| Trauma to anterior teeth especially the crown fracture is a frequent occurrence. Classical treatments include fragment reattachment, composite resin build-up, veneer or crown. The fragment reattachment is more concerned by both patients and dentists because of its aesthetic, simple and cost-effective advantage.Clinical dentist who adopt this treatment are often concerned with several questions, like the strength of the fragment reattachment compared with composite resin build-up, the selection of adhesive materials, the effect of retention form, and the clinical effect.This study aims directly to the above questions. Firstly review the literature about the fragment reattachment published in the last 20 years. Secondly establish the fractured model successfully for the in vitro study; Compare the shear bond strength of the fragment reattachment and the resin build-up; Compare the shear bond strength of the anterior teeth reattached by two adhesive materials and by three retention forms. Thirdly study the preliminary clinical effect of the fragment reattachment. Part One The literature review of fragment reattachment in recent 20 yearsMethods A search was conducted to identify all the articles published in English and Chinese related to fragment reattachment in recent 20 years. Then the articles were divided to the two endodontic residents who read them and assigned a level of evidence (LOE) for each article independently. And the professor read the articles the two had different opinions and decided them.Result Based on our inclusion and exclusion criteria, we found 90 English and 82 Chinese related articles, both of which increased in the recent 20 years. In 153 clinical articles, 71 were LOE-5, while 77 were LOE-4, 4 were LOE-3, 1 were LOE-2, 0 were LOE-1.Conclusion The fragment reattachment was more and more concerned in the recent 20 years. But there are few high level articles.Part Two In vitro study of tooth fragment reattachment1 Establishment of the crown fractured modelMethods Sixty intact maxillary central incisors were embedded in self-cure acrylic resins by leaving one third of the incisal anatomical crowns exposed. Then the specimens were submitted to an axial compression test in a universal testing machine. Put the spade on the buccal surface of the tooth with a speed of 1 mm/ min until tooth fractured. Record the strength when the tooth fractured and the number of the fragments. The tooth fractured into two pieces was considered to be successful. Results The shear bond strength (SBS) ranged from 623.1N to 1184N with the mean and standard of 855.94±147.43N. Among 60 teeth, 43(71.67%) fractured into two fragments were successful.Conclusion The anterior fractured model were successfully established.2 Comparison of the shear bond strength of anterior teeth restored by fragment reattachment and the resin build-upMethods Thirty-six anterior crown fractured modes were divided into two groups randomly, with 18 in each group. Group A was reattached by the original fragment, while group B rebuilt-up by the composite resin. Then the specimens were again submitted to an axial compression test in a universal testing machine in 24 hours. The spade was put on the buccal surface of the tooth with a speed of 1 mm/ min and a maximum limit of 10 kN until tooth fractured.Results The mean shear bond strength of group B is not statistically higher than group A (t = 1.190, P = 0.242).Conclusion The shear bond strength of the composite resin build-up were not better than the fragment reattachment.3 The effect of adhesive materials on fragment reattachmentMethods Forty anterior crown fractured modes were divided into two groups randomly, with 20 in each group. Group A was reattached by CSE and AP-X, while group B reattached by CTB and AP-X. Then the specimens were submitted to an axial compression test in a universal testing machine. The spade was put on the buccal surface of the tooth with a speed of 1 mm/ min and a maximum limit of 10 kN until tooth fractured.Results The mean shear bond strength of group A is statistically higher than group B (t = 3.17, P = 0.003).Conclusion The shear bond strength of two step self-etch adhesive was higher than one-step one for the reattachment of anterior fractured teeth.4 The effect of retention forms on fragment reattachmentMethods Forty anterior crown fractured mode were divided into four groups randomly. Group A was simply reattached; group B bevel; group C internal dentinal groove; group D overcontour. Then the specimens were submitted to an axial compression test in a universal testing machine. The spade was put on the buccal surface of the tooth with a speed of 1 mm/ min and a maximum limit of 1800N until tooth fractured.Results The mean shear bond strength of the restored four groups were: group A(211.31±59.30)N, group B(300.29±89.81)N, group C(349.24±86.84)N, group D(327.03±85.85)N. The strength of group B,C,D were statistically higher than group A(P < 0.05), but were not statistically different within them(P > 0.05).Conclusion The retention forms can strengthen the effect of tooth fragment reattachment. Part Three Clinical research of fragment reattachmentMethods Eleven crown fractured anterior teeth were selected. After pulp dealt, retention form prepared, the teeth were reattached by the adhesive SE Bond and the composite resin AP-X. The restorations were clinically evaluated immediately, afer 3 and 6 months by the patients and the doctors.Results Patients'evaluation: all the patients were satisfied after the treatment. Afer 3 months, the number of the satisfied, less satisfied and the dissatisfied were 8, 1, and 1 respectively. Afer 6 months, the number of the satisfied, less satisfied and the dissatisfied were 7, 2, and 0 respectively. Doctor's evaluation: after the treatment, the number of the satisfied less satisfied and the unsatisfied teeth were: 10, 1 and 0 respectively. Afer 3month, the number of the satisfied, less satisfied and the unsatisfied teeth were 9, 1, and 1 respectively. Afer 6month the number of the satisfied less satisfied and the unsatisfied teeth were 8, 2, and 0 respectively.Conclusion Tooth fragment reattachment presents a good short-term effect after 6 months study. |
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