Can we predict orthodontic extraction patterns by using machine learning?

OBJECTIVE

To investigate the utility of machine learning (ML) in accurately predicting orthodontic extraction patterns in a heterogeneous population.

MATERIALS AND METHODS

The material of this retrospective study consisted of records of 366 patients treated with orthodontic extractions. The dataset was randomly split into training (70%) and test sets (30%) and was stratified according to race/ethnicity and gender. Fifty-five cephalometric and demographic input data were used to train and test multiple ML algorithms. The extraction patterns were labelled according to the previous treatment plan. Random Forest (RF), Logistic Regression (LR), and Support Vector Machine (SVM) algorithms were used to predict the patient's extraction patterns.

RESULTS

The highest class accuracy percentages were obtained for the upper and lower 1st premolars (U/L4s) (RF: 81.63%, LR: 63.27%, SVM: 63.27%) and upper 1st premolars only (U4s) extraction patterns (RF: 61.11%, LR: 72.22%, SVM: 72.22%). However, all methods revealed low class accuracy rates (<50%) for the upper 1st and lower 2nd premolars (U4/L5s), upper 2nd and lower 1st premolars (U5/L4s), and upper and lower 2nd premolars (U/L5s) extraction patterns. For the overall accuracy, RF yielded the highest percentage with 54.55%, followed by SVM with 52.73% and LR with 49.09%.

CONCLUSION

All tested supervised ML techniques yielded good accuracy in predicting U/L4s and U4s extraction patterns. However, they predicted poorly for the U4/L5s, U5/L4s, and U/L5s extraction patterns. Molar relationship, mandibular crowding, and overjet were found to be the most predictive indicators for determining extraction patterns.

A machine learning model for orthodontic extraction/non-extraction decision in a racially and ethnically diverse patient population

INTRODUCTION

The purpose of the present study was to create a machine learning (ML) algorithm with the ability to predict the extraction/non-extraction decision in a racially and ethnically diverse sample.

METHODS

Data was gathered from the records of 393 patients (200 non-extraction and 193 extraction) from a racially and ethnically diverse population. Four ML models (logistic regression [LR], random forest [RF], support vector machine [SVM], and neural network [NN]) were trained on a training set (70% of samples) and then tested on the remaining samples (30%). The accuracy and precision of the ML model predictions were calculated using the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. The proportion of correct extraction/non-extraction decisions was also calculated.

RESULTS

The LR, SVM, and NN models performed best, with an AUC of the ROC of 91.0%, 92.5%, and 92.3%, respectively. The overall proportion of correct decisions was 82%, 76%, 83%, and 81% for the LR, RF, SVM, and NN models, respectively. The features found to be most helpful to the ML algorithms in making their decisions were maxillary crowding/spacing, L1-NB (mm), U1-NA (mm), PFH:AFH, and SN-MP(̊), although many other features contributed significantly.

CONCLUSIONS

ML models can predict the extraction decision in a racially and ethnically diverse patient population with a high degree of accuracy and precision. Crowding, sagittal, and vertical characteristics all featured prominently in the hierarchy of components most influential to the ML decision-making process.

Self-reported pain or injury from equipment used on military deployment

BACKGROUND

Information about pain and injury from equipment on a particular deployment is not disaggregated in the literature; thus, the nature of the issue is unclear.

AIMS

To determine the prevalence of pain or injury during a particular deployment that military personnel attributed to equipment they used on this deployment; and to document the types of equipment they identified, the type of pain or injury and how they thought the pain or injury occurred.

METHODS

This paper analyses data from a deployment and health survey of Australian Defence Force personnel. The participants are 8932 personnel who deployed to Iraq and 6534 who deployed to Afghanistan. Participants indicated whether they experienced pain or injury from equipment they used on deployment and detailed their experiences in response to an open-ended question (n = 563).

RESULTS

Sixteen per cent of Iraq-deployed and 21% of Afghanistan-deployed participants reported pain or injury from equipment they used on deployment. Body armour was the most common equipment identified; however, a wide range of equipment was related to pain or injury. A new finding is that pain or injury related to armour was attributed to its wear in vehicles and during vehicle ingress or egress.

CONCLUSIONS

Knowledge of the nature of pain or injury related to equipment used on deployment may help inform improved designs and practices to reduce or prevent avoidable harm to serving personnel.

Prevalence of molar-incisor hypomineralization and other enamel defects and associated sociodemographic determinants in Indiana

BACKGROUND

The aim of this study was to determine the prevalence and severity of molar-incisor hypomineralization (MIH) in a cohort of school-aged children in Indiana.

METHODS

A calibrated examiner screened eligible school-aged children for MIH and other enamel defects. The authors used the integrated Modified Developmental Defects of Enamel Index and the European Academy of Pediatric Dentistry criteria to examine the permanent first molars, permanent incisors, and primary second molars. The authors used descriptive statistics, exact 95% confidence intervals, and χ² tests for analysis (α = 5%).

RESULTS

A total of 337 participants (mean [standard deviation] age, 9.1 (1.7) years; 52% 6 through 8 years; 66% non-Hispanic white) were examined. The prevalence estimate for MIH was 13% as opposed to a 52% prevalence estimate for any enamel defect (AED) of any of the index teeth. Living in an area with water fluoridation levels greater than 0.7 parts per million or being non-Hispanic black was significantly associated with higher prevalence of AED (P < .05) but not with the prevalence of MIH. Demarcated opacities were the most prevalent defects (43%), followed by atypical restorations (32%). Higher age and higher number of MIH-affected surfaces were associated with larger MIH defect extension (P < .05).

CONCLUSIONS

Nearly 1 in 6 children in Indiana had at least 1 permanent first molar with MIH. Water fluoridation levels and race or ethnicity were associated with the prevalence of AED but not with MIH prevalence.

PRACTICAL IMPLICATIONS

US dental practitioners should be cognizant that MIH is a common finding. Children with a high number of MIH-affected surfaces would benefit the most from early identification and management as the extension of the defects tends to worsen with age.

U.S. Pediatric Dentists' Perception of Molar Incisor Hypomineralization

Purpose: The purpose of this survey-based study was to target U.S. pediatric dentists in the Midwest region to determine their knowledge, perceptions, and clinical management strategies of molar incisor hypomineralization (MIH). Methods: After obtaining appropriate authorizations, all pediatric dentists identified by the American Academy of Pediatric Dentistry's 2016 to 2017 membership directory in the 12 Midwest states were invited to take part in the study. The questionnaire, adopted from previous studies, incorporated information of the participants' demographics and educational/clinical backgrounds and MIH-focused questions. Descriptive statistics and chi-square tests were used for analysis. An alpha level less than 0.05 was considered statistically significant. Results: A total of 251 out of 975 surveys were completed (26 percent). Nearly all participants were familiar with MIH. The majority reported the MIH prevalence to be less than 10 percent in their clinical practice (62 percent). Most respondents were either very confident (65 percent) or confident (34 percent) when diagnosing teeth with MIH. The most cited clinical challenge in managing MIH teeth was "long-term success of restorations" (79 percent). When analyzed individually, responses differed significantly for different demographics and educational characteristics of the respondents (P<0.05). Conclusion: MIH is generally well acknowledged by U.S. Midwest pediatric dentists, with differences related to their perceptions of the condition's prevalence as well as clinical and restorative management challenges.

Normal Tissue Complication Probability (NTCP) Modelling of Severe Acute Mucositis using a Novel Oral Mucosal Surface Organ at Risk

AIMS

A normal tissue complication probability (NTCP) model of severe acute mucositis would be highly useful to guide clinical decision making and inform radiotherapy planning. We aimed to improve upon our previous model by using a novel oral mucosal surface organ at risk (OAR) in place of an oral cavity OAR.

MATERIALS AND METHODS

Predictive models of severe acute mucositis were generated using radiotherapy dose to the oral cavity OAR or mucosal surface OAR and clinical data. Penalised logistic regression and random forest classification (RFC) models were generated for both OARs and compared. Internal validation was carried out with 100-iteration stratified shuffle split cross-validation, using multiple metrics to assess different aspects of model performance. Associations between treatment covariates and severe mucositis were explored using RFC feature importance.

RESULTS

Penalised logistic regression and RFC models using the oral cavity OAR performed at least as well as the models using mucosal surface OAR. Associations between dose metrics and severe mucositis were similar between the mucosal surface and oral cavity models. The volumes of oral cavity or mucosal surface receiving intermediate and high doses were most strongly associated with severe mucositis.

CONCLUSIONS

The simpler oral cavity OAR should be preferred over the mucosal surface OAR for NTCP modelling of severe mucositis. We recommend minimising the volume of mucosa receiving intermediate and high doses, where possible.

Current trends in pulp therapy: a survey analyzing pulpotomy techniques taught in pediatric dental residency programs

PURPOSE

The study's purpose was to survey directors of pediatric dental residency programs in order to evaluate the materials currently being taught and used for pulpotomy procedures for primary teeth in educational and clinical settings.

METHODS

A web-based survey was emailed to all graduate pediatric dental residency program directors in the United States.

RESULTS

Seventy one emails were sent to program directors, 47 responded but only 39 respondents (55%) were included in the study. Results suggested a slight decrease in utilization of formocresol 1:5 dilution (P<.01) and an increase in both ferric sulfate (P<.05) and mineral trioxide aggregate (MTA; P<.02) utilization for primary tooth pulpotomy procedures. The most common reasons for elimination of formocresol (18% of respondents) were systemic health concerns and carcinogenicity, in addition to evidence-based literature. Even though 25% of respondents have begun to use MTA for primary pulpotomy procedures, the most common reason for utilization of other medicaments over MTA was its higher cost.

CONCLUSIONS

With 82% of graduate pediatric dental residency programs still utilizing formocresol 1:5 dilution for pulpotomy procedures in primary teeth, there has been no major shift away from its clinical use, in spite of increased usage of newer medicaments over the last 5 years.

Effect on behavior of dental treatment rendered under conscious sedation and general anesthesia in pediatric patients

PURPOSE

The purpose of this study was to determine if there were differences in the amount of time it took to exhibit positive behavior following dental treatment under general anesthesia (GA) vs conscious sedation (CS).

METHODS

This retrospective study examined charts of a pediatric dental office between 1999 to 2003. Patients presenting before 36 months old for an initial exam who were diagnosed with early childhood caries were included in the study. Following the initial exam, the patients were treated under GA or CS. These patients were followed to determine their behavior at the 6-, 12-, and 18-month recoil appointments.

RESULTS

Thirty-nine patients who received treatment under GA were identified and 41 were treated under CS. The former were 3.9 times (P < .01) (P = .0057) more likely to exhibit positive behavior at the 6-month recall appointment. Although not statistically significant, a trend toward positive behavior was exhibited at the 12- and 18-month appointments.

CONCLUSION

Clinicians should consider future behavior, in addition to caries, when determining treatment modalities for children presenting to their office with dental caries.

Dental caries experience and association to risk indicators of remote rural populations

BACKGROUND

Dental caries continues to be the most common infectious disease of childhood; however, it is no longer pandemic, but endemic in specific sectors of populations. Therefore, it is important to identify and target patients at risk of developing caries in order to develop specific preventive measures.

AIM

This study aims to test dental caries risk indicators for significant associations with caries severity.

DESIGN

Five separate, small, isolated rural villages in Mexico with varying degrees of caries prevalence were selected for this observational study. A total of 248 children were examined. Risk indicators were assessed via questionnaire and water and salt fluoride analysis. Caries severity was measured by the International Caries Detection and Assessment System (ICDAS-I).

RESULTS

Prevalence of caries ranged from 95% to 100% for the five villages. Mean total DMFS (decayed, missing, or filled surfaces-permanent teeth) and dmfs (decayed, missing, or filled surfaces-primary teeth) scores ranged from 2.5 to 5.0 and from 11.3 to 16.9, respectively. Multivariable models showed age and drinking soda between meals to be significantly associated with DMFS, and drinking juice and being female were significantly associated with dmfs.

CONCLUSION

DMFS and dmfs were high in each village, significantly different between villages, and associated with specific risk indicators.

An evaluation of DNA yield, DNA quality and bite registration from a dental impression wafer

BACKGROUND

The authors determined the amount and quality of the DNA captured by a bite impression wafer and analyzed any inaccuracies in the impression wafer.

METHODS

The authors made bite registrations for subjects aged 7 to 12 years by using a dental impression wafer (Toothprints, Kerr, Orange, Calif.), obtained an oral rinse sample, took cheek cells by using buccal swabs and made an alginate impression to pour a stone model. They extracted and quantified the DNA from the dental impression wafer, mouthwash and buccal swabs by using the Quant-iT PicoGreen (Invitrogen, Carlsbad, Calif.) assay and a real-time polymerase chain reaction (RT-PCR) assay. They compared the stone models and imprints from the wafer.

RESULTS

The average amounts of DNA determined by using Quant-iT PicoGreen from the buccal swab, mouthwash and dental impression wafer samples were 113.61, 509.57 and 1.03 micrograms, respectively. The average amounts of DNA determined by using RT-PCR from the buccal swab, mouthwash and dental impression wafer samples were 11.5240, 22.2540 and 0.0279 mug, respectively. The bite registrations and stone models had an average of 14 percent of mismatches.

CONCLUSION

The dental impression wafers captured DNA but not in high quantities. They did not produce an accurate representation of the dentition.

CLINICAL IMPLICATIONS

The dental impression wafers captured enough DNA to permit amplification. The accuracy of the bite registration was not sufficient for identification purposes. Therefore, dental impression wafers may be useful only as a reservoir for DNA.

Public Assistance Orthodontic Treatment Needs: A Report from the State of Indiana

OBJECTIVE

To determine how many of the orthodontic cases covered by Indiana Medicaid between 1999-2001 would be classified pretreatment as having a malocclusion severe enough to warrant treatment.

METHODS

Six examiners were trained and then paired together to examine 249 patient orthodontic case records, consisting either of pre-treatment photographs only, pre-treatment models only, or both pre-treatment models and photos. The examiners applied the Index of Orthodontic Treatment Needs (IOTN) to assign each case a Grade of One to Five, with Grade One representing Ideal Occlusion and Grade Five being Extreme Malocclusion. When two examiners within a pair could not agree, a third examiner reviewed the case record to determine agreement.

RESULTS

Of the 249 patient cases examined, 9 were not gradable. In the cases where only pretreatment models were available (n=157), 10% received a Grade of One or Two (Ideal Occlusion or Mild Malocclusion, respectively). Among the cases in which both pretreatment models and photos were available (n=46), 44% of the photos were graded One or Two, while only 2% of the models were graded as One or Two. In the cases where only pretreatment photographs were available (n=37), 27% of cases were Grade One or Two.

CONCLUSION

While several of the cases (11%) submitted during the time period of 1999 to 2001 to the Indiana State Medicaid Division for reimbursement were rated as having Ideal Occlusions or Mild Malocclusions, the vast majority (89 %) were scored as having either Moderate, Severe, or Extreme Malocclusion.

Comparing infant oral glucose clearance with and without a water rinse

The purpose of this study was to test the hypothesis that a small rinse of water in an infant's mouth immediately following formula consumption would significantly improve oral glucose clearance. Though statistically significant results were not obtained at all time intervals, this study lends validity to the hypothesis that a small water rinse immediately following formula feeding could help enhance oral glucose clearance in infants.

Dental fracture fragment attachment: fracture model and luting agent comparisons

PURPOSE

The purpose of this study was twofold: 1. To compare two different research models for simulating a traumatic anterior tooth fracture: the blunt trauma method (standard method) and an AL2O3 sectioning method (experimental method). 2. To compare the bond strength of tooth fragments bonded with resin modified glass ionomer vs. a light cured composite resin.

METHODS

Two hundred bovine incisors were used in the study and kept in plain tap water throughout. The study consisted of five basic steps: 1. Fracture of the teeth by either blunt trauma (chisel and hammer) or AL2O3 sectioning disc. 2. Luting of the fractured fragments back to the teeth using either a composite resin or resin modified glass ionomer. 3. Thermocycling of the repaired teeth. 4. Dislodging the teeth to determine the strength of repair. 5. Determination of fracture type.

RESULTS

One-way ANOVA revealed a statistically significant difference in the forces required to fracture the resin modified glass ionomer and composite resin regardless of whether the teeth were originally fractured with the blunt force method (p=0.030) or the disc sectioning method (p=.001). One-way ANOVA also revealed a statistically significant difference between the forces required for fracture by blunt trauma and the disc fracture techniques with the resin modified glass ionomer group (p=0.000345). However, there was no significant difference when the two techniques were compared for the composite resin (p= 0.2941).

CONCLUSIONS

1. The resin modified glass ionomer was significantly stronger than the composite resin when both the blunt trauma and the disc fracture techniques were employed. 2. The study's results do not support substituting the ease of the AL2O3 disc for the more time-consuming blunt trauma method.

Low potential for climatic stress adaptation in a rainforest Drosophila species

The ability of sensitive rainforest species to evolve in response to climate change is largely unknown. We show that the Australian tropical rainforest fly Drosophila birchii exhibits clinal variation in desiccation resistance, but the most resistant population lacks the ability to evolve further resistance even after intense selection for over 30 generations. Parent-offspring comparisons indicate low heritable variation for this trait but high levels of genetic variation for morphology. D. birchii also exhibits abundant genetic variation at microsatellite loci. The low potential for resistance evolution highlights the importance of assessing evolutionary potential in targeted ecological traits and species from threatened habitats.

Cerebellar regulation of sensorimotor activity in brown trout

Evoked field potentials were recorded from the mesencephalic ('optic') tectum, cerebellar corpus, midline rhombencephalon, and spinal cord of decerebrated brown trout in response to single electrical shocks given to an optic nerve. Evoked responses were also recorded from the rhombencephalon and spinal cord following stimulation (singly and with trains) to the optic tectum and to the cerebellar corpus. The potentials recorded from the tectum in response to optic nerve stimulation were similar in form to those reported by other workers from other species of teleost. The rhombencephalic responses to optic nerve and tectal stimulation were complex and comprised presumed pre- and post-synaptic events. Cerebellar stimulation evoked no detectable responses in these brain regions, but when given prior to tectal stimulation (by up to 10 ms), tectally-evoked spinal cord responses were reduced in amplitude by as much as 85%. After cerebellar ablation, there was no difference from controls in the latency, form or amplitude of any response, even when tested with paired pulse stimulation. However, when the cerebellum was ablated, rhombencephalic and spinal responses to optic nerve and tectal stimulation were markedly enhanced (by 200-300%). These clear-cut complimentary consequences of cerebellar ablation or stimulation emphasize the gain-setting role of the cerebellum and indicate, at least in relation to optically evoked motor activity, that cerebellar regulation acts at the level of the supraspinal drive to spinal motor circuits and not within the sensory centers.

Fluoride varnish concentration gradient and its effect on enamel demineralization

PURPOSE

Two of the 4 fluoride varnishes available on the American market today are sold in 10-mL tubes of 5% NaF varnish (Duraphat and Duraflor). Pilot studies have shown that a separation of contents within these tubes exists. The purpose of the current study was 4-fold: (1) to measure the fluoride concentration gradient in 10-mL tubes of fluoride varnish, based on resting position of the tube prior to use; (2) to compare and contrast fluoride concentration gradients of Duraphat, Duraflor, and CavityShield; (3) to compare this gradient to the ability to inhibit caries in an artificial caries environment; and finally, (4) to determine if quantitative light fluorescence (QLF) can detect differences in lesions developed when exposed to an artificial caries environment and fluoride varnish.

METHODS

Human teeth specimens were subjected to a caries challenge and treated with a sample of fluoride varnish from 1 of 5 categories: Duraphat stored horizontally and vertically for 1 week, Duraflor stored horizontally and vertically for 1 week, or a CavityShield 0.4 mL "unidose." All specimens were then analyzed with the QLF system and with confocal microscopy.

RESULTS

Results showed no significant fluoride ppm differences exist between groups (P=.29). It was shown that the order in which Duraflor varnish was dispensed from tubes significantly affected the fluoride concentration (P<.05). The order effect was not significant for Duraphat (P=.99). QLF data analysis showed there was no significant difference (P>.05) in the amount of remineralization obtained by using any varnish stored in any position.

CONCLUSIONS

These results indicate that all 3 brands of fluoride varnish are able to remineralize incipient in vitro carious lesions, regardless of what part of the 10-mL tube the varnish is taken from. However, a fluoride concentration gradient exists in tubes of Duraflor. Also, QLF is able to detect demineralized and remineralized incipient lesions.

Comparison of electrosurgical and formocresol pulpotomy procedures in children

OBJECTIVES

Although previous studies have examined the electrosurgical pulpotomy technique for primary teeth, no well-controlled, clinical human trials have been published. The purpose of this study was to prospectively compare electrosurgical pulpotomies vs. formocresol pulpotomies in human vital primary molar teeth.

DESIGN

Fifty children were randomly divided into two groups, 25 receiving an electrosurgical pulpotomy and 25 receiving a formocresol pulpotomy.

RESULTS

After at least 5 months postoperative observation time, the clinical and radiographic success rates for the electrosurgical groups were 96 and 84%, respectively; and for the formocresol group, 100 and 92%, respectively.

CONCLUSION

There were no statistically significant differences between the success rates for the two groups at the P < 0.05 level as tested by Fisher's exact test. This study failed to demonstrate a difference in the success rate between the electrosurgical and formocresol pulpotomy techniques.

The impact of early palatal obturation on consonant development in babies with unrepaired cleft palate

OBJECTIVE

The purpose of this investigation was to determine whether palatal obturators enhance consonant development during babbling for babies with unrepaired cleft palate.

PARTICIPANTS

Fourteen babies with cleft palate who had worn anterior palatal obturators prior to palatal surgery were matched to 14 unobturated babies according to cleft type, sex, and age at time of presurgical evaluation.

MAIN OUTCOME MEASURES

Spontaneous vocalizations of the obturated and unobturated groups were compared to determine whether differences were evident in size of consonant inventory as well as place and manner of consonant production.

RESULTS

Paired t tests revealed no significant differences between the groups in size of consonant inventory or place and manner of consonant production. There was a trend for babies in the obturated group to produce more glottal consonants.

CONCLUSIONS

In general, the findings of this study suggested that palatal obturators do not appear to facilitate production of anterior palatal consonants during babbling.

Histological evaluation of electrosurgery and formocresol pulpotomy techniques in primary teeth in dogs

The purpose of this study was to compare pulpal and periapical tissue reactions to electrosurgery versus formocresol pulpotomy techniques in the primary teeth of dogs. The study was conducted on 33 primary teeth of three mongrel dogs between the ages of one to three months. Each dog had three teeth treated by Formocresol Pulpotomy with Mechanical Coronal Pulp Removal (FC), three teeth treated by Electrosurgery Pulpotomy with Mechanical Coronal Pulp Removal (ES/MCPR), three teeth treated by Electrosurgery Pulpotomy with Electrosurgical Coronal Pulp Removal (ES/ECPR), and two teeth serving as untreated Controls. Dogs one, two and three were sacrificed performing the pulpotomies at two, four and six weeks, respectively. The pulp, periapical tissue and after surrounding bone were submitted to histological examination and the histological reaction was recorded. The results were fourteen out of 18 unfavorable and zero out of three favorable histological reactions occurred in the FC treated teeth. Six out of 18 unfavorable and one out of three favorable histological reactions occurred in the ES/MCPR treated teeth. Nine out of 18 unfavorable and two out of three favorable histological reactions occurred in the ES/ECPR treated teeth. One out of 18 unfavorable and zero out of three favorable histological reactions occurred in the untreated Control teeth. The conclusion of this study is that of the three experimental groups, the teeth treated by Electrosurgery Pulpotomy with either Mechanical or Electrosurgical Coronal Pulp Removal exhibited less histopathological reaction than the teeth treated by Formocresol Pulpotomy.

The resuscitation status of a patient: a constant dilemma

Since the first description of closed chest cardiac massage in 1960, healthcare has evolved considerably. The modern-day skill and expertise of both doctors and nurses in cardiopulmonary resuscitation (CPR) techniques are now supported by an advanced medical technology. Indeed, CPR is now perceived as the definitive life-saving procedure. However, paradoxically, it has also prolonged the process of dying and denied many patients a dignified and peaceful death. It has also denied the patient's loved ones the opportunity to be present at the time of death. The main focus of this article is to explore the current ethical issues in clinical practice relating to determining the resuscitation status of patients. Attention will also be given to patient advocacy, and the nurse's role in supporting this concept.

von Willebrand disease in a pediatric-based population--comparison of type 1 diagnostic criteria and use of the PFA-100 and a von Willebrand factor/collagen-binding assay

Definitive diagnosis of type 1 von Willebrand Disease (VWD) remains a problem. Provisional consensus guidelines for the diagnosis of definite and possible type 1 VWD were prepared by the Scientific Subcommittee on von Willebrand factor (VWF) of the Scientific and Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis (ISTH) during the 1996 annual meeting for the specific purpose of further evaluation in retrospective and prospective studies by a Working Party on Diagnostic Criteria (1996 Annual Report of the SSC/ISTH Subcommittee on VWF). In the first phase of this study, we compared 2 definitions of type 1 VWD. each with 3 criteria: significant bleeding history, laboratory investigations, and family history. Using the ISTH consensus guidelines for type 1 VWD definition, significantly fewer patients were diagnosed with definite type 1 disease as compared to our "in house" Hospital for Sick Children (HSC) criteria (4 vs. 31). While we recognize that the provisional ISTH consensus guidelines were not intended for clinical use, we believe that the results of our studies are of interest and will assist in any future refinements to the ISTH guidelines. In the second phase of this study, we investigated the utility of 2 new tests, a laboratory screening test and a functional test, for VWD in our well characterized, pediatric-based population. The Platelet Function Analyzer (PFA-100) provides an in vitro measure of primary hemostasis under conditions of high shear, using disposable cartridges containing collagen and either epinephrine or ADP. All tested subjects with types 2 or 3 VWD had prolonged PFA-100 closure times (CTs) with both cartridge types (n = 17) and prolonged bleeding times (n = 14). In subjects with definite type 1 VWD, 20/24 (83%) had prolonged CTs with the collagen/ADP cartridge (19/24 (79%) with collagen/epinephrine), compared with 7/26 (27%) with prolonged bleeding times. In subjects with definite types 1, 2, or 3 VWD, collagen/ADP CTs were abnormal in 37/41 subjects, giving an overall sensitivity of 90%. With this high sensitivity, the PFA-100 is a better screening test for VWD than the bleeding time. We also tested a VWF collagen-binding assay (VWF:CBA) as a functional test for VWF, in comparison with the more routinely-used ristocetin cofactor assay (VWF:RC0). The VWF:CBA is based on an ELISA technique, which has the potential to be more reproducible than the VWF:RC0. We found that the VWF:CBA detected 43/49 (88%) subjects with definite types 1, 2, or 3 VWD, performing as well as the VWF:RC0, that detected 42/48 (88%). We also showed that, used in conjunction with VWF antigen levels, the VWF:CBA may be useful in classification of VWD subtypes.

Progression of interproximal caries in the primary dentition

While studies have addressed the diagnosis and progression of interproximal carious lesions within a primary tooth, few studies have addressed the development of proximal lesions in adjacent primary molars. The purpose of this study was to examine retrospectively the long term interproximal caries progression in primary molar teeth. Dental records of 150 children were retrospectively reviewed, 76 from a university pediatric dentistry clinic and 74 from a pediatric dentistry private practice. Out of the 387 teeth initially diagnosed with proximal caries, the combined university and private practice results for timing of the development of proximal lesions on adjacent tooth surfaces showed the following: simultaneous development-162 (41.9%); 1 to 24 months-65 (16.8%); 24 to 60 months-40 (10.3%); never-120 (31.0%). The combined results for formation of proximal caries in posterior quadrants showed that out of the 150 patients, the timing for development of additional quadrants with proximal caries was as follow: simultaneous development: 77 (51.3%); 1 to 24 months 31, (20.7%); 24 to 60 months 25, (16.7%); never 17 (11.3%). The conclusions of the study are that 69% of the primary molar teeth with proximal caries developed caries on the adjacent proximal surface and 89% of the patients who developed a proximal carious lesion on a primary molar tooth within one quadrant developed another primary molar proximal lesion in another quadrant.

Platelet function in autoimmune (idiopathic) thrombocytopenic purpura

Platelets play an essential role in the formation of haemostatic plugs. The quantitative defect of platelets in autoimmune (idiopathic) thrombocytopenic purpura (ITP) can result in bleeding complications, but most ITP patients have platelets with normal or enhanced function. Platelets in ITP are large, young, so-called "stress" platelets with increased platelet-associated autoimmune antibody (immunoglobulin G). Young stress platelets are more functional platelets, and their presence may account for bleeding times in ITP patients that are shorter than would be predicted on the basis of the patients' (low) platelet counts. Some ITP patients have significant mucocutaneous bleeding with platelet counts >50 x 10(9) l(-1); this may be due to qualitative platelet dysfunction (e.g. brought about by inhibitory antiplatelet autoantibodies).

The Platelet Function Analyzer (PFA-100): a novel in-vitro system for evaluation of primary haemostasis in children

The PFA-100 system provides an in-vitro method of assessing primary platelet-related haemostasis by measuring the time (the closure time, or CT) taken for a platelet plug to occlude a microscopic aperture cut into a membrane coated with collagen and either epinephrine or ADP. We used the system to establish normal ranges for CTs in healthy children, adults and neonates. Mean CTs of healthy children were independent of the needle gauge used (21G or 23CG) for blood sampling; they were very similar to the mean CTs of healthy adults, but longer than mean CTs of healthy neonates. Although children with haemophilia had normal CTs, the PFA-100 system was found to be potentially useful in screening for von Willebrand disease in children.

A comparison of a hybrid light-cured glass-ionomer base and liner vs. a light-cured resin tooth fragment attachment

PURPOSE

The purpose of this study was to compare the dislodgement strengths and fracture types for reattached tooth fragments using a light-cured composite resin material, a hybrid light-cured glass ionomer base, and a hybrid light-cured glass ionomer liner.

METHODS

Seventy-five bovine incisor teeth were fractured, randomly divided into three groups of equal number, and then luted back together with three different materials (Universal Bonding Agent/TPH Composite Resin; VariGlass VLC Base; and VariGlass VLC Liner: LD Caulk Div Dentsply Int Inc, Milford, DE). The reattached fragments were subjected to thermocycling with a 40 degrees C differential and then were loaded until the force required to dislodge the fragment was reached.

RESULTS

The mean dislodgement strengths were 36.8 (+/- 25.6) kg for the composite resin, 36.4 (+/- 26.7) kg for the glass ionomer base, and 31.4 (+/- 29.5) kg for the glass ionomer liner. Cohesive fractures occurred in 73% of the dislodgements.

CONCLUSIONS

There was no statistically significant difference demonstrated (P < 0.05) between the three groups in terms of both dislodgement strength and fracture type.

Dentin dysplasia, type II linkage to chromosome 4q

Dentin dysplasia, type II (MIM*125420) is an autosomal dominant disorder of dentin development. Clinically the primary dentition appears opalescent, and radiographically the pulp chambers are obliterated, resembling dentinogenesis imperfecta. However, unlike dentinogenesis imperfecta, the permanent teeth in dentin dysplasia, type II are normal in color and, on radiographs, have a thistle-tube pulp chamber configuration with pulp stones. The similarity of the primary dentition phenotype suggested that the gene for dentin dysplasia, type II is allelic with the gene for dentinogenesis imperfecta, Shields type II (DGII; MIM*125490), which has been localized to chromosome 4q13-q21. Twenty-four members of a three generation family in which ten members are affected with dentin dysplasia, type II were genotyped for microsatellite alleles specific for the area of chromosome 4q linked to DGII. Linkage was assessed by using the LINKAGE computer program, assuming autosomal dominant inheritance, a disease allele frequency of 0.0001, and complete penetrance. The maximum two-point LOD score (Zmax = 4.2 at theta = 0.0) was obtained with SPPI and D4S2691. Multipoint analysis gave a maximum LOD score of 4.33. The candidate region for dentin dysplasia, type II is approximately 14.1 cM, includes SPPI, D4S2691, D4S2690, D4S451, and D4S2456, and overlaps the most likely location of the DGII locus. A candidate gene for DGII should also be considered a candidate gene for dentin dysplasia, type II.

One-stage reconstruction for defects caused by cancrum oris (noma)

Cancrum oris is a disease process that has been described for centuries, but now presents primarily in developing countries. The disease in known to occur in association with poor nutrition and exanthematous infections. The acute disease occurs usually in young children, and the infectious process causes destruction of the involved orofacial tissues with variable degrees of tissue loss and scar reaction in those who are affected and survive. The chronic sequelae of the acute disease process often require reconstructive surgery. We present the natural history of the disease process and its causes, and demonstrate the wide spectrum of resulting defects that challenge the reconstructive surgeon. Because of the socioeconomic situation inherent with these patients and the volume of patients in need of treatment with this disease, innovative and efficient treatment is required. We have demonstrated methods of reconstructive surgery that differ from the multiple staged procedures described in previous studies by allowing for one-stage surgical reconstruction of even the most complex cases. This allows for treatment of the majority of patients in their native countries in a cost-effective and safe manner, and treatment of more severely afflicted individuals in modern medical centers without their having to spend a long time period away from their homes.

Using a resin-modified glass ionomer as an occlusal sealant: a one-year clinical study

The authors compared the retention and clinical performance of a resin-modified glass ionomer, or RMGI, restorative and a light-cured resin sealant. The first permanent molars on one side of the dental arch in 50 children were sealed with an RMGI, and the same teeth on the other side were sealed with a resin sealant. At baseline, six months after placement and one year after placement, examiners documented sealant retention, secondary caries, marginal discrepancy and marginal staining. In general, the RMGI appeared to wear markedly. At one year, the retention of the RMGI was significantly less than the resin, but the RMGI had significantly fewer marginal discrepancies. There were no significant differences in caries development or marginal discoloration.

Electrosurgical pulpotomy: a retrospective human study

While the formocresol pulpotomy has enjoyed long-term clinical use and success, concerns over its toxicity and mutagenicity have prompted research into other pulpotomy techniques. The purpose of this study was to observe retrospectively the results of the electrosurgical pulpotomy technique used on primary molar teeth requiring pulp therapy, secondary to carious involvement. The mean age at the time of treatment was 5 years, 11 months and the mean postoperative observation time was 2 years, 3 months. Of the 164 teeth studied, 127 were normal at the last observation visit; 32 had undergone exfoliation; 4 had an abnormality associated with the pulpotomized tooth, but were not considered failures; and 1 was considered a failure. This is a 99.4 percent success rate. Compared to a formocresol pulpotomy study of similar design, the success rate for the electrosurgical pulpotomy procedure in this study is higher at the statistically significant level of p < 0.01.

The brow slide: a technique for the aesthetic treatment of eyebrow tumors

Skin neoplasms involving the eyebrow are not an uncommon problem. Standard surgical resections that depend on elliptical excision and closure tend to either remove an excessive amount of brow or place scars in an unfavorable position. We present a simple technique that allows for maximal brow preservation, alignment of remaining brow, and a minimal amount of exposed scars.

Epi Info: a general-purpose microcomputer program for public health information systems

Epi Info is a general-purpose set of computer programs for word processing, database management, statistics, and graphics developed over the past five years at the Centers for Disease Control and the World Health Organization. The programs allow rapid questionnaire construction, data entry, and analysis during epidemic investigation. Both data entry and analysis can be programmed to provide customization and automatic operation for more permanent systems, such as those for disease or injury surveillance. Epi Info is in the public domain and copies may be freely distributed. It requires an IBM-compatible micro-computer with at least 512 kilobytes of memory. Translations into French and Spanish are in progress; a translation kit is available to facilitate translation into other languages.

Diphallia and hindgut duplication

Diphallia is a rare congenital condition that presents in many, varied ways. Associated anomalies are to be expected. These anomalies should be sought out and treated as early in the patient's life as possible because they are the principal cause of mortality in these individuals. Half the patients reviewed by Ravitch in 1953 with duplication of the colon and genital tracts died of intestinal complications. Definitive genital repair should be done at an age where the anatomy is of large enough caliber for eased surgical manipulation, but prior to the age of recall. From our experience with hypospadias repair, the optimal age seems to be 12 months of age. Each case must be treated individually in order to achieve the best functional and aesthetic result.

Indiana infant-toddler dental care survey

The purpose of this project was to survey Indiana dentists concerning dental care for Indiana infants and toddlers. Dental care issues covered were the age for a child's first dental visit, frequency of rampant or nursing caries cases examined, and dental referral sources for infants and toddlers. The survey also helped determine the dentist's perception of parents' attitudes toward services recommended by the dentist. A twelve question survey was mailed to 2006 general and pediatric dentists in the State of Indiana. The results of the survey were: 1. A large percentage of Indiana dental practitioners do not recommend the first dental visit or examine children for their dental visit until the child is more than one year of age. 2. A majority of Indiana dental practitioners see children with nursing caries or rampant caries on a monthly basis. 3. The majority of Indiana dental practitioners refer children with nursing caries to pediatric dentists for treatment. 4. Although the full treatment plan may undergo some modification based on various parental concerns, a majority of practitioners do not experience difficulty in obtaining treatment plan acceptance for nursing or rampant caries cases.

Reconstruction of traumatically acquired defects of the phallus

Trauma to the male phallus may be treated in a systematic approach to achieve aesthetically and functionally pleasing results. Isolated burns should be treated early with excision and preputial flap or skin graft closure. Avulsion injuries are closed primarily or skin grafted. Subtotal loss can be treated with penile lengthening techniques. Total loss is treated with reimplantation or microvascular free tissue transfer phalloplasty. There are reconstructive surgical options, instead of penectomy, in patients with penile malignancies.

Pharmacological control of the pattern of activity in leech Retzius neurones

1. Changes in the activity pattern of leech Retzius (R) cells were investigated using intracellular recording. 2. The presence of an after-hyperpolarisation (AHP) is closely related to activity pattern; regular firing being associated with an AHP, bursting with its absence. 3. Increasing external calcium (Cao), cyclic AMP levels or activity of kinase A enhanced the AHP. 4. Bursting was induced by low Cao, EGTA, barium, cobalt or injection of phorbol ester. 5. Reduction of Cao to zero caused long paroxysmal depolarising shifts of potential which could be reversed to bursting by cobalt, IBMX or injection of kinase A catalytic subunit. 6. The possible roles of a calcium-activated potassium channel and protein phosphorylation in regulating the activity of the cell are discussed.

Dental management of oculodentodigital dysplasia: report of case

Oculodentodigital dysplasia is a rare autosomal dominant syndrome characterized by typical facies and certain anomalies of the eyes, dentition and digits. This report describes the case of a 2.5-year-old white male with oculodentodigital dysplasia and his comprehensive dental treatment. Aggressive treatment to maintain the integrity of the patient's primary dentition was provided. The characteristic physical and genetic findings of oculodentodigital dysplasia were also described.

A new approach to the analysis of complex dose-response relationships: a multivariate study of octopamine action on the leech Leydig neurone

Octopamine (OA) hyperpolarizes leech Leydig neurones but response amplitudes and thresholds vary. Associations between response, OA dose and other variables [initial resting potential, action potential (AP) frequency and amplitude, temperature, microelectrode resistance, position of ganglion along nerve cord, animal, treatment order] were examined using canonical correlation. A complex response was expressed by summing changes in membrane potential and AP frequency over 2 min of OA treatment. Only dose and ganglion position influenced this response. One significant canonical variate related dose to immediate changes in membrane potential and summed changes in AP frequency throughout the OA effect. Response to OA was greater in cells in posterior ganglia.

Medical and nutritional aspects of intractable diarrhea

Diarrhea can be due to at least five pathogenetic mechanisms. Major examples of each are presented to better illustrate each type of diarrhea and to provide a springboard for discussion of the nutritional management of each class of diarrhea. Certainly, specific diseases require specific therapies, such as avoidance of gluten in adult coeliac disease, but the major dietary/nutritional alterations and subsequent treatment are similar for each class of disease. Nowhere in medicine and nutrition is an admonition to the health care team more important and more proper than in the treatment of chronic diarrheas: The feeding of healthy man, as well as the diet of the sick cannot be left to chance, guided by the appetite, or ruled by tradition, but can be safely directed only according to the laws of digestion and metabolism.

Determination of phosphorus and sulfur in fuel rich air-hydrogen flames

Excitation conditions for the green HPO bands, the uv PO bands, and the violet S(2) bands were explored. A cylindrical glass shield placed around the tip of a Beckman (sprayer) burner provided a simple arrangement to isolate a fuel rich environment of a reversed air-hydrogen flame. Samples were converted to aerosol in a separate nebulization chamber. The HPO band at 5262 A gave a detection limit of 6 microg/ml; the S(2) band, 5 microg/ml. Owing to low flame noise, both detection limits could be improved with interference filters in place of the Beckman small quartz monochromator. The PO bands are emitted best from fuel rich oxygen-acetylene flames with the normal Beckman sprayer burner. The significant aspect of this study lies in the introduction of liquid samples and circumvention of lengthy, and often uncertain, decomposition steps when handling many types of organic and biochemical compounds containing phosphorus and sulfur.