GAP Australasian-Dentist Issue 80 Jul-Aug 19

Category 100 AustrÀlÀsiÀn Dentist n aÀ Long-term stability of the grafted mucosa Measurements of the shrinkage of the augmentation zone over time have revealed that a substantial shrinkage reduces graft width and takes place from initial healing until three months after surgery. 3,4,6 Àhe regeneration result then stabilizes with only minimal changes. 3 Àhrinkage using autologous mucosa from the palate is approximately 33% after six months, and when using Geistlich Mucograft ® there is no significant difference at approximately 42%. 3 As for operation time, the literature concurs that using collagen matrices in comparison to using autologous transplants from the palate shortens operation time significantly by approximately 15– 20Àminutes. 4,9 Àhis, however, depends on the size of the region to be augmented and the number of grafts taken 4 and is relative when small grafts are harvested. Àegardless, in large vestibuloplasties the quantity of available autologous tissue is limited, which again justifies the use of harvest graft alternatives. Àong-term data over five years reveals comparatively stable regeneration success between autologous mucosa from the palate and Geistlich Mucograft ® 3-D collagen matrix. 3 Ànitial shrinkage after six-months remains relatively unchanged for up to five-years. When using free mucosa grafts from the palate, the total shrinkage of the augmentation zone after five years is 40.65%, and with the Geistlich Mucograft ® 3-D collagen matrix, it is 52.89%, with no significant difference. After five years with free mucosa grafts, the keratinized peri-implant soft tissue has a width of 8.4À±À2.4Àmm and 6.2À±À1.2Àmm with Geistlich MucoÀgraft ®. 3 Anticipated shrinkage should be planned in order to avoid unsatisfactory results and disease recurrence. We recommend an “over-augmentation” equivalent to anticipated shrinkage. (Fig.À2) u References 1 À Brito C, et al.: Journal of Biomedical Materials Àesearch Part B, Applied Biomaterials 2014; 102: 643-50. 2 À homa DÀ, et al.: J Clin Periodontol 2014; 41 Àuppl 15: À77-91. 3 À chmitt CM, et al.: Clin Oral Àmplants Àes 2015; 26(9): 1043-50. 4 À chmitt CM, et al.: Journal of periodontology 2013; 84: 914-23. 5 À evins M, et al.: Ànt J Periodontics Àestorative Dent 2011; 31: 367-73. 6 À anz M, et al.:À J Clin Periodontol 2009; 36: 868-76. 7 À Ghanaati À, et al.: Biomedical materials 2011; 6: 015010. 8 À ee KH, et al.: Journal of periodontal & implant science 2010; 40: 96-101. 9 À orenzo À, et al.: Clin Oral Àmplants Àes 2012; 23: 316-24. Fig 2: Vestibuloplasty with Geistlich Mucograft®. A. Clinical situation before treatment start. B. Macroscopic view of the 3-D collagen matrix with compact and cancellous layer. C. Clinical situation immediately after inserting the collagen matrix. D. Clinical situation 10 days after surgery. E. After 3 months the freshly regenerated soft tissue has matured and exhibits keratinised morphology. The freshly regenerated soft tissue is comparable in texture and colour to surrounding soft tissue. F. Clinically stable situation after 5 years. Reduction in the width of the keratinised mucosa in the course of healing (5 years). “Over-augmentation” equivalent to anticipated shrinkage is recommended in order to avoid recurrence. vascularization from the graft bed. As soon as it is applied, the matrix is impregnated with blood from the graft bed with a consequent stabilization of the blood clot. 3, 4 (Fig.À2) After surgery the patient should be asked to treat the treatment site as gently as possible. Àoft food should be recommended for 14Àdays, and patients should avoid any mechanical manipulation in the area of the graft, especially during hygiene. Chemical plaque control can be achieved with antiseptic and antibacterial oral rinsing solutions for ten-days after surgery. Àf a further flap mobilization is planned in the region, we recommend waiting for at least three months for the soft tissue to mature. (Fig.À2) Biological adaptation to the surrounding epithelium Histological examinations of human tissue samples, which were taken three- to four-months after augmentation of the keratinized mucosa using free mucosal grafts or Geistlich Mucograft ® , exhibit the characteristics of amultilayer keratinized squamous epithelium comparable to native local gingiva. 4,5 Àmmuno-histological verification of the expression patterns of the keratinization markers of the oral mucosa demonstrate the keratinization of the oral mucosa regenerated with Geistlich Mucograft ®.4 When using autologous mucosa from the palate, directly after healing and also long-term over five-years, the regenerated soft tissue in the target region shows no change in texture and color in comparison to the original graft. 3 (Fig.À1) Àhis effect, which is detrimental to esthetics, can be explained by the biological determination of the mucosa removed from the palate, which remains unchanged over time. Àhis confirms the hypothesis that autologous mucosa from the palate is revascularized basally after grafting into the target region. Àherefore, FMGs are contraindicated in the exposed aesthetic zone. 3 When using CÀGs or Geistlich Mucograft ® 3-D collagen matrix, a clinical appearance comparable to the surrounding tissue manifests after inteÀgration. Àhe reason is that the bioÀlogical information from the epithelium is absent, and an epithelial layer matching the target region forms after neo-epithelialization of the graft. 6 (Fig. 3) Fig. 3: Biological mechanisms for the formation of keratinised and non-keratinised oral mucosa after placement of Geistlich Mucograft®