Cemental Tear in an Autotransplanted Tooth That Had Been Functioning for 15 Years.

INTRODUCTION: Cemental tears have been described as specific types of root surface fractures that are seen infrequently but can cause rapid collapse of the periodontal tissue. However, to the best of the authors' knowledge, cases of cemental tears in autotransplanted teeth and their recovery by autotransplantation have not been reported previously. This case report presents the clinical and histopathologic features of a rare case of a cemental tear that occurred on an autotransplanted tooth. This meant a total long-term treatment course of 20 years involving two separate treatment procedures. CASE PRESENTATION: In 1995, the mandibular left second molar of a 40-year-old woman was extracted, and autogenous tooth transplantation was performed simultaneously using a third molar from the same side. Good clinical and radiologic progress was observed for >10 years after tooth transplantation. After discovery of a vertical bone defect in the distal area in 2006, conservative periodontal treatment was conducted on the diseased periodontal pocket over the course of several years. In 2010, autogenous tooth transplantation and a subsequent histopathologic examination of the extracted tooth were performed. After recovery treatment, a 5-year follow-up examination provided good results. CONCLUSIONS: This case report concerns the suspected contributing factors of cemental tears and the recovery treatment. When cemental tears are suspected after radiographic and other clinical examinations, interventional surgical treatment should be performed immediately. When autogenous tooth transplantation is performed, following careful consideration of the advantages and disadvantages of appropriate treatment and proper selection, continuous monitoring should be a prerequisite because of the possible occurrence of cemental tear.

Clinical and Histologic Aspects of Cervical Cemental Tear as a Risk for Periodontal Diseases.

INTRODUCTION: Cemental tear (CeT) has been classified as a specific type of root fracture. It can lead to rapid periodontal breakdown, and recently not many reports have focused on periodontal concerns. This case report presents macroscopy, light microscopy (LM), and scanning electron microscopy (SEM) observations of fragments of CeT. Progression of periodontal disease is discussed in terms of anatomic characteristics of the cementum. CASE PRESENTATION: CeT was observed at a maxillary right central incisor of an 83-year-old male. After clinical examination and initial treatment, surgical periodontal therapy was performed in association with fragment extirpation, apicoectomy, replantation, and simultaneous regenerative treatment. Extirpated torn fragments and granulation tissue masses were subsequently examined by LM and SEM. Bacterial colonies were observed in and around peripheral crevices of cemental fragments. CONCLUSIONS: Characteristics of cervical CeT are similar to common periodontitis features, such as rapid, periodic, sporadic, and site-specific advance, with occasional spiral pattern of pathologic pockets. In this case report, these features correspond to progression of bacterial pollution along the periphery of the overlapping scales of the cementum. In cases with such advanced periodontitis features, CeT should be discussed as a possible diagnosis. Optimum treatment should be more interventional, such as removal of degraded and torn cemental layers, when definite diagnosis is made by intrasurgical inspection.

A comparison of stress relaxation in temporary and permanent luting cements.

PURPOSE: The stress relaxation and compressive strength of resin, resin-modified glass ionomer, glass ionomer, polycarboxylate, and zinc oxide eugenol cements were measured to determine the characteristics of these materials after setting. METHODS: A total of 19 luting cements including 12 permanent cements and 7 temporary cements were used. Cylindrical cement specimens (10mm long and 6mm in diameter) were obtained by chemical setting or light curing. The specimens were stored for 24-36 h in water at 37°C and were then used for the stress relaxation and compression tests. The stress relaxation test was carried out using three constant cross-head speeds of 5, 50, and 100 mm/min. Upon reaching the preset dislocation of 0.5 mm, the cross-head movement was stopped, and the load was recorded for 60s. Fractional stress loss at 1s was calculated from the relaxation curves. The compressive strength and modulus were measured at a cross-head speed of 1mm/min. Data were analyzed with the Kruskal-Wallis test and Holm's test. RESULTS: A zinc oxide eugenol cement [TempBOND NX] exhibited the largest fractional stress loss. A resin cement [ResiCem] showed the largest compressive strength, while a glass ionomer cement [HY-BOND GLASIONOMER CX] showed the largest compressive modulus among all tested cements (p<0.05). CONCLUSION: The fractional stress loss could not be classified by the cement type. Two implant cements [Multilink Implant and IP Temp Cement] showed similar properties with permanent resin cements and temporary glass ionomer cements, respectively. Careful consideration of the choice of cement is necessary.

Comparison of the mechanical properties of 2 prosthetic mini-implants.

Two prosthetic mini-implants (MTI and MDI), which have very similar shapes, are widely used. In this investigation, the mechanical and physical properties of 2 prosthetic mini-implants were investigated. The flexural properties were measured with a universal testing machine. The surface image was observed by SEM with EDX. X-ray analyses were performed. The maximum strength and proportion limit for the different implants differed significantly (P <0.01); however, elastic modulus did not differ significantly (P >0.01). Although the surface of the MTI was smooth, the MDI had a rough surface. The elemental analysis detected titanium (Ti) in the MTI, and Ti, aluminum, and vanadium in the MDI. From the x-ray diffraction pattern, the MTI, which is composed of pure titanium, had a narrow, sharp Ti (syn) peak, whereas the corresponding peak for the MDI was small and broad. Although the 2 devices have similar shapes and dimensions, their surfaces and mechanical properties differ greatly. MTI is easy to remove and wrought in clinical use, and MDI is excellent in flexural properties compared with MTI. (Implant Dent 2004;13:251-256)