•The straight-wire appliance is an individualized, fully-programmed appliance system.•The Six Keys to Normal (Optimal) Occlusion laid the foundation for straight-wire appliance.•Recent advances ...include the customization of orthodontic bracket systems using computer-aided design/computer-aided manufacturing and three-dimensional printing technologies.•Parameters of an optimal arch are defined by individual tooth positions and collective tooth positions.•A bracket set is assigned to an arch based on its interim core discrepancy.
The straight-wire appliance is an individualized, fully-programmed appliance system that has been in clinical use since the early 1970s. A study of tooth positions in individuals with naturally occurring harmonious occlusions led to the discovery of the Six Keys to Normal (Optimal) Occlusion which provided data for bracket features and prescription values incorporated into the straight-wire appliance. It was based on the notion that tooth anatomy, morphology, and optimal positions were alike enough among individuals, regardless of age, sex, or race to justify using prefabricated brackets with average prescription values. New technologies have led to advancements in appliance customization. Customized brackets can be made-to-order with one-of-a-kind prescription values and bracket base contours that fit precisely to the morphologic characteristics of the teeth. If costs and material qualities were comparable, would treatment efficiency or treatment outcomes be superior when using a customized appliance compared with a prefabricated straight-wire appliance? If not, why not?
Incisor position and alveolar bone thickness Andrews, Will A; Abdulrazzaq, Wakas S; Hunt, Jeffrey E ...
The Angle orthodontist,
01/2022, Letnik:
92, Številka:
1
Journal Article
Recenzirano
Odprti dostop
To evaluate incisor position and its relationship to alveolar bone in untreated optimal occlusions and in untreated Class II malocclusions.
Fifty-seven lateral cephalograms of individuals with ...naturally occurring optimal occlusions (mean age = 23 years) were used to assess positions of central incisors and their relationships to alveolar bone. Data were compared to a sample of 57 individuals with untreated Class II malocclusions with concurrent anterior-posterior (AP) skeletal discrepancies (mean age = 16.9 years).
Significant intergroup differences were found for AP jaw relationship, maxillary alveolar bone thickness, mandibular incisor inclination, maxillary incisor root distance to labial surface of alveolar bone, and mandibular incisor root apex distance to labial surface of alveolar bone. Small differences between females and males existed for several variables. In both samples, maxillary incisor roots were located closer to the labial surface of alveolar process than to the palatal surface by roughly a 2:1 ratio. Mandibular incisor root apices were generally equidistant from the labial and lingual surfaces of the alveolus in the optimal sample but closer to the lingual surface in the Class II sample.
Maxillary incisors tend to occupy the anterior one-third of the alveolus in untreated individuals, regardless of AP interarch dental relationships or AP jaw relationships. Mandibular incisor root apices tend to be centered within the alveolus in untreated optimal occlusions but are more positively inclined, and their root apices are more posterior in untreated Class II malocclusions.
Introduction In this study, we aimed to investigate the effect of buccolingual inclinations of the maxillary canines and premolars on the perceived attractiveness of the smile when viewed from the ...frontal perspective. Methods A smiling frontal photograph was taken of a man. A 3-dimensional digital dental model of this subject was constructed within which the buccolingual inclinations of the canines and premolars could be altered relative to the occlusal plane. Three-dimensional models of the altered digital models were then printed in resin and mounted on articulators. Frontal photos of the mounted models were taken and transferred to the smile image. A series of images was produced with the canines and premolars inclined buccally or lingually by different degrees. The smile images were assessed by 2 panels, orthodontists and laypeople. Results There was a broad range of esthetic acceptability for the buccolingual inclinations of the maxillary canines and premolars. The range of preferred inclinations was not as broad. Smile esthetics was significantly compromised ( P <0.01) when the canines were lingually inclined more than −12°, or the premolars were lingually inclined more than −15°, as perceived by orthodontists and laypersons. Buccally tipping the canines more than 6° also made the smile esthetics less satisfying ( P <0.01). Conclusions It could be esthetically satisfying to position the teeth within the ranges of 0° to −7° of inclination for the canines and −3° to −11° of inclination for the premolars, as assessed by the orthodontists, or of 3° to −10° of inclination for the canines and 5° to −11° of inclination for the premolars, as assessed by the laypersons. Clinicians could exercise flexibility within this range, when compromising tooth positions for transverse jaw discrepancies.
The purposes of this investigation were to determine the horizontal distances between the mandibular posterior teeth and the WALA ridge in a sample of Peruvians with normal occlusion and to compare ...them by tooth type, sex, arch side, and age groups.
65 dental casts of subjects with normal occlusion were collected. Posterior teeth, except for third molars, were evaluated. The horizontal distances between the occluso-gingival midpoints of the buccal surfaces (FA points) of each tooth and the WALA ridge were measured using a modified digital caliper. The values between each different tooth type within the sample were compared using the ANOVA and Scheffe tests, while comparisons by sex, arch side and age groups, using the Student's t-test.
The mean distances in the sample was 0.96 mm for first premolars, 1.45 mm for second premolars, 2.12 mm for first molars and 2.55 mm for second molars. Statistically significant differences between each of the four tooth types were found. There were no significant differences found between sex, arch side and age groups.
The horizontal distances between the mandibular posterior teeth and the WALA ridge increased progressively from the first premolars to the second molars in Peruvians with normal occlusion. The WALA ridge was a good landmark to evaluate the positions of posterior teeth in Peruvians with normal occlusion.
Built not Bought Andrews, Will
Performance research,
02/2020, Letnik:
25, Številka:
1
Journal Article
Recenzirano
This article explores the connections between amateur enthusiasm and performative display within the modified Volkswagen community in the UK. Enthusiast labour is key to performance within this ...community and through discussion of the built not bought debate, this article shows that participants distinguish between amateur and professional labour; illustrating the relative prestige placed on the former. Drawing on ethnographic fieldwork conducted within the modified VW community in the English Midlands and Mid Wales, throughout 2014 and 2015, this article argues that modified VW cars perform in three key ways: through static displays at car shows; mobile displays on public roads; and sonic performances that echo beyond the car itself. Each of these performances serves to highlight the connections between the amateur labour put into cars and their performed display within particular spaces. The article concludes by showing that modified car enthusiasts are often motivated to perform by a desire to be seen, both by the public in public motorscapes but also by audiences of their peers at car shows, who can appreciate the car as the fruit of their enthusiast labour. Conceptually, this article contributes to the intersection of enthusiasm research, understandings of amateur labour and the geographies of the car.
Built not Bought Andrews, Will
Performance research,
20/1/2/, Letnik:
25, Številka:
1
Journal Article
Recenzirano
This article explores the connections between amateur enthusiasm and performative display within the modified Volkswagen community in the UK. Enthusiast labour is key to performance within this ...community and through discussion of the built not bought debate, this article shows that participants distinguish between amateur and professional labour; illustrating the relative prestige placed on the former. Drawing on ethnographic fieldwork conducted within the modified VW community in the English Midlands and Mid Wales, throughout 2014 and 2015, this article argues that modified VW cars perform in three key ways: through static displays at car shows; mobile displays on public roads; and sonic performances that echo beyond the car itself. Each of these performances serves to highlight the connections between the amateur labour put into cars and their performed display within particular spaces. The article concludes by showing that modified car enthusiasts are often motivated to perform by a desire to be seen, both by the public in public motorscapes but also by audiences of their peers at car shows, who can appreciate the car as the fruit of their enthusiast labour. Conceptually, this article contributes to the intersection of enthusiasm research, understandings of amateur labour and the geographies of the car.
Introduction The aims of this study were to evaluate the distances between the mandibular permanent teeth and the alveolar process in Brazilians with normal occlusion and to compare them with normal ...American values. Methods We used 59 mandibular casts from untreated subjects who had permanent dentition and the 6 keys to normal occlusion. A computer program was used to calculate the distances between the dental reference points and the alveolar process for each tooth. The mean values were then compared to the normal values by applying the Student t test at a significance level of 0.05. Results The results showed a progressive increase of these distances from the anterior region (incisors) to the posterior region (molars), from 0.00 to 2.49 mm. All measurements had statistically significant differences from the American sample, except for the values for canines and first premolars. Conclusions Brazilians with normal occlusion have more lingual crown positions for the incisors, second premolars, and molars compared with Americans with normal occlusion. Although these findings were statistically significant, they are unlikely to be clinically significant.
The paper uses illustrations from rural India and Bangladesh to develop a critical analysis of practices and experiences of poverty often overlooked in development policies. It challenges the ...principle measurement, calculative rationality and static representation in anti-poverty interventions that present poverty as a 'problem' to be resolved. It draws on poststructuralist ideas to express poverty differently and shift from problem-solving to problematisation. Drawing on the concept of 'rhizome' it highlights the connectivity, heterogeneity and multiplicity of poverty. Examples from interviews and photo diaries illustrate manifold poverty as a combination of heterogeneous activities, objects and affects that complicate development ethics and challenge the logic of reason in existing policies. The paper explores improvisation, experimentation, hope and repetition as mechanisms for critically evaluating aquaculture-led development and attending to overlooked objects, uncertain outcomes and untold stories of disadvantage.
To evaluate and compare the anteroposterior relationship of the maxillary central incisors to the forehead in adult white females with harmonious profiles and in adult white female orthodontic ...patients.
Ninety-four photographic images of adult white females with good facial harmony (control sample) were compared with 94 photographs of adult white females seeking orthodontic treatment (study sample). All images were of the face in profile with the maxillary central incisors and the forehead in full view. The images were scanned, resized, and rotated to the upright head position. Reference lines were constructed to assess the anteroposterior positions of the maxillary central incisors as well as forehead inclinations.
In the control sample, 93% had maxillary central incisors positioned between the FFA point and glabella, 4% posterior to the FFA point, and 3% anterior to glabella. The positions of the maxillary central incisors were strongly correlated with forehead inclination (r2 = .642). In the study sample, 21% had maxillary central incisors positioned between the FFA point and glabella, 64% posterior to the FFA point, and 15% anterior to glabella. The positions of the maxillary central incisors were poorly correlated with forehead inclination (r2 = .094). The difference between the means for anteroposterior maxillary incisor position was statistically significant (P = .0001).
The forehead is an important landmark for anteroposterior maxillary incisor positioning for adult white female patients seeking improved facial harmony.
Editor's Summary and Q&A Triviño, Tarcila; Siqueira, Danilo Furquim; Andrews, Will A
American journal of orthodontics and dentofacial orthopedics,
2010, Letnik:
137, Številka:
3
Journal Article
Recenzirano
Introduction The aims of this study were to evaluate the distances between the mandibular permanent teeth and the alveolar process in Brazilians with normal occlusion and to compare them with normal ...American values. Methods We used 59 mandibular casts from untreated subjects who had permanent dentition and the 6 keys to normal occlusion. A computer program was used to calculate the distances between the dental reference points and the alveolar process for each tooth. The mean values were then compared to the normal values by applying the Student t test at a significance level of 0.05. Results The results showed a progressive increase of these distances from the anterior region (incisors) to the posterior region (molars), from 0.00 to 2.49 mm. All measurements had statistically significant differences from the American sample, except for the values for canines and first premolars. Conclusions Brazilians with normal occlusion have more lingual crown positions for the incisors, second premolars, and molars compared with Americans with normal occlusion. Although these findings were statistically significant, they are unlikely to be clinically significant.
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