الفهرس 
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Abstract
SUMMARY AND CONCLUSIONS
The aim of this study was to compare between MTA and BioAggregate repairing materials regarding: Tissue reaction after perforation repair and bonding to dentine in perforation site. The study will include radiographic and histologic changes. The study consisted of two parts, animal and push-out test. The animal study was performed for radiographic and histopathologic evaluation of the treatment outcomes over 3 month’s evaluation period. The total of 72 teeth from 6 healthy adult dogs were selected, both sides of mandibular premolars P2, P3 and P4and mandibular first molar. Also maxillary premolars P2, P3 selected from 6 dogs (12 teeth / dog).
72 teeth were divided into three main equal groups according to post treatment evaluation periods as following: GI; One- week time period (24 teeth). GII; One-month time period (24 teeth).GIII; Three- month time period (24 teeth).Each group was further subdivided into 4 subgroups: 2 experimental and 2 control subgroups as following: Subgroup (A): (MTA subgroup).Subgroup (B): (BioAggregate subgroup). Subgroup (C): (Positive control subgroup). Subgroup (D): (Negative control subgroup). Each subgroup was both radiographically and histopathologically evaluated.
After anesthesia the teeth were instrumented and obturated. In experimental and positive control samples the teeth were perforated in the center of the pulp chamber floor. The access cavity of all experimental and positive control teeth was left open for saliva contamination for 4 weeks (infection period). After the infection period the dog was reanesthesized and the radiographs were taken to confirm the formation of furcal lesions (preoperative radiographs).Then the perforation sites were curated to remove debris and inflamed tissues cleaned with saline and dried. To repair perforations two different cements were used as:
Subgroup (A): treated with MTA. Subgroup (B): treated with BioAggregate. Subgroup(C): positive control samples. Then the animals were returned to the animal house in the Surgery, Anesthesiology and Radiology department Cairo University and left for follow up according to the post treatment evaluation periods. In the end of each post treatment (experimental) period the animal was reanesthesized and the radiographs were exposed as follow up radiographs (postoperative radiographs).In this study the data were evaluated radiographically and histologically. Radiographic evaluation: Periapical preoperative radiograph after perforation repair compared with follow up radiographs according to post treatment evaluation periods using Image J analysis software and Turbo-Reg plug in. Bone loss was measured in each subgroup; data were collected and statistically analyzed.
Histologic evaluation: Blocks were decalcified and sectioned and examined under microscope, the following criteria were evaluated: I-Inflammatory tissue reaction (inflammatory cell count).II-Epithelial proliferation: Score (0): absence of epithelial proliferation. Score (1): presence of epithelial proliferation. III- Hard tissue formation: Score (0): absence of new hard tissue. Score (1): presence of new hard tissue. Then all data obtained subjected to statistical analysis.
Results: Radiographic evaluation showed no significant difference between experimental MTA, BioAggregate and Positive control in one-week time. Significant difference was seen at one-month and three-month’s time periods where radiolucency size decreased in MTA and BioAggregate and increased in positive control. Histological evaluation was done on inflammatory cell count.
At one- week time period there was no statistical significant difference between MTA, BioAggregate and positive control, all showed highest inflammatory cell count.
Significant difference was found at one-month and three-month time periods where the cell counts were decreased in MTA and BioAggregate and increased in positive control.
Regarding epithelial proliferation all subgroups showed signs of epithelial proliferation without significant difference between them at one-week period. After one-month and three-month time periods the difference was found where decreased in MTA and BioAggregate and increased in positive control.
As regard to new hard tissue formation, in one-week period there was a slight tissue deposition in little samples and healing not clear at this interval time. At one-month and three-month periods the evidence of hard tissue was noticed and no significant difference was found between MTA and BioAggregate both found highest deposition of hard tissue and furcation repair. Positive control was significantly lower regarding hard tissue deposition, because there was no new hard tissue formation.
In Push out test 40 extracted mandibular molars were selected, roots were amputated 3mm apical to furcation teeth were decoronated 3mm above the. Perforation holes were made between the canal orifices in apical direction with almost 1mm diameter. 40 molars were divided into two equal groups each of 20 teeth:
GI (MTA group): teeth repaired with MTA.
GII (BioAggregate group): teeth repaired with BioAggregate
To evaluate the bonding in perforation site push-out bond strength test was used by using the Universal testing machine. The results of this part of study showed that, statistical analysis showed no significant difference between mean push-out bond strength of two materials at P ≤ 0.05.BioAggregate showed statistically significantly higher mean push out bond strength (10.9 ±1.8) than MTA (6.2 ± 1.8).
Conclusions:
1- Furcation perforation has poor prognosis if the perforation site is not immediately repaired.
2-Both tested materials MTA and BioAggregateare excellent materials for furcation repair.
3-It seems that the process of healing of bone in furcation perforation needs long periods of time.
Recommendations:
1 – Longer follow up period is needed for evaluate healing of furcation perforation.
2- More investigations on immunological and cellular components of furcation perforation repair are needed