Prognosis of non-vital incisors after apexification using bioceramics: a retrospective study.

PURPOSE: To evaluate the outcome of apexification using bioceramics in immature permanent teeth, and to study the factors influencing treatment outcome and frequency of spontaneous cervical root fractures. METHODS: Forty-six children with 51 non-vital permanent incisors treated with a bioceramic apical plug were included. Mean age at pulp necrosis was 9.8 (SD 2.2) years and mean follow-up time was 3.3 (SD 2.4) years. Data were extracted from dental records and included stage of root development, presence of external root resorptions, clinical signs of infection, size of periapical lesion, type and placement of bioceramic plug, and spontaneous root fracture. Treatment outcome was assessed using periapical index (PAI-score) and presence of clinical symptoms. The statistical analyses were conducted using IBM SPSS Statistics for Windows, version 28 (IBM Corp., Armonk, N.Y., USA). Data were cross-tabulated and tested with chi-square statistic. RESULTS: Biodentine™ was used as apical plug in 78.4% of the teeth and MTA in 21.6%. Complete healing or signs of healing was reported in 86.3% of the teeth, whilst seven teeth (13.7%) were non-healed. All non-healed teeth had preoperative clinical signs of infection. No difference was found in stage of root development, presence of root resorption, and type and placement of bioceramic plug in healed and non-healed teeth (p > 0.05). Five teeth (9.8%) exhibited root fracture 1-6 years after treatment and all had very immature root development. Type of bioceramic or external root resorption was not associated with spontaneous root fracture. CONCLUSION: Apexification using bioceramics showed favourable prognosis in immature permanent teeth. Very immature teeth were at risk of root fracture after apexification with bioceramics.

Extraction of first permanent molars severely affected by molar incisor hypomineralisation: a retrospective audit.

AIM: The aim of this study was to evaluate possible spontaneous space closure after extraction of first permanent molars in children and their eventual need for orthodontic treatment. METHODS: Twenty-seven children with at least one first permanent molar planned for extraction were enrolled in the study. The children were referred to the Department of Paediatric Dentistry, University of Oslo, between 2009 and 2017. All extracted teeth were severely affected by Molar Incisor Hypomineralisation and/or caries. The children and their parents had consented to extraction and follow-up. Data were analysed with SPSS 26. RESULTS: The age of the children was between 5.5 and 12.1 years (mean 8.7) at extraction. The mean follow-up time was 3.2 years (range 1.1-6.3). Sixteen children (59.3%) had all four molars extracted, five (18.5%) had three, five had two and one had one molar extracted. In the maxilla, the second permanent molar had erupted in the place of the first molar in all the children, and none of them needed orthodontic space closure. In the mandible, eight children (29.6%) needed orthodontic treatment to close the spaces after extraction. In three children, the second molar was not yet erupted and treatment need was not settled. CONCLUSION: Extraction of severely affected first permanent molars before the eruption of the second molar is a treatment option causing little additional treatment in the majority of cases.

Effects of antibiotics on the developing enamel in neonatal mice.

PURPOSE: Identifying factors causing Molar-Incisor Hypomineralization (MIH) is an ongoing challenge. Preterm infants, routinely treated with antibiotics in cases of suspected sepsis, are more commonly affected by dental developmental defects. This study aimed to investigate the effects of gentamycin and ampicillin on the developing enamel in neonatal CD-1 mice in vivo. METHODS: Neonatal mice were randomized into a study (n = 36) and a control (n = 35) group. Antibiotics were injected intravenously for 4 days. All mice were sacrificed after 15-18 days. Micro-CT was used to analyse the mineral density (MD) of the enamel and the proportion of the enamel object volume (vol%) in first molars and incisors. RESULTS: We demonstrated a significantly lower vol% enamel in the maxillary (30.9% vs. 32.7%; p = 0.004) and mandibular (32.5% vs. 34.6%; p = 0.015) molars in the study group than in the controls. The incisors were divided into segments upon analysis. We demonstrated both lower vol% and lower MD of the enamel in most segments in treated individuals compared to controls (p < 0.05). CONCLUSION: The reduced MD and vol% in the molars and incisors are likely to have been caused by the antibiotics given during tooth development. The presented analysis of teeth in neonatal mice with micro-CT could be a valid model for further research on dental developmental defects.

Knowledge, experience and perception regarding molar incisor hypomineralisation (MIH) among dentists and dental hygienists in Oslo, Norway.

AIM: The aim of this study is to gather baseline information on knowledge, perceptions, clinical experience and treatment options regarding MIH among dental care providers in Oslo, Norway, before a larger epidemiological study. METHODS: An electronic questionnaire was distributed to dentists (n = 88) and dental hygienists (n = 47) working in the Public Dental Service (PDS) in Oslo. The questionnaire consisted of five sections related to sociodemographic, clinical experience, perceptions, clinical management and preferences for further training. Descriptive statistics with chi-squared test was used, and level of statistical significance was set to 5%. RESULTS: Replies were obtained from 74.1% (n = 100) after two reminders. All respondents encountered MIH in their practice. The respondents' perception of the prevalence of MIH in Oslo varied. The majority felt confident when diagnosing MIH (86%). The clinicians qualified in the last 10 years felt more confident than those who had qualified earlier (p = 0.016). Most were self-confident when treating these patients (68.3%), however, nearly all (88%) agreed that MIH was a clinical problem. The clinician's treatment of MIH varied. Difficulties achieving adequate local anaesthetic (71.4%) and the child's behavioural problems (84.1%) were treatment barriers for the dentists. Approximately two thirds (69%) would like further training, in particular on the aetiology (70%), diagnosis (57%) and treatment (77%) of the developmental disorder. CONCLUSION: All clinicians were familiar with the diagnosis of MIH and experienced the condition to be a clinical problem. Continuing education on aetiology, diagnosis and treatment of MIH is requested by dental health personnel.

Nerve growth factor receptor (p75 NTR) and pattern of invasion predict poor prognosis in oral squamous cell carcinoma.

AIMS: To evaluate the expression of p75 neurotrophin receptor (p75(NTR)) in oral squamous cell carcinoma (OSCC). The results were related to tumour node metastasis (TNM) stage, World Health Organization (WHO) grade, invasive front grading (IFG) and prognosis. METHODS AND RESULTS: Immunohistochemically, the expression of p75(NTR) was assessed in 53 T1-T2 OSCCs. Clinical data were recorded prospectively. The end-point was disease-free survival. All tumours expressed p75(NTR), and this expression, both in central/superficial tumour areas and at the invasive front, was associated with poor prognosis (P = 0.03 and P = 0.02) (log rank test). Tumours with marked cellular dissociation (IFG parameter) had more recurrences than tumours with collective tumour cell invasion (P = 0.03). In tumours showing both p75(NTR) at the invasive front and marked tumour cell dissociation, the average risk of recurrence was increased about 17 times (Cox regression analysis) compared with tumours with low p75(NTR) expression and collective invasion. Traditional prognostic systems were of no prognostic significance. CONCLUSION: p75(NTR) was expressed in all OSCCs. p75(NTR) expression and the pattern of invasion were significantly associated with a poor prognosis in OSCCs, and both were better prognostic factors than traditional prognostic parameters. The combination of p75(NTR) expression and the pattern of invasion strongly increased precision in the identification of tumours with poor disease-free survival.