Late-forming supernumerary teeth: A case series.

The aim of this case series was to illustrate the development of late-forming supernumerary teeth (LFST) and highlight the implications for orthodontic treatment. There are limited studies relating to the aetiology, prevalence and treatment of LFST and the cases presented here demonstrate the management of LFST within a tertiary care centre. Five cases are presented, which show various presentations and chronological ages in the development of LFST. This case series emphasises the significance of maintaining a low threshold for suspecting LFST in patients where supernumerary teeth have previously been identified. It also highlights the importance of regular clinical and radiographic reviews. Timely identification can help prevent complications and optimise treatment outcomes.

Evidence that ectopic upper third molars can result in upper second molar impactions: A case series.

INTRODUCTION: The aim of these four case reports was to illustrate the presence of potential upper second molar impactions associated with ectopic third molars and to highlight that some cases have an atypical radiographic presentation. CASE PRESENTATIONS: Four patients (age range = 7-12 years) with various malocclusions presented to the paediatric and orthodontic departments for treatment to address their presenting complaints. Incidental radiographic findings demonstrated potentially impacted upper second molars associated with ectopic third molars. In all of these cases, a joint paediatric-orthodontic approach was adopted to address their dental health, prevent upper second molar impaction and to treat their malocclusion. DISCUSSION: Careful and systematic review of radiographic imaging was necessary in order to correctly diagnose these cases. These cases demonstrated that it was not always simple to determine impactions, particularly as identification of third molar crypts can be difficult. On occasion, sequential radiographical monitoring is advocated, particularly in patients in the mixed dentition; however, clinicians must be mindful of the risks of ionising radiation as it is not routine practice to irradiate a patient multiple times. CONCLUSION: The series of cases highlights the need for a systematic assessment of OPTs to identify ectopic upper third molars. The input from radiologists is invaluable and if necessary, supplemental three-dimensional cone-beam computed tomography can be performed.

Cooperativity of Cdk4R24C and Ras in melanoma development.

The importance of the CDK4 protein in human cancer first became evident following the identification of a germ line mutation in the Cdk4 locus that predisposes humans to melanoma. This mutation results in substitution of arginine with cysteine at position 24 (R24C). In an earlier study, we introduced the R24C mutation into the Cdk4 locus of mice using Cre-loxP-mediated "knock-in" technology and observed a very low incidence of spontaneous melanomas in Cdk4(R24C/R24C) mice. This suggested that additional oncogenic mutations might be required for development of melanomas. Here we report an increased incidence of spontaneous cutaneous melanoma in mice expressing the oncogene HRAS(G12V) in melanocytes on a Cdk4(R24C) background. Treatment of Tyr-HRas:Cdk4(R24C/R24C) mice with the carcinogen, DMBA/TPA resulted in a further increase in the number of nevi and melanomas developed when compared with Tyr-HRas:Cdk4(+/+) mice. In summary, in Tyr-HRas:Cdk4(R24C/R24C) mice, we observed that activated CDK4 cooperates with the oncogenic HRAS(G12V) protein to increase the susceptibility of melanoma development in vivo.