elevation was4.52±1.39mm. At the loading time,the mean endo-sinus bone gain was3.81±1.60mm. All implants gainedendo-sinus bone except9(7.5%),96implants showed new bone formationextending all around apices of implants (80%), a partial (50%-100%) growth ofnew bone was discerned towards the implant apex at15implants (12.5%). Afterthe follow-up time of28.90±14.04months, the newly formed bone on the sinusfloor underwent further remodeling with a bone reduction of0.40±0.54mm.Part3: The incidence of pseudocysts was15.56%. The success rate of thissurgical procedure conducted in the presence of antral pseudocysts was100%.The mean length of implants protruding into the sinus was2.94±1.33mm, theheight of sinus floor elevation was4.96±1.72mm. The endo-sinus bone gain after the healing period was4.32±1.26mm. Of14implants,13Implants showednew bone formation extending all around the apices of the implants (92.86%).The cumulative survival rate of implants was100%after a mean follow-up timeof29.58±15.91months. The measured height of radiographic new bonedecreased by0.64±0.48mm. No statistically signicant differences were foundbetween the endo-sinus bone gain with or without pseudocysts.Conclusions:Sinus floor elevation using the transalveolar technique represents apredictable treatment modality to insert dental implants into sites of the posteriormaxilla with reduced residual bone height. The cumulative survival rate ofimplants was96.80%, similar to the results published. The radiographic resultsindicated that elevation of the sinus floor using the transalveolar technique led toa mass of bone formation under the sinus beyond the original limits of the sinusfloor. The newly formed bone apical to the implants underwent further shrinkage.Utilizing the transalveolar technique for sinus floor elevation without removal ofantral pseudocysts is a practicable treatment for patients. A pseudocyst of themaxillary sinus is not a contraindication for sinus floor elevation, and noremoval of antral pseudocysts before or during the surgical procedure is needed. |
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