Selection of criteria for assessment of occlusal acceptability

There is no general agreement on criteria that could be applied to distinguish between orthodontically acceptable and non-acceptable occlusions after the completion of dental development. The aim of the present study was to analyse morphological and functional features that could be used as an index to define an acceptable occlusion in young adults. Three expert panels representing specialists in orthodontics and stomatognathic physiology participated in a modified Delphi method. Each panel responded to a questionnaire concerning the usefulness of various occlusal features, and a set of characteristics was selected on the basis of the responses; thereafter, applicability of the chosen characteristics and their cutoffs for an acceptable-non-acceptable dichotomy was tested clinically. To obtain a consensus level of 100%, the last panel session was completed with a group discussion. Assessments made using the morphological criteria were compared with those made with the dental health component of the Index of Orthodontic Treatment Need. The selected morphological characteristics consisted of overjet, overbite, canine relationship, crossbite, scissors bite and midline deviation. The functional evaluation comprised assessments of discrepancy between the centric relation and the intercuspal position, working- and non-working-side contacts and protrusion contacts. The dental health component and our morphological criteria showed different sensitivity to contact point displacements, interdigitation in buccal segments and increased overbite. This study provides a set of morphological and functional indicators reflecting the current consensus opinion of Finnish professionals. Further studies are needed to analyse the reproducibility of assessment of the characteristics included.     

Occlusal status in orthodontically treated and untreated adolescents

In order to evaluate the outcome of orthodontic care, all available 16-year-old adolescents (n = 138) living within the catchment area of one Finnish health center were invited for a clinical examination. A total of 126 adolescents participated, corresponding to 79% of the whole age cohort. Of these, 47% had been treated orthodontically, 2% were still wearing appliances, and 51% were untreated. In 80% of cases, a non-extraction treatment was carried out. All occlusions were evaluated using a recently developed occlusal morphology and functional index (OMFI) based on assessment of 6 morphological and 4 functional traits which are classified applying an acceptable-non-acceptable dichotomy. The occlusal status in untreated individuals was used as a second reference in comparisons between the treated and untreated occlusions. The morphological criteria for an acceptable occlusion were met by 42% of the participants and the functional criteria by 64%. Although the treated occlusions failed to meet the criteria of morphological acceptability more often than the untreated ones (73% vs 40%), the proportions of non-acceptable occlusions were fairly high among untreated occlusions. The main reasons for non-acceptability were the failure of the canine relationship, overbite, and protrusion movement to fulfill the criteria of acceptability. Only 19% of the adolescents had occlusions classified as acceptable, both morphologically and functionally. In the evaluated health center, the allocation of resources resulted in a high coverage of orthodontic care. However, our results indicate that the general occlusal status in the examined age cohort did not reach an optimal level.     

Morphological, functional and aesthetic criteria of acceptable mature occlusion.

At present, there are no generally accepted criteria that could easily be applied to the evaluation of occlusal acceptability in clinical examinations at population level. The present study analyses the opinions of Finnish orthodontists and general practitioners on the characteristics required for acceptable occlusion in the full permanent dentition. A questionnaire was sent to all 37 health centres where at least one orthodontist was employed, 31 regionally comparable health centres without an orthodontist, 12 private orthodontists, and 13 orthodontists working at university dental clinics. Seventy-four orthodontists returned the questionnaire giving a response rate of 80 per cent. They were asked to give their views on the importance of morphology, function, long-term stability, and dental appearance as elements of acceptable occlusion. They were also encouraged to indicate other significant characteristics and requested to assess the relative significance of these features. In general, the respondents expressed the need to assess morphological, functional and aesthetic aspects of occlusion as a whole. Good function, rather than morphology, was considered to be the most important feature of an acceptable occlusion, with a relative significance of 40 per cent (range 20-90 per cent). According to the respondents, the acceptability of occlusion is determined not only by morphological features, but also by the functional status and long-term stability, as well as by the patient's opinion of the dental appearance.     

Tooth contacts in eccentric mandibular positions and facial morphology.

Correlations between facial morphology and tooth contacts in excursive mandibular positions were studied in 75 men aged 20 to 33 years. The morphology of the dentition was verified on dental casts and the face was measured by use of roentgen cephalometry. No correlation was observed between facial morphology and the number of tooth contacts in the retruded position; however, wide dental arches and jaws displayed many contacts on protrusion. Numerous contacts on the functional side in group function were noted in individuals with a facial morphology associated with distal occlusion, such as Angle class II, division 1. Wide dental arches were associated with multiple functional-side contacts whereas tooth contacts on the nonfunctional side were related to the inclination of the mandible. A "long-face" morphology was related to contacts on the nonfunctional side. There was a negative correlation between the extent of the overbite (vertical overlap) and the number of tooth contacts on the nonfunctional side.     

A clinical minimum data set for primary dental care.

OBJECTIVE: To achieve consensus within primary dental care on the contents of a clinical minimum data set to measure oral health status. DESIGN: Using the Delphi process a simple random sample of 30 LDCs and 10 CDS services in England were asked to rank a list of existing clinical indicators in order of their perceived importance as a means of measuring oral health. A nominated panel representing the stakeholder organisations of primary dental care reviewed this ranking and identified a core group of clinical indicators to be included in a clinical minimum data set. RESULTS: An 80 percent response rate to the Delphi process was achieved. Consensus was reached on a core group of 10 indicators, which can provide information on patient's perceptions of pain, function and appearance, and professional measurements of caries, teeth present, periodontal disease, oral sepsis, presence of mucosal pathology and tooth wear. CONCLUSIONS: A representative sample of primary care dentists in England and the key representative organisations of primary dental care achieved consensus on the contents of a clinical minimum data set to record oral health status in primary dental care. This is a first step in standardising the measurement of oral health status across primary care.     

The relationship between the incisor position and lingual surface morphology in normal occlusion

This study aimed to investigate the relationship between the morphological characteristics of maxillary incisors and the anterior occlusion. The study materials comprised dental casts and lateral cephalograms of 26 modern Mongolian females with Angle Class I normal occlusion (mean age, 21 years 5 months). Computed tomography (CT) images of the dental casts were taken with an X-ray micro-CT system (SMX-100CT, Shimadzu, Kyoto Japan). The thickness of the marginal ridges and incisal edges, and the overjet and overbite, was measured on the three-dimensional images of the dental casts. On the lateral cephalogram, maxillary incisor to sella–nasion plane angle (U1 to SN angle), maxillary incisor to nasion-point A plane distance (U1 to NA distance), mandibular incisor to nasion-point B plane distance (L1 to NB distance), incisor mandibular plane angle, and interincisal angle were measured by tracing the left incisors of the maxilla and mandible. Spearman’s single rank correlation coefficients were used to investigate any correlation between measurement items for each maxillary incisor. The thickness of the marginal ridges and incisal edges was positively correlated with the overbite. The thickness of the incisal edges was positively correlated with the irregularity index of the maxilla. There were significant negative correlations between overbite and U1 to SN angle, U1 to NA distance, and L1 to NB distance. Significant positive correlations were noted between the overbite and the overjet. In conclusion, there was no strong relationship between the morphological characteristics of maxillary incisors and the anterior occlusion.     

正畸治疗中磨牙的拔除与保留(八)——主动拔除第一磨牙的可行性探讨

目的：分析正畸治疗中拔除第一磨牙的临床意义,着重从功能上探讨主动拔除第一磨牙矫治部分错殆畸形病例的可行性。方法：本组34份病例来源于福州第八医院7例、林连桥齿科诊所27例,均涉及拔除第一磨牙进行矫治的错殆畸形患者,男13例,女21例。年龄11～28岁,平均15,4岁,其中AngleⅠ类13例,AngleⅡ类8例,AngleⅢ类13例。均采用方丝弓矫治器进行矫治。结果：矫治完成时间12～25个月,平均18.1月。矫治后牙齿排列整齐,无间隙,前牙覆黯,覆盖正常,后牙呈牙尖交错殆关系,面部侧貌协调,咬合功能良好。结论：本着健康、功能、稳定和美观的原则,正畸中对部分病例设计主动拔除第一磨牙矫治方案是可行的。     

Follow-up study of functional and morphological malocclusion trait changes from 3 to 12 years of age

The aim of this study was to evaluate morphological and functional malocclusion trait changes in 3- to 12-year-old children and to determine whether such functional traits at the 3, 4, and 5 years of age correlated with malocclusion severity score at 12 years of age. Two hundred and sixty-seven children (132 boys, 135 girls) were randomly selected for a follow-up study from a previous cohort of 560 subjects. Functional and morphological traits were clinically assessed. Five functional malocclusion traits: mouth breathing, atypical swallowing, thumb, pacifier sucking, and bottle feeding were assessed and evaluated. Intra-arch assessment involved measurements of incisor crowding, rotation of incisors, and axial inclination of the teeth. For inter-arch measurements, overbite, anterior open bite, overjet, reverse overjet, anterior crossbite, and buccal segment relationships were recorded. The weighted sum of recorded occlusal traits thus represented the total malocclusion severity score. The median morphological malocclusion severity score was almost the same at 3 and 12 years of age, while functional malocclusion decreased. Sucking habits (finger- or dummy-sucking, bottle feeding) until 5 years of age were statistically significantly correlated with an atypical swallowing pattern from 6 to 9 years (Spearman r = 0.178, P = 0.017), which in turn was statistically significantly correlated with the morphological malocclusion severity score (Spearman r = 0.185, P = 0.042) at 12 years of age. At an early age, the morphological severity score is related to the stage of dental development, while at a later period, malocclusion severity score is also the result of incorrect orofacial functions at an early stage of dental development.     

FDI World Dental Federation: clinical criteria for the evaluation of direct and indirect restorations—update and clinical examples

In 2007, new clinical criteria were approved by the FDI World Dental Federation and simultaneously published in three dental journals. The criteria were categorized into three groups: esthetic parameters (four criteria), functional parameters (six criteria) and biological parameters (six criteria). Each criterion can be expressed with five scores, three for acceptable and two for non-acceptable (one for reparable and one for replacement). The criteria have been used in several clinical studies since 2007, and the resulting experience in their application has led to a requirement to modify some of the criteria and scores. The two major alterations involve staining and approximal contacts. As staining of the margins and the surface has different causes, both phenomena do not appear simultaneously. Thus, staining has been differentiated into marginal staining and surface staining. The approximal contact now appears under the name “approximal anatomic form” as the approximal contour is a specific, often non-esthetic issue that cannot be integrated into the criterion “esthetic anatomical form”. In 2008, a web-based training and calibration tool called e-calib () was made available. Clinical investigators and other research workers can train and calibrate themselves interactively by assessing clinical cases of posterior restorations which are presented as high-quality pictures. Currently, about 300 clinical cases are included in the database which is regularly updated. Training for eight of the 16 clinical criteria is available in the program: “Surface lustre”; “Staining (surface, margins)”; “Color match and translucency”; Esthetic anatomical form”; “Fracture of material and retention”; “Marginal adaptation”; “Recurrence of caries, erosion, abfraction”; and “Tooth integrity (enamel cracks, tooth fractures)”. Typical clinical cases are presented for each of these eight criteria and their corresponding five scores.     

Relationship between dental size and normal occlusion in Brazilian patients

The present study was performed on dental casts and lateral cephalometric films of 30 Caucasian Brazilian individuals (15 males and 15 females) aged 18 to 27 years and 4 months, all presenting normal occlusion and satisfactory facial profile. The aims were to investigate the existence of dental discrepancies according to Bolton's criteria, to obtain mean values for overbite, overjet, curve of Spee and interincisal angle, and to demonstrate any correlation among these parameters. A single calibrated operator measured each variable characteristics and the process was recorded twice with an accurate modified digital caliper. It was observed that the sample of normal occlusion did not present any dental discrepancy among the 12 teeth of opposite arches. The overall ratio (91.46) and anterior ratio (77.83) were in accordance with those proposed by Bolton. The mean values for normal occlusion in this Brazilian sample were defined as: 2.45 mm for overbite; 1.92 mm for overjet; 1.01 mm for curve of Spee and 129.57 degrees for interincisal angle. A statistically significant correlation was found between overjet and overbite.     

深覆分类与治疗方法进展

[提要] 深覆是临床常见错类型,然而其矫治确是临床一大难点。本文从深覆形成机制角度出发,根据国内外相关研究,针对牙性深覆和骨性深覆的特点、头影测量及治疗方法做一综述,以期为临床提供参考。     

A case report of adult skeletal mesio-occlusion

The patient was a 22-year-old female with a class III malocclusion characterized by maxillary constriction, dental crowding and mandibular protrusion. The treatment goals which were related to the chief complaints included correction of negative overjet, negative overbite, and dental alignment. Since the pre-existing crowding created some severe problems and prevented adequate posterior repositioning of the mandible and anterior teeth, extraction of the four first premolars were recommended to correct the overjet. This treatment resulted in greater posterior repositioning. The treatment was divided into three stages: 1) extraction of first premolar teeth, alignment, space closure and an increase in the overjet and overbite, 2) arch alignment and detailing of the occlusion with a full fixed appliance, and 3) retainers. At the end of the treatment, the patient had an acceptable dental alignment with a class I molar relationship and an improvement in facial appearance.     

Quantitative description of overjet and overbite and their relationship with the craniofacial morphology.

OBJECTIVES: 1) To define the sagittal and vertical characteristics of anterior teeth in adults with normal occlusions; 2) to explore a relationship between the overbite and overjet; and 3) to relate overbite and overjet to the skeletal pattern. DESIGN: Prospective data collection. SETTING AND SAMPLE POPULATION: Ninety-two adult dental students from the Aristotle University of Thessaloniki (49 females and 43 males) with naturally occurring Class I occlusions. EXPERIMENTAL VARIABLE AND OUTCOME MEASURES: Cephalometric data were collected for overbite, overjet, and skeletal relationships. These were then correlated for potential association between front teeth and vertical and horizontal skeletal relationships. RESULTS: The overjet measures were equally distributed among men and women, but overbite was higher in women. Facial proportions were also bigger in men, but the Mediterranean face was bigger than Northern American Caucasian. The mandibular plane angle could be associated with either increased or decreased overjet and overbite. CONCLUSION: The overbite and overjet features of an occlusion cannot be predictably associated with any particular craniofacial pattern.     

Predicting the outcome of twin block functional appliance treatment: a prospective study

A prospective study was undertaken to investigate the relationship between various measured pre-treatment parameters and the reduction in overjet achieved when using a twin block functional appliance. Forty-three subjects were fitted with a twin block functional appliance, and a number of pre-treatment clinical and radiographic morphological features were recorded. The functional appliance wear was monitored for 6 months and any individual who did not co-operate with wear was excluded from the subsequent analysis. Multiple regression analysis with stepwise inclusion was used to relate the percentage reduction in overjet achieved by functional appliance wear to any of the pre-treatment parameters. The data from 22 individuals was included in the final analysis. The overbite and SNB angle were the most strongly related variables to percentage reduction in overjet. These were then used to construct a predictive equation for the expected percentage reduction in overjet: Percentage reduction in overjet in 6 months = 132 + 4.9x1 - 1.4x2, where x1 = overbite and x2 = SNB. The pre-treatment overbite was, in isolation, the most influential feature in predicting the percentage of overjet reduction.     

Occlusal stability in shortened dental arches

Shortened dental arches consisting of anterior and premolar teeth have been shown to meet oral functional demands. However, the occlusal stability may be at risk as a result of tooth migration. The aim of this nine-year study was to investigate occlusal stability in shortened dental arches as a function over time. Occlusal stability indicators were: 'interdental spacing', 'occlusal contacts of anterior teeth in Intercuspal Position', 'overbite', 'occlusal tooth wear', and 'alveolar bone support'. Subjects with shortened dental arches (n = 74) were compared with subjects with complete dental arches (controls, n = 72). Repeated-measurement regression analyses were applied to assess age-dependent variables in the controls and to relate the occlusal changes to the period of time since the treatment that led to the shortened dental arches. Compared with complete dental arches, shortened dental arches had similar overbite and occlusal tooth wear. They showed more interdental spacing in the premolar regions, more anterior teeth in occlusal contact, and lower alveolar bone scores. Since the differences remained constant over time, we conclude that shortened dental arches can provide long-term occlusal stability. Occlusal changes were self-limiting, indicating a new occlusal equilibrium.     

A 57-year Follow-up Study of Occlusion

OBJECTIVES: To analyze changes in occlusion between the ages of 8 and 65 years in persons with a deep overbite at the age of 8 who did not receive orthodontic treatment. To describe their experiences regarding their own dentition as well as their opinions on dental esthetics and oral health. To compare these findings with those of the Normal Occlusion (N-Group) described in Part 1. SUBJECTS AND METHODS: With one exception, the 20 persons in our cohort had not undergone orthodontic therapy. Our documentation was based on intraoral photographs taken at the two time points in addition to an interview and facial photos at the age of 65. RESULTS: The overbite could be evaluated in 16 persons. In four persons various degrees of mucosal indentations in connection with the overbite had been registered. The average number of missing teeth was 3.4, compared to 1.6 in the N-group. All participants reported their oral health to be good or excellent and, similar to the N-group, nearly all considered dental esthetics to be important. CONCLUSION: The overbite had decreased during the observation period in nine, increased in five, and remained stable in two persons.     

Oral manifestations of HIV infection. Definitions, diagnostic criteria, and principles of therapy. The U.S.A. Oral AIDS Collaborative Group.

A set of definitions and diagnostic criteria for the more common oral features of human immunodeficiency virus infection were prepared as the result of a consensus reached by a group of dental and medical clinicians, epidemiologists, and other experts. These are intended for use in epidemiologic surveys, where the presumptive diagnoses are recommended, and in clinical care, pathogenesis and therapy studies, where the definitive diagnoses are appropriate.     

The compensatory mechanism in high-angle malocclusions: a comparison of subjects in the mixed and permanent dentition

Dentoskeletal morphology was assessed in 191 untreated and unselected children with a hyperdivergent (high-angle) mandibular plane (ML/NSL > or =40 degrees) by analyzing lateral roentgenographic cephalograms. The subjects were divided into mixed dentition and permanent dentition groups, and further divided into subgroups based on the amount of overbite (OB) as a measure of dentoalveolar compensation of jaw base hyperdivergency: OB < 0 mm (openbite) = insufficient/no compensation; OB 0 to 4 mm (normal overbite) = acceptable compensation; OB > 4 mm (deepbite) = overcompensation. Openbite was observed in 20% of the children, normal overbite in 50%, and deepbite in 30%. Skeletally, the deepbite mixed dentition group was characterized by a relatively posterior inclination of the maxilla, while the deepbite permanent dentition group had a relatively anterior inclination of the mandible. Dentoalveolar compensation was accomplished by relative increases in maxillary and mandibular anterior dentoalveolar heights in the mixed dentition group and by relative decreases in maxillary and mandibular posterior dentoalveolar heights in the permanent dentition. Positive overbite was found in the majority (80%) of children with high-angle morphology. Thus, mandibular hyperdivergency is frequently compensated for. Skeletal characteristics and dentoalveolar compensatory mechanisms differ with dental maturity and seem to be influenced by mouth breathing and other oral habits.     

The relationship between static occlusion and functional occlusion in a dental school population

The relationship between static occlusion and functional occlusion was evaluated in 101 dental and dental hygiene students. The sample was selected from a population of 467 students who were enrolled at one dental school during the 1987-1988 academic year based upon the following criteria: age range 18 to 32 years; caucasian race; no prior orthodontic treatment; at least 28 natural teeth present; no occlusal adjustments; and no large restorations, crowns or bridges. Fifty-two (52) of the subjects possessed "normal" static occlusion, 26 had a Class I malocclusion, 16 were found to have a Class II malocclusion, and 7 had a Class III malocclusion. The majority (i.e., 75%) of the 101 subjects possessed non-working (balancing) functional contacts. Seventy-five (75) of the subjects possessed balanced occlusion, nine had canine-protected occlusion, nine possessed group function occlusion, and eight had mixed canine-protected/group functional occlusion. This study found no statistically significant relationship between static occlusion and functional occlusion, however, there was a trend for balanced occlusion to be more often associated with "normal" (ideal) static occlusion.