Part I of this three-part human study evaluated the formation of a new attachment apparatus (bone, cementum, and periodontal ligament) on pathologically exposed root surfaces in an open and closed environment. The most apical level of calculus on the root served as a histologic reference point to measure regeneration on root surfaces exposed to the oral environment. Attempts were made to initiate the formation of a new attachment apparatus by flap curettage, root planing, coronectomy, and submersion of vital roots beneath the mucosa. Nonsubmerged defects were treated by the same surgical technique and served as controls. Biopsies were obtained at 6 months and regeneration was evaluated histometrically by two investigators who were unaware of the treatment performed. Data from 9 patients with 25 submerged and 22 nonsubmerged defects were submitted for statistical analysis. Results indicate that a new attachment apparatus did not form in any of the 22 nonsubmerged teeth; a new attachment apparatus did form in a submerged environment (0.75 mm); significantly more new attachment apparatus (P less than 0.05), new cementum (P less than 0.01), new connective tissue (P less than 0.05), and new bone (P less than 0.02) formed in submerged defects; new cementum was cellular in nature and formed equally well on old cementum and dentin. Greater percent positive regeneration of the attachment apparatus and all component tissues occurred in submerged defects and no extensive root resorption, ankylosis, or pulp death was observed on submerged or nonsubmerged roots.
There is conflicting evidence regarding the value of graft materials in enhancing the formation of new bone, cementum, and periodontal ligament (new attachment apparatus). Part II of this study compared the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a submerged environment. The most apical level of calculus on the root served as a histologic reference point to measure regeneration on root surfaces exposed to the oral environment. Biopsies were obtained at 6-months and evaluated histometrically by two investigators unaware of the treatment performed. Data from 9 patients with 30 grafted defects and 13 nongrafted defects were submitted for statistical analysis. Results indicate that in a submerged environment significantly more new attachment apparatus (P less than .05) and new bone (P less than .05) formed in grafted than nongrafted sites. Significantly greater loss of alveolar crest height occurred in nongrafted than grafted defects (P less than .05); regeneration of new attachment apparatus, new bone, and new cementum occurred more frequently in grafted than nongrafted defects. There was a greater chance for the regeneration of a connective tissue attachment in nongrafted intrabony defects than in grafted defects; new cellular cementum formed equally well on old cementum, dentin, or both old cementum and dentin in the same defect. The periodontal ligament was oriented parallel, perpendicular, or both parallel and perpendicular in the same defect; and, no extensive root resorption, ankylosis, or pulp death was observed in grafted or nongrafted defects.
This study was designed to evaluate the potential for regeneration of a new attachment (alveolar bone, cementum and a functional periodontal ligament) in patients whose attachment apparatus had been destroyed by periodontal disease. In each of the three parts of the investigation, the most apical level of calculus on the root served as a histologic reference point to measure regeneration. In Part I, attempts were made to initiate the formation of a new attachment by surgical debridement, crown removal (coronectomy) and submersion of the vital root below the mucosa. Nonsubmerged, surgically debrided defects served as controls. In Part II, debrided intrabony defects were treated with and without demineralized freeze-dried bone allograft and the associated vital roots were submerged. Part III evaluated potential for regeneration of a new attachment in nonsubmerged roots with and without the use of demineralized freeze-dried bone allograft. Gingival grafts were placed over the experimental and control sites in an attempt to retard epithelial migration. Biopsies were obtained in 6 months and regeneration was evaluated histometrically. Preliminary results in 7 patients and 24 intrabony defects indicate that new attachment is possible on pathologically exposed root surfaces in a submerged environment with and without the incorporation of demineralized freeze-dried bone allografts. New attachment was observed on pathologically exposed root surfaces in a nonsubmerged environment when intrabony defects were grafted with demineralized freeze-dried bone allograft. New attachment was not observed on nongrafted, nonsubmerged, defects with and without the placement of gingival grafts over the defects.
There is still controversy as to the role of bone grafting materials in the formation of a new attachment apparatus and component tissues (bone, cementum, and periodontal ligament). The purpose of this study was to compare the healing of intrabony defects with and without the placement of decalcified freeze-dried bone allograft (DFDBA) in a nonsubmerged environment in humans. The most apical level of calculus on the root served as a histologic reference point to delineate root surfaces exposed to the oral environment and to measure new attachment apparatus and new component tissue formation. Free gingival grafts were placed over grafted and nongrafted defects to retard epithelial migration. Biopsies were obtained at 6 months and regeneration was evaluated histometrically. Data from 12 patients with 32 grafted and 25 nongrafted defects were submitted for statistical analysis. Results indicate that in nongrafted defects, a long junctional epithelium formed along the entire length of exposed root surfaces and often extended apical to the calculus reference notch. Free gingival grafts did not enhance regeneration of a new attachment apparatus, new cementum, new connective tissue, or new bone in nongrafted defects. The formation of a new attachment apparatus was observed when intrabony defects were grafted with DFDBA (x1.21 mm); significantly more new attachment apparatus (P less than .005), new cementum (P less than .005), new connective tissue (P less than .05), and new bone (P less than .0001) formed in intrabony defects grafted with DFDBA than in nongrafted defects. There was a greater chance for regeneration of a new attachment apparatus and component tissues in grafted defects than in nongrafted defects. New cellular cementum formed on old cementum and dentin but more often formed over both in the same defect). The periodontal ligament was more frequently oriented perpendicular to the root; there was greater loss in alveolar crest height in nongrafted than grafted defects (P less than .05); and extensive root resorption, ankylosis, and pulp death were not observed in grafted or nongrafted defects.
Abs tract. T hicke ned hyalin e tr ache al membra ne simila r to that which occurs with severa l respira to ry co nditions in man was seen in Rhe su s mo nkeys. Th e memb ran e was cosinophili c a nd up to 50.4 urn thic k. Freq uentl y eosino phils a nd ma st ce lls were seen in the trach ea l mucosa a nd submucos a. Us ing fluore scent microscop y, IgG, B 1C, B1A a nd a lbumin were identifi ed in the membran e. Electro n microscop y sho wed tha t the membra ne was co mposed of I8.8-nm co llage n-like fibr ils wit h occasional peri odicity. T he ca use of the thicke ned hyalin e tr acheal mem bran e could not be determ ined . T he cha nges pr oba bly represent a response to mild repe a ted or co nti nuou s trac hea l inj ury ow ing to a variety of causes. De linea tion of the ca use of this pr oce ss in non hu ma n primat es may hclp in the understan d ing of respirato ry diseases in man.Thicken in g of th e trach eal basem ent membran e occ ur s in a va riety o f human d iseases such as asth ma , chro nic b ron chit is, Loeffler's sy nd ro me a nd p ulmo nary allergic gra nu lo ma tosis [2-4, 6, II , 14]. In these d iseases it s pa thoge nes is a nd importan ce a re un kn own , but it may be a resp on se o f the tra chea to chro nic mu co sal injury. The th ickened membran e is co m posed o f hyal ine mat eri al a nd is ind uce d by a hype rsen siti vit y sta te [3]. Immunoglobul ins have been identifi ed in thi ck en ed br onchi al ba sem ent membranes [4, I I].Other ca uses o f trach eal ba sement membran e thi ck enin g a re endopa rasites, whi ch a re rep orted to produce hyper sen siti vity [7,13]. Vermin ou s pn eumonia in sea lion s [7] often is acco mp a n ied by a n eosi no philic hyalin e materi al adj acent to th e ba sement membran e o f th e trach ea a nd large br on chi . lnfrequentl y, hum an asthma has been a tt ributed to inh al ati on o f hou se mit es in du st , w h ich th en act a s a so urce o f allergen as d o non-li vin g materi al s [8].Snee zing a nd co ug hi ng a re associated with acariasis in O ld W orld prim at es[10] ; but no a lle rgic sy nd ro me o r tr ach eal basem ent thi ck en ing was rep o rt ed .Thi s paper describes t hicke ned tr ach eal basem ent membra nes in 90 Rh esu s monkeys.
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