Vertical root fractures lead to advanced periodontal breakdown with deep periodontal pockets and vertical bone defects. The purpose of this study is to evaluate clinically the periodontal healing of root fracture treatment using adhesive resin cement. In 22 patients, 23 teeth with vertical root fractures were treated with 4-META/MMA-TBB resin cement. Eleven fractured roots were bonded through the root canal (group A) and 12 fractured roots were bonded extra-orally and replanted (group B). All teeth were then restored with full cast crowns (n=20) or coping (n=3). Mean probing depth was 6.6 mm at pre-treatment and 4.4 mm 6 months after the treatment in group A, and 7.4 mm and 4.6 mm, respectively, in group B. Bleeding scores were 100% at pre-treatment and 36.4% after 6 months in group A and 91.7% and 8.3%, respectively in group B. Radiographic bone level was 56.8% at pretreatment and 59.1% after 6 months in group A, and 18.8% and 29.2%, respectively, in group B. Two roots of group A and three roots of group B were extracted due to refracture, deterioration of periodontal inflammation, mobility, and luxation. The remaining roots (n=18) presented no discomfort to the patients and there was no deterioration of periodontal conditions over a mean period of 33 months (range 14-74 months) in group A and over a mean period of 22 months (range 6-48 months) in group B. There was no ankylosed teeth nor was any root resorption detected. The results suggested that the treatment of vertical root fracture using 4-META/MMA-TBB resin has good prognostic possibilities.

These case reports describe a new treatment method for complete vertical root fractures. This method is composed of two steps. First, the fractured tooth is intentionally extracted atraumatically, and then the separated fragments are bonded with an adhesive resin cement. The restored tooth is replanted by rotating approximately 180 degrees into the original socket and fixing with an orthodontic wire. For both cases reported here, bone regeneration was observed at the 3-year follow-up. Since this modality adopts the respective advantages of both intentional replantation and adhesive treatment, it might be the treatment of choice in cases of vertical root fracture.

For over a century, zinc phosphate cement (ZPC) has been conventionally used as a luting agent, with its long-term longitudinal longevity being reported in several studies. [1][2][3][4][5][6][7][8] However, this cement adheres to teeth and castings only by mechanical interlocking. Glass ionomer cement and carboxylate cement were developed for physicochemical bonding around 1970 9,10 ; however, as their adhesive properties were similar to those of ZPC, ZPC continued to be used clinically. 11 In the early 1950s, insoluble dental resins were developed as adhesive cements to prevent secondary caries and dislodgement over time. However, the adhesion of resin cements to tooth structure was limited until Buonocore 12 reported the acid-etching technique in 1955. In 1963, Masuhara and Kojima reported that methyl methacrylate (MMA) polymerized with the initiator tributylborane (TBB) bonded well to wet elephant tusk ivory and teeth 13 without acidic adhesive monomers or the acid etching technique. This MMA/TBB autopolymerizing resin was first marketed as Orthomite (Mochida Pharmaceutical Co Ltd) in 1971 for the direct bonding of This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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