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PURPOSE/OBJECTIVES: Multimedia presentations and online platforms are used in dental education. Though studies indicate the benefits of video-based lectures (VBLs), data regarding user reception and optimal video features in dental education are limited, particularly on Web 2.0 platforms like YouTube. Given increasing technology integration and remote learning, dental educators need evidence to guide implementation of YouTube videos as a freely available resource. The purpose of this study is to determine video metrics, viewership and format efficacy for dental education videos. METHODS: First, a cross-sectional survey was conducted of viewers (N = 683) of the Mental Dental educational videos on YouTube. Analytics were evaluated for 677 200 viewers to assess audience demographics, retention and optimal video length. Second, a randomized crossover study was conducted of dental students (N = 101) who watched VBLs in either slideshow or pencast formats and were tested on content learning to compare format efficacy. RESULTS: Most viewers of Mental Dental videos were dental students (44.2%) and professionals (37.8%) who would likely recommend the platform to a friend or colleague (Net Promoter Score = 82.1). Audience retention declined steadily at 1.34% per minute, independent of video length. Quiz performance did not differ between slideshow and pencast videos, with students having a slight preference for slideshows (P = 0.049). CONCLUSIONS: Dental students and professionals use VBLs and are likely to recommend them to friends and colleagues. There is no optimal video length to maximize audience retention and lecture format (slideshow vs. pencast) does not significantly impact content learning. Results can guide implementation of VBLs in dental curricula.
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Medios de Comunicación Sociales , Humanos , Grabación en Video , Estudios Cruzados , Estudios Transversales , Educación en OdontologíaRESUMEN
BACKGROUND: In recent years, the Web has become a source of medical information for patients, even though the information available online may be incorrect or qualitatively inadequate. Younger generations, immersed in a digital environment since a very tender age, are more likely to get informed online. This study aims to understand the relevance of online information for prospective orthodontic patients and to investigate the effects of digital research on patients' decision-making process, and it also aims to investigate potential generational differences between digital natives and digital immigrants. MATERIALS AND METHODS: An anonymous questionnaire was developed to investigate patients' orthodontic-themed Web searches as well as the effects digital material had on their decision-making process. Before submitting the newly designed survey to patients, it was validated in a pilot study. Univariate analysis was applied to analyze the relationship between the demographic characteristics of respondents and their answers on the use of digital research for the decision-making process. RESULTS: 64.6% of the study population searched the Web for orthodontic information prior to their visit. Google was the most used platform regardless of patients' age. The perceived reliability of online sources varied significantly with age. Men displayed more trusting behavior towards their doctor than women. Prospective patients' satisfaction with affected patients' decision-making processes, and the perceived reliability of online sources of information had repercussions on the doctor-patient relationship. CONCLUSIONS: Orthodontists should be aware that the majority of patients use the Internet as a source for orthodontic information, and that patients who are digital immigrants are more prone to trust the information found online. Patients who perceive the information found on the Web as either useful or reliable don't easily discard it, even if it is inconsistent with the orthodontist's opinion.
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Internet , Relaciones Médico-Paciente , Masculino , Humanos , Femenino , Estudios Transversales , Estudios Prospectivos , Proyectos Piloto , Reproducibilidad de los Resultados , Encuestas y CuestionariosRESUMEN
INTRODUCTION: The conundrum of determining how to treat a patient with Class III malocclusion is significant, creating a burden on the patient and challenging the orthodontist. The objective of this study was to employ a statistical prediction model derived from our previous cephalometric data on 5 predominant subtypes of skeletal Class III malocclusion to test the hypothesis that Class III subtypes are associated with treatment modalities (eg, surgical vs nonsurgical) and treatment outcome. METHODS: Pretreatment lateral cephalometric records of 148 patients were digitized for 67 cephalometric variables, and measurements were applied to a mathematical equation to assign a Class III subtype. Subjects were assigned to either a surgical or nonsurgical group depending on the treatment received. Treatment outcome was determined by facial profile and clinical photographs. Log binomial models were used for statistical analysis. RESULTS: Subtype 1 (mandibular prognathic) patients were 3.5 × more likely to undergo orthognathic surgery than subtypes 2/3 (maxillary deficient) and 5.3 × more likely than 4/5 (combination). Subtype 1 patients were also 1.5 × more likely to experience treatment failure than subtypes 2/3 (maxillary deficient) and 4/5 (combination). CONCLUSIONS: This assessment of a systematic method to characterize patients with Class III malocclusion into subtypes revealed that subtype 1 (mandibular prognathic) showed a likelihood to undergo orthognathic surgery while subtypes 2/3 experienced significantly lower treatment failure (in response to orthodontics alone). Further refinement of the equation may yield a reliable prediction model for earlier identification of surgical patients and also provide predictive power of Class III treatment outcomes.
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Maloclusión de Angle Clase III , Procedimientos Quirúrgicos Ortognáticos , Cefalometría , Humanos , Aprendizaje Automático , Mandíbula , Maxilar , PronósticoRESUMEN
INTRODUCTION: Referrals from general dentists are a significant source of orthodontic patients, but our knowledge of factors guiding referral decisions predates recent marketplace trends of direct-to-consumer products and broad digitization. To provide orthodontists with current, nationwide data on referral values and communication preferences, a mixed-methods study was conducted. METHODS: Semistructured interviews were conducted with practicing general dentists (n = 23), and interviews were analyzed to identify factors important to communication and referrals. Qualitative data provided the foundation to develop and pretest a survey distributed nationally to American Dental Association general dentists through email (n = 373). Survey results were evaluated using bivariate and descriptive statistics. RESULTS: Although 42% of general dentists provide orthodontics, of those, 68% report insufficient orthodontic training in dental school, and 61% have increased orthodontic care in recent years. General dentists refer to orthodontists for complex cases and growing patients, with the orthodontist's perceived skill and proximity to the patient being important for choosing a specific orthodontic practice. Phone (70%) and email (61%) are the most used interoffice communication methods, with email (40%) and then phone (30%) being the most preferred. The most important aspects of a working relationship were patient satisfaction and final occlusal outcome, whereas the best way to boost referrals was through improving communication. CONCLUSIONS: Excellent care and patient satisfaction remain primary motivators for referrals from generalists to orthodontists. An improved orthodontic curriculum is needed for general dentists. Good communication with dentists is critical for growing referral streams and enhancing patient care.
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Ortodoncia , Ortodoncistas , Atención Odontológica , Odontólogos , Humanos , Derivación y Consulta , Encuestas y CuestionariosRESUMEN
INTRODUCTION: Orthodontic residents face challenges unparalleled to their predecessors, including competitive marketplaces, rising debt burdens, and changing demographics that have contributed to the shift in initial career choice from owner to employee. We aim to understand factors important to orthodontists at different career stages and the impact on job satisfaction through a sequential mixed methodology study. METHODS: Semistructured interviews were conducted with 25 orthodontic residents and practitioners. A survey was developed from qualitative findings that explored career decision-making of orthodontic residents and practicing orthodontists, with descriptive and bivariate statistical analyses (n = 343 orthodontists and 185 residents). RESULTS: Graduating orthodontic residents are choosing employment over ownership as their initial job, prioritizing high income to offset the educational debt. The majority of residents report thinking about their debt very often to all of the time and find it very to extremely stressful. Current residents have long-term goals of ownership, whereas practicing doctors of both genders became owners at equal frequencies. However, on average, women earn $119,000 less per year and report being the primary family caretaker more often than men. CONCLUSIONS: Excellent patient care, work-life balance, and sufficient income are the most important drivers for career choices and job satisfaction for orthodontists of all ages. Despite debt, most residents and working orthodontists report a high level of job satisfaction and would recommend the field of orthodontics to others.
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Internado y Residencia , Ortodoncia , Selección de Profesión , Femenino , Humanos , Satisfacción en el Trabajo , Masculino , Ortodoncistas , Factores Sexuales , Encuestas y CuestionariosRESUMEN
OBJECTIVE: A third focused workshop explored how to transfer novel findings into clinical orthodontic practice. SETTING AND SAMPLE POPULATION: Participants met at the Scottsdale Plaza Resort, 12-16 September 2018 for the Consortium for Orthodontic Advances in Science and Technology 2018 Innovators' Workshop. Thirty speakers and four lunch-hour focus group leaders shared and exchanged information with approximately 45 registered attendees. MATERIAL AND METHODS: This Innovators' Workshop was organized according to five themed sessions which covered: (a) The relevance of genetics, biology and environment to therapeutic outcomes; (b) Application of bioinformatics in craniofacial research; (c) Regeneration with and for orthodontic treatment; (d) Technology in precision orthodontics; and (e) Muscle, joint, and airway: Growth, function and pain. RESULTS: The papers that comprise this supplemental issue exemplify the important outcomes of the 2018 COAST Workshop. In addition, matters identified as important needs include improved understanding of neural, skeletal and muscle tissue crosstalk in early craniofacial growth; standardized methods for three-dimensional radiographic and surface landmark and reference plane identification, measurements and serial superimpositioning techniques for use in the clinic; sharing and making available existing data sets (eg, cone beam computed tomography images, genotype-phenotype data); evidence of the usefulness and effectiveness of new devices; guidelines of what to measure to characterize the airway; more information about the influences of the soft tissues on craniofacial morphology; and information about effective digital work flows applied to clinical and educational settings. CONCLUSIONS: Progress in bridging the biology-technology gap has identified new needs for improvements in orthodontics and craniofacial care.
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Ortodoncia , Tomografía Computarizada de Haz Cónico , Imagenología TridimensionalRESUMEN
OBJECTIVE: The morbidity and mortality associated with the Marfan Syndrome (MFS) warrant timely diagnosis and intervention that can improve long-term prognosis. The aim of this study was to test the hypothesis that a distinct craniofacial morphology exists for patients with MFS that can be described quantitatively and qualitatively. METHODS: Subjects with a positive diagnosis of MFS were recruited for this study (N = 36). Craniofacial anthropometric measurements were made on each subject and compared to established norms of age- and sex-matched controls using z-scores calculated for measurements of MFS patients. Lateral and frontal photographs were obtained to make qualitative assessments and describe facial features of subjects, and a clinical examination was completed to document occlusal relationships. RESULTS: The subjects were primarily female (58%) ranging in age between 4 and 57 years (mean age 10.7 ± 6.0 years). Comparison of craniofacial measurements revealed that for 10 of the 12 measurements, ≥65% of the study population had a z-score of ± 2 and fell within the normal range for facial dimension. For 2 of the 12 measurements, over half of the subjects fell outside of the normal range (z-score < -2 or > 2) for facial dimension. Specifically, the majority of participants resided in the supernormal category for biocular width and the subnormal category for width of the face. Photographic assessment revealed retrognathia (54%) and down-slanting palpebral fissures (62%) were most prevalent in MFS patients. CONCLUSION: Our data suggest there are quantitative differences in the facial morphology of patients with MFS when compared to a control population.
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Síndrome de Marfan , Retrognatismo , Adolescente , Adulto , Niño , Preescolar , Cara , Femenino , Humanos , Persona de Mediana Edad , Pronóstico , Adulto JovenRESUMEN
BACKGROUND: Aim of this work was to describe a rare inheritance pattern of Primary Failure of Eruption (PFE) in a small family with incomplete penetrance of PFE and a novel nonsense PTH1R variant. CASE PRESENTATION: The proband, a 26 year-old man with a significant bilateral open-bite, was diagnosed with PFE using clinical and radiographic characteristics. DNA was extracted from the proband and his immediate family using buccal swabs and the entire PTH1R coding sequence was analyzed, revealing a novel heterozygous nonsense variant in exon 7 of PTH1R (c.505G > T). This variant introduces a premature stop codon in position 169, predicted to result in the production of a truncated and non-functional protein. This variant has never been reported in association with PFE and is not present in the Genome Aggregation Database (gnomAD). Interestingly, the c.505G > T variant has also been identified in the unaffected mother of our proband, suggesting incomplete penetrance of PFE. CONCLUSIONS: In this study, we report a new PTH1R variant that segregates in an autosomal dominant pattern and causes PFE with incomplete penetrance. This underlines the diagnostic value of a thorough clinical and genetic analysis of all family members in order to estimate accurate recurrence risks, identify subtle clinical manifestations and provide proper management of PFE patients.
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Mutación/genética , Receptor de Hormona Paratiroídea Tipo 1/genética , Enfermedades Dentales/genética , Adulto , Codón sin Sentido/genética , Exones/genética , Humanos , Masculino , Penetrancia , Análisis de Secuencia de ADNRESUMEN
PURPOSE OF REVIEW: The ebb and flow of genetic influence relative to the understanding of craniofacial and dental disorders has evolved into a tacit acceptance of the current genetic paradigm. This review explores the science behind craniofacial and dental disorders through the lens of recent past and current findings and using tooth agenesis as a model of advances in craniofacial genetics. RECENT FINDINGS: Contemporary studies of craniofacial biology takes advantage of the technological resources stemming from the genomic and post-genomic eras. Emerging data highlights the role of key genes and the epigenetic landscape controlling these genes, in causing dentofacial abnormalities. We also report here a novel Glu78FS MSX1 mutation in one family segregating an autosomal dominant form of severe tooth agenesis as an illustration of an evolving theme, i.e., different mutations in the same gene can result in a spectrum of dentofacial phenotypic severity. The future of clinical therapeutics will benefit from advances in genetics and molecular biology that refine the genotype-phenotype correlation. Indeed, the past century suggests a continued convergence of genetic science in the practice of clinical dentistry.
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Anodoncia/genética , Regulación del Desarrollo de la Expresión Génica/genética , Diente Supernumerario/genética , Epigénesis Genética , Mutación del Sistema de Lectura , Humanos , Factores Reguladores del Interferón/genética , Factor de Transcripción MSX1/genética , Mutación , FenotipoRESUMEN
TET/JBP enzymes oxidize 5-methylpyrimidines in DNA. In mammals, the oxidized methylcytosines (oxi-mCs) function as epigenetic marks and likely intermediates in DNA demethylation. Here we present a method based on diglucosylation of 5-hydroxymethylcytosine (5hmC) to simultaneously map 5hmC, 5-formylcytosine, and 5-carboxylcytosine at near-base-pair resolution. We have used the method to map the distribution of oxi-mC across the genome of Coprinopsis cinerea, a basidiomycete that encodes 47 TET/JBP paralogs in a previously unidentified class of DNA transposons. Like 5-methylcytosine residues from which they are derived, oxi-mC modifications are enriched at centromeres, TET/JBP transposons, and multicopy paralogous genes that are not expressed, but rarely mark genes whose expression changes between two developmental stages. Our study provides evidence for the emergence of an epigenetic regulatory system through recruitment of selfish elements in a eukaryotic lineage, and describes a method to map all three different species of oxi-mCs simultaneously.
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5-Metilcitosina/metabolismo , Basidiomycota/metabolismo , Dioxigenasas/metabolismo , Proteínas Fúngicas/metabolismo , Basidiomycota/genética , Basidiomycota/crecimiento & desarrollo , Cromosomas Fúngicos/genética , Metilación de ADN , Elementos Transponibles de ADN/genética , Dioxigenasas/genética , Proteínas Fúngicas/genética , Regulación del Desarrollo de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Genoma Fúngico/genética , Células HEK293 , Humanos , Hifa/genética , Hifa/crecimiento & desarrollo , Hifa/metabolismo , Oxidación-Reducción , Análisis de Secuencia/métodos , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/metabolismoAsunto(s)
Ortodoncia , Ortodoncistas , Humanos , Encuestas y Cuestionarios , Técnicas de Movimiento Dental , Estados UnidosRESUMEN
INTRODUCTION: Proper diagnosis and management of eruption disturbances remains challenging but is critical to a functional occlusion. The objective of this study was to establish definitive criteria to differentiate and diagnose eruption disorders, specifically primary failure of eruption (PFE) and ankylosis. METHODS: Sixty-four affected persons were placed into 3 cohorts: PFE diagnosed through confirmed PTH1R mutation (n = 11), PFE diagnosed based on clinical criteria (n = 47), and ankylosis diagnosed based on clinical criteria (n = 6). These groups were assessed to identify clinical features that differentiate PFE and ankylosis. RESULTS: Ninety-three percent of the subjects in the genetic and clinical PFE cohorts combined (n = 58) and 100% in the genetic PFE cohort had at least 1 infraoccluded first permanent molar. Additionally, a novel functional PTH1R mutation, 1092delG, was identified and linked to PFE in the deciduous dentition. CONCLUSIONS: An infraoccluded, supracrestal first molar is a hallmark of PFE, often involving both arches in the permanent or deciduous dentition, and with unilateral or bilateral affection, infraoccluded second premolar or second molar, and multiple affected adjacent teeth. Our results further suggest that PFE and ankylosis might be clinically indistinguishable without knowledge of prior trauma, treatment history, genetic information, or obliteration of the periodontal ligament space.
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Erupción Dental/fisiología , Adolescente , Diente Premolar/patología , Cefalometría/métodos , Niño , Estudios de Cohortes , Exones/genética , Estudios de Asociación Genética , Genotipo , Guanina , Humanos , Maloclusión de Angle Clase III/fisiopatología , Diente Molar/patología , Fenotipo , Fotografía Dental , Polimorfismo de Nucleótido Simple/genética , Radiografía de Mordida Lateral , Radiografía Panorámica , Receptor de Hormona Paratiroídea Tipo 1/genética , Eliminación de Secuencia/genética , Anquilosis del Diente/diagnóstico , Anquilosis del Diente/genética , Enfermedades Dentales/diagnóstico , Enfermedades Dentales/genética , Erupción Ectópica de Dientes/diagnóstico , Erupción Ectópica de Dientes/genética , Raíz del Diente/anomalías , Diente Primario/fisiopatología , Diente Impactado/diagnóstico , Diente Impactado/genética , Diente no Erupcionado/diagnóstico , Diente no Erupcionado/genéticaRESUMEN
BACKGROUND: Primary failure of eruption (PFE) is a hereditary condition, and linkage with variants in the PTH1R gene has been demonstrated in many cases. The clinical severity and expression of PFE is variable, and the genotype-phenotype correlation remains elusive. Further, the similarity between some eruption disorders that are not associated with PTH1R alterations is striking. To better understand the genotype-phenotype correlation, we examined the relationship between the eruption phenotype and PTH1R genotype in 44 patients with suspected PFE and 27 unaffected relatives. Sanger sequencing was employed to analyze carefully selected PFE patients. Potential pathogenicity of variants was evaluated against multiple genetic databases for function prediction and frequency information. RESULTS: Mutational analysis of the PTH1R coding sequence revealed 14 different variants in 38 individuals (30 patients and 8 first-degree relatives), 9 exonic and 5 intronic. Their pathogenicity has been reported and compared with the number and severity of clinical signs. In 72.7% of patients with pathogenic variants, five clinical and radiographic criteria have been found: involvement of posterior teeth, involvement of the distal teeth to the most mesial affected, supracrestal presentation, altered vertical growth of the alveolar process and posterior open-bite. In cases with mixed dentition (3), the deciduous molars of the affected quadrant were infraoccluded. DISCUSSION: The probability of an affected patient having a PTH1R variant is greater when five specific clinical characteristics are present. The likelihood of an eruption defect in the absence of specific clinical characteristics is rarely associated with a PTH1R mutation. CONCLUSIONS: We report here that systematic clinical and radiographic observation using a diagnostic rubric is highly valuable in confirming PFE and offers a reliable alternative for accurate diagnosis.
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Receptor de Hormona Paratiroídea Tipo 1 , Enfermedades Dentales , Dentición Mixta , Exones , Humanos , Receptor de Hormona Paratiroídea Tipo 1/genética , Enfermedades Dentales/genética , Erupción Dental/genéticaRESUMEN
INTRODUCTION: Primary failure of eruption (PFE) is characterized by nonsyndromic eruption failure of permanent teeth in the absence of mechanical obstruction. Recent studies support that this dental phenotype is inherited and that mutations in PTH1R genes explain several familial cases of PFE. The objective of our study was to investigate how genetic analysis can be used with clinical diagnostic information for improved orthodontic management of PFE. METHODS: We evaluated a family (n = 12) that segregated an autosomal dominant form of PFE with 5 affected and 7 unaffected persons. Nine available family members (5 male, 4 female) were enrolled and subsequently characterized clinically and genetically. RESULTS: In this family, PFE segregated with a novel mutation in the PTH1R gene. A heterozygous c.1353-1 G>A sequence alteration caused a putative splice-site mutation and skipping of exon 15 that segregated with the PFE phenotype in all affected family members. CONCLUSIONS: A PTH1R mutation is strongly associated with failure of orthodontically assisted eruption or tooth movement and should therefore alert clinicians to treat PFE and ankylosed teeth with similar caution-ie, avoid orthodontic treatment with a continuous archwire.
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Extrusión Ortodóncica , Receptor de Hormona Paratiroídea Tipo 1/genética , Enfermedades Dentales/genética , Erupción Dental/genética , Adolescente , Adulto , Dentición Permanente , Femenino , Humanos , Masculino , Mutación , Ortodoncia Correctiva/métodos , Planificación de Atención al Paciente , Linaje , Polimorfismo de Nucleótido Simple , Anquilosis del Diente/complicaciones , Anquilosis del Diente/genética , Anquilosis del Diente/terapia , Enfermedades Dentales/complicaciones , Insuficiencia del TratamientoRESUMEN
The clinical spectrum of tooth eruption disorders includes both syndromic and non-syndromic problems ranging from delayed eruption to a complete failure of eruption. A defect in the differential apposition/resorption mechanism in alveolar bone can cause conditions such as tooth ankylosis, primary failure of eruption, failure of eruption due to inadequate arch length and canine impaction. As our knowledge of the molecular events underlying normal tooth eruption has increased, so too has our understanding of clinical eruption disorders. The recent finding that one gene, parathyroid hormone receptor 1 (PTH1R), is causative for familial cases of primary failure of eruption (PFE) suggests that other disturbances in tooth eruption may have a genetic etiology. In this report, we evaluated the current terminology (ankylosis, PFE, secondary retention, etc.) used to describe non-syndromic eruption disorders, in light of this genetic discovery. We observed that some individuals previously diagnosed with ankylosis were subsequently found to have alterations in the PTH1R gene, indicating the initial misdiagnosis of ankylosis and the necessary re-classification of PFE. We further investigated the relationship of the PTH1R gene, using a network pathway analysis, to determine its connectivity to previously identified genes that are critical to normal tooth eruption. We found that PTH1R acts in a pathway with genes such as PTHrP that have been shown to be important in bone remodeling, hence eruption, in a rat model. Thus, recent advances in our understanding of normal and abnormal tooth eruption should allow us in the future to develop a clinical nomenclature system based more on the molecular genetic cause of the eruption failures versus the clinical appearance of the various eruption disorders.
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OBJECTIVE: To test the hypothesis that mutations in the parathyroid hormone 1 receptor ( PTH1R) include effects in both primary and permanent teeth. MATERIALS AND METHODS: DNA was extracted from saliva samples of 29 patients (8 familial and 21 sporadic) who presented with clinical evidence of infraoccluded teeth, and their unaffected relatives (N = 22). Sequencing followed by mutational analysis of the coding regions of PTH1R gene was completed for all individuals (N = 29). RESULTS: Eight of 29 cases revealed a heterozygous pathogenic variant in the PTH1R gene; five of eight variants represented distinct mutations based on comparison with the dbSNP, HGMD, and ESP databases. One mutation (c.1765 T>C p.Trp89Arg) was found to segregate within a family (n = 3). In silico analyses for all variants revealed a putative pathogenic effect. A genotype-phenotype correlation was reported as defined by a functional mutation in PTH1R and corresponding effects on one or more posterior teeth only; unilateral or bilateral involvement, infraoccluded primary teeth. CONCLUSIONS: Novel mutations were reported in the PTH1R gene that included PFE-affected primary molars, thus providing the basis for using a genetic diagnostic tool for early diagnosis leading to proper management.
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Dentición Mixta , Mutación , Receptor de Hormona Paratiroídea Tipo 1/genética , Diente no Erupcionado/genética , Adolescente , Adulto , Niño , Simulación por Computador , Análisis Mutacional de ADN , Diagnóstico Precoz , Femenino , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Linaje , Diente Primario , Diente no Erupcionado/diagnóstico , Adulto JovenRESUMEN
INTRODUCTION: Posterior open bite has several possible causes, including primary failure of eruption (PFE) that affects all teeth distal to the most mesial involved tooth, mechanical failure of eruption (MFE) (primarily ankylosis) that affects only the involved tooth or teeth, and soft-tissue interferences with eruption (other). METHODS: Radiographs and other clinical records for 97 cases of failure of posterior eruption submitted for consultation were analyzed to further characterize PFE and distinguish it from MFE. RESULTS: Of the 97 cases, 38 were judged to be clear-cut PFE; 19 were diagnosed as MFE; 32 were classified as indeterminate failure because they were too young to be certain of the distinction between PFE and MFE; and 8 were placed in the "other" category. Two subtypes of PFE were observed. In type 1, eruption failure occurred at or near the same time for all teeth in an affected quadrant. In type 2, a gradient of the time of failure was present, so that some further development of the teeth posterior to the most mesial affected tooth was observed before eruption failure. A family history of eruption problems was noted in 10 of the 38 PFE subjects (26%), and a pedigree analysis was done for 4 families. This was consistent with autosomal dominant transmission. CONCLUSIONS: The distinction between PFE and MFE is clinically important because it determines whether all posterior teeth, or only individual affected teeth, will not respond to orthodontic force. Certain diagnosis often requires progress radiographs so that the pattern of eruption of teeth distal to the most mesial affected tooth can be observed.