Assessment of Periodontal Biotype in a Young Chinese Population using Different Measurement Methods.

Periodontal biotype is used to describe the morphological characteristics of periodontal tissues and is closely related to periodontal health and prognosis of many dental treatments. This study was undertaken to explore the periodontal biotype distribution in a young Chinese population and to evaluate the accuracy of different methods for gingival thickness (GT) measurement. A total of 372 teeth from 31 periodontally healthy subjects were included. GT was measured simultaneously by probe transparency, transgingival probing and cone-beam computed tomography (CBCT). Some other anatomic parameters, including crown width/crown length ratio, attached gingival width, labial bone thickness and papilla volume were recorded for periodontal biotype classification. As found by probe transparency, the gingivae of 222 teeth (59.68%) were thick, while those of 150 teeth (40.32%) were thin. The mean GT of included subjects was 1.03 ± 0.31 mm as measured by transgingival probing and 1.03 ± 0.24 mm as measured by CBCT. Four groups were identified by cluster analysis. Thick-flap biotype, average-scalloped biotype, average-flap biotype and thin-scalloped biotype comprised 137 teeth (36.83%), 96 teeth (25.81%), 39 teeth (10.48%) and 100 teeth (26.88%), respectively. These results demonstrate that the most common periodontal biotype in this young Chinese population was the thick-flap type with low aesthetic risk.

Complication After Extraction of Natal Teeth with Continued Growth of a Dental Papilla.

The purposes of this case report were to describe a growing two-cm gingival mass that developed after natal teeth were extracted in a four-month-old female patient, present a review of the literature on the growth of a gingival mass after the extraction of natal teeth, and illustrate the clinical and histological features that differentiate this condition from other types of gingival masses in infants. Histological examination of the excised mass revealed that it contained tooth-like hard tissue (regular and irregular dentin) that intermingled with bone, dental pulp, and fibrous tissue. We found eight cases from 1962 to 2009 in which a soft-tissue mass with dentin-like hard tissue or a tooth-like structure had developed after the extraction of natal teeth. Based on clinical and histological findings, we deduced that the mass was the result of abnormal growth of a residual dental papilla, including mesenchymal stem cells. Consequently, dentists, obstetricians, gynecologists, and pediatricians should be aware of this potential complication and observe caution before they extract natal teeth.

[Recombinant study of mouse enamel organ and dental papilla by renal transplantation: effects of discrepancy in number of these two components].

Interactions between the epithelium and mesenchyme were very important in tooth development. When these relationships changed qualitatively or quantitatively, developmental tooth abnormalities or odontogenic lesions might develop. In order to clarify this hypothesis, we examined the effects of discrepancy in the number of enamel organs and dental papilla on histo- and morpho-differentiation of the recombinants by renal subcapsular transplantation. Five kinds of recombinants were prepared from the enamel organs(E) and dental papilla (M) of the mandibular first molars of 17-gestational-day C3H mice: group 1 (E/M = 2/6), group 2(E/M = 3/5), group 3(E/M = 4/4), group 4 (E/M = 5/3) and group 5 (E/M = 6/2). After 28 days of transplantation, all the grafts were harvested and examined roentogenographically and histopathologically. All the grafts developed into teeth. The teeth of groups 1 and 5 were independent from each other and the teeth of groups 2, 3 and 4 fused with each other by dentin. The number and size of the teeth depend on the number of M and the differences between E and M of the recombinants, respectively. The smaller the difference, smaller was the teeth size. The cysts lined by the keratinizing squamous epithelium developed from E-rich recombinants. These could be comparative to the compound odontoma, fused teeth and odontogenic keratocyst of the human being respectively. It might be speculated that the histogenesis of these lesions might be related to the quantitative change in the epithelial-mesenchymal interactions of odontogenesis.

Calcification of the dental papilla. A rare finding.

An interesting case is reported, of calcification of the dental papilla. As yet, little is known about this asymptomatic calcification, which constitutes a rare radiographic finding, deforming the root of a vital tooth, generally a lower premolar or canine.