Bengazi Franco, Botticelli Daniele, Favero Vittorio, Perini Alessandro, Urbizo Velez Joaquin, Lang Niklaus P
Faculty of Dentistry, University of Medical Science, La Habana, Cuba.
Clin Oral Implants Res. 2014 Sep;25(9):1065-71. doi: 10.1111/clr.12233. Epub 2013 Jul 29.
To investigate the influence of the presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses.
In six beagle dogs, the mandibular premolars and first molars were extracted bilaterally. In the right side of the mandible (test), flaps were elevated, and the buccal as well as part of the lingual masticatory mucosa was removed. The flap was released coronally to allow a primary wound closure. In the left side, the wounds were left unsutured with the keratinized mucosa remaining (control). After 3 months of healing, a complete absence of keratinized mucosa was found at the test sites. Two recipient sites were prepared at each side of the mandible, one in the premolar and one in the molar region. A buccal bony ridge width of approximately 1 and 2 mm was obtained at the premolar and molar region, respectively. Implants were installed with the shoulder flush with the buccal alveolar bony crest, and abutments were connected to allow a nonsubmerged healing. At least 2 mm of keratinized mucosa was surrounding the control sites, while at the test sites, the implants were bordered by alveolar mucosa. After 3 months, the animals were euthanized and ground sections obtained.
A higher vertical bony crest resorption was observed at the test compared with the control sites both at the premolar and molar regions, the differences being statistically significant. The top of the peri-implant mucosa was located more coronally at the control compared with the test sites. The horizontal resorption measured 1 mm below the implant shoulder was similar at the test and control sites. Only limited differences were found between premolar and molar sites, with the exclusion of the horizontal resorption that was higher at the test compared with the control sites.
A higher alveolar buccal bony crest resorption and a more apical soft tissue marginal position should be expected, when implants are surrounded with thin alveolar mucosa at the time of installation, independently of the thickness of the buccal bony crest.
研究角化黏膜的有无对牙槽嵴顶水平的影响，以及其与不同颊侧边缘骨厚度的关系。
选取6只比格犬，双侧拔除下颌前磨牙和第一磨牙。在下颌右侧（试验侧），掀起黏骨膜瓣，去除颊侧以及部分舌侧咀嚼黏膜。将瓣向冠方松解以实现一期伤口闭合。在左侧，伤口不缝合，保留角化黏膜（对照侧）。愈合3个月后，试验侧完全没有角化黏膜。在下颌每侧制备两个受植位点，一个在前磨牙区，一个在磨牙区。在前磨牙区和磨牙区分别获得约1mm和2mm的颊侧骨嵴宽度。植入种植体，使其肩部与颊侧牙槽嵴顶平齐，并连接基台以实现非潜入式愈合。对照侧周围至少有2mm的角化黏膜，而试验侧种植体周围为牙槽黏膜。3个月后，对动物实施安乐死并获取磨片。
在前磨牙区和磨牙区，试验侧相较于对照侧均观察到更高的垂直骨嵴吸收，差异具有统计学意义。与试验侧相比，对照侧种植体周围黏膜顶端位置更靠近冠方。在种植体肩部下方1mm处测量的水平吸收在试验侧和对照侧相似。在前磨牙区和磨牙区仅发现有限差异，但试验侧的水平吸收高于对照侧。
种植体植入时若被薄的牙槽黏膜所包围，无论颊侧骨嵴厚度如何，均应预期会出现更高的牙槽颊侧骨嵴吸收以及更根尖向的软组织边缘位置。
