TY - JOUR
T1 - Repair process of external root resorption subsequent to palatal expansion treatment
AU - Vardimon, A. D.
AU - Graber, T. M.
AU - Pitaru, S.
N1 - Funding Information:
This investigation was supported in part by gra.nts from the German Research Foundation (DFG-Va 70/I-1 and DFG-Schm 23212-1), the America~, Dental Association, and the Kenilworth Dental Research Foundation. JDepartment of Orthodontics, School or Dentistry, University of Bonn. Federal Republic of Germany. bAmerican Dental Association, tlealth Foundation Research Institute, Chicago, I11. CDepartment of Oral Biology, School of Dental Medicine, Tel Aviv University. Tel Aviv, Israel. eDcpartment of Orthodontics, School of Dental Medicine, Tel Aviv University. Cop)fight 9 1993 by the American Association of Orthodontists. 0889-5406193151.00 + 0.10 811133055
PY - 1993/2
Y1 - 1993/2
N2 - The repair process of external root resorption (ERR) and the role of retention mechanics in enhancing ERR repair were studied on eight Macaca fascicularis monkeys that were divided equally into short-and long-term groups. Six monkeys received palatal expansion appiances, and two received sham appliances. The short-term group received active treatment. The long-term group received additional retention (4 months) and relapse (2 months) treatment periods with biweekly injections of individual vital dye per phase, i.e., procion red H-8B and violet H-3R (80 mg/kg B.W.), respectively. Histomorphologic examinations included scanning electron microscopy, light, and ultraviolet microscopy. The short-term group demonstrated penetrated resorption with pulp exposure at sites with initial deficiency of the protecting odontoblastic layer (apacal zone, nutrition canal). The long-term group showed two forms of ERR repair: (1) Nonfunctional retarded repair cementum, comprised of overlapped incremental lines and deprived of extrinsic fibers, was delineated in severe pulp exposure. The pulp/dentin complex showed intense incorporation of procions dye in the dentinal tubuli, conceivably related to a defense response in the form of sclerotic dentin. (2) Functional rapid repair cementum, comprised of discriminated incremental lines mainly of mixed cellular cementum, with a consistent pattern of five sequential phases: the lag phase (14 to 28 days), the incipient phase (14 days), the peak phase (14 to 28 days), the steady phase (42 to 56 days) and the retreating phase (70 days). Sharpey's fibers at functional ERR sites were scarce, never emerging from the dentinocemental junction, and not developing into principal fibers. The pulp/dentin complex showed an increase in pulp stones but not formation of teriary dentin. The apical area responded by hypercementosis in the form of apical occlusion and a displaced pulp canal. The application of a fixed retention device is recommended in light of accelerated apposition of repair cementum during the retention period. However, increased formation of Sharpey's fibers during the relapse period might suggest a restricted duration in splinting therapy.
AB - The repair process of external root resorption (ERR) and the role of retention mechanics in enhancing ERR repair were studied on eight Macaca fascicularis monkeys that were divided equally into short-and long-term groups. Six monkeys received palatal expansion appiances, and two received sham appliances. The short-term group received active treatment. The long-term group received additional retention (4 months) and relapse (2 months) treatment periods with biweekly injections of individual vital dye per phase, i.e., procion red H-8B and violet H-3R (80 mg/kg B.W.), respectively. Histomorphologic examinations included scanning electron microscopy, light, and ultraviolet microscopy. The short-term group demonstrated penetrated resorption with pulp exposure at sites with initial deficiency of the protecting odontoblastic layer (apacal zone, nutrition canal). The long-term group showed two forms of ERR repair: (1) Nonfunctional retarded repair cementum, comprised of overlapped incremental lines and deprived of extrinsic fibers, was delineated in severe pulp exposure. The pulp/dentin complex showed intense incorporation of procions dye in the dentinal tubuli, conceivably related to a defense response in the form of sclerotic dentin. (2) Functional rapid repair cementum, comprised of discriminated incremental lines mainly of mixed cellular cementum, with a consistent pattern of five sequential phases: the lag phase (14 to 28 days), the incipient phase (14 days), the peak phase (14 to 28 days), the steady phase (42 to 56 days) and the retreating phase (70 days). Sharpey's fibers at functional ERR sites were scarce, never emerging from the dentinocemental junction, and not developing into principal fibers. The pulp/dentin complex showed an increase in pulp stones but not formation of teriary dentin. The apical area responded by hypercementosis in the form of apical occlusion and a displaced pulp canal. The application of a fixed retention device is recommended in light of accelerated apposition of repair cementum during the retention period. However, increased formation of Sharpey's fibers during the relapse period might suggest a restricted duration in splinting therapy.
UR - http://www.scopus.com/inward/record.url?scp=0027548470&partnerID=8YFLogxK
U2 - 10.1016/S0889-5406(05)81761-5
DO - 10.1016/S0889-5406(05)81761-5
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AN - SCOPUS:0027548470
SN - 0889-5406
VL - 103
SP - 120
EP - 130
JO - American Journal of Orthodontics and Dentofacial Orthopedics
JF - American Journal of Orthodontics and Dentofacial Orthopedics
IS - 2
ER -