Which premolar is the smallest

These findings are in agreement with those reported by other investigators Nie and Lin, ; Stephanie et al. Accurate diagnosis and treatment planning is important in Class II and Class III malocclusion subjects, especially females, with proportionately discrepant maxillary dental arches.

In the event of discrepancies, the appropriate treatment such as composite build-ups or mesiodistal reduction and orthodontics can be predicted more effectively Araujo and Souki, Anterior crown torque changes may be used as an orthodontic solution to correct the anterior occlusion and achieve an ideal incisor relationship. Increasing or decreasing the maxillary tooth size mass in Class III or II patients, respectively, should be considered with the objective of achieving an optimal anterior and posterior relationship of the dentition.

On the basis of the limitations of this investigation, the following conclusions can be drawn:. Maxillary canine, first premolar, second molar, and mandibular canine mesiodistal widths in the Class II male subjects were greater than those in the Class I and III males,. The upper central, lateral, first premolar, second molar, lower central, and first premolar mesiodistal widths in the Class III group were smaller than those in the Class I and Class II samples.

However, the maxillary second premolar, first molar, and mandibular canine widths in the Class II females were greater than those in the Class I and Class III females,. All mesiodistal widths were found to be statistically different according to gender dimorphism,. Google Scholar. Google Preview. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.

Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents Abstract. Subjects and methods. Maxillary and mandibular mesiodistal tooth sizes among different malocclusions in a sample of the Turkish population. Oxford Academic. Metin Nur. Select Format Select format.

Permissions Icon Permissions. Abstract The purpose of this study was to establish normative data for mesiodistal tooth crown dimensions with respect to malocclusions and gender differences in Turkish sample. Table 1 Mean and standard deviation SD of the mesiodistal crown size of individual teeth for malocclusion groups and the results of one-way and univariate analysis of variance ANOVA.

Open in new tab. Bolton anterior tooth size discrepancies among different malocclusion groups. Google Scholar PubMed. Google Scholar Crossref. Search ADS. The prediction and evaluation of final occlusal relationship in case of lower incisor extraction or missing. Mandibular incisor extraction treatment of a Class I malocclusion with Bolton discrepancy: a case report.

Disharmonies in tooth size and its relation to the analysis and treatment of malocclusions. Maxillary and mandibular tooth size in different racial groups and in different occlusion categories. Comparison of intermaxillary tooth size discrepancies among different malocclusion groups.

Univariate versus multivariate differences in tooth size according to sex. All rights reserved. For permissions, please email: journals. Issue Section:. Download all slides. The mesial outline of the crown is slightly convex from cervix to the point where it joins the mesial slope of the buccal cusp.

The distal outline is more convex than the mesial outline. The cervical outline on buccal view is slightly convex and curves in an apical direction. The tooth is thicker at the cervical portion than the maxillary first premolar. The cusp tip is offset to the mesial; hence, the mesio-occlusal slope of the buccal cusp ridge is slightly shorter than the disto-occlusal slope.

The opposite is true for the first premolar. The buccal ridge of the crown may be less prominent than that of the first premolar. The crown of the maxillary second premolar has a trapezoidal form at the lingual aspect. From the lingual view, little variation can be seen except that the lingual cusp is almost having the same length as the buccal cusp. In addition, the lingual cusp tip is not quite so far offset to the mesial.

The cervical outlines of the crown at this aspect present that the cervical line is less curved apically than the buccal view.

The occlusal outline is formed by the lingual cusp tip and its cusp slopes. The mesial aspect shows the difference in cusp length between the first and second premolars. The cusps of the second premolar are shorter, with the buccal and lingual cusps more nearly the same length.

Greater distance between the cusp tips widens the occlusal surface buccolingually. Developmental depressions are not seen on the mesial surface of the crown as on the first premolar. The crown surface is convex. A shallow developmental groove appears on the single tapered root.

There is no canine fossa or canine groove on this surface. The more equal size of the cusps is also noted. Both the contact area and marginal ridge are found at a slightly more cervical level than on the mesial of the first premolar. The distal view of the second premolars has the same features with the first premolars.

Since the distal contact of second premolar is with the first molar, the contact area is slightly larger in size, when compared to the first premolar.

Both the distal contact area and marginal ridge are located at a slightly more cervical level than on the distal of the first premolar. The distal root depression is deeper than the mesial depression on the maxillary second premolar.

The schematic description of occlusal table is given in Figure 5. The outline of the crown of the second premolar is more rounded or oval rather than hexagonal shape at this aspect. However, there may be some exceptions about this form. More distance between the cusp tips buccolingually than on the first premolar may be noted. Hence, the lingual cusp is almost as wide as the buccal. The grooves are shorter, shallower, and more irregular than in the first premolar.

The central developmental groove is also shorter and more irregular. This groove has numerous supplementary grooves radiating from the central groove. This arrangement gives the occlusal surface a more wrinkled appearance. The schematic description of occlusal table of the maxillary second premolar tooth. The crown and root variations of the maxillary second premolar teeth.

The root is usually single and shows a longitudinal groove on the mesial and distal surfaces, but may occasionally be double. Root length is normally as great, or slightly greater than the root structure of the first premolar.

The root is wider buccolingually than mesiodistally. It is often deflected slightly to the distal in its apical portion. The average measurements of the maxillary second premolar are shown in Table 4. The average measurements of the maxillary second premolar teeth.

Variations: The crown and root of this tooth also exhibit variations and anomalies Figure 6. Chronologic development of the permanent mandibular first premolar is given in Table 5. The image of mandibular first premolar from all aspects is given in Figure 7.

Mandibular first premolar tooth from different aspects. The mandibular first premolar is similar to a mandibular canine and second premolar from buccal aspect. It has nearly same buccolingual measurement as a canine and has a sharp buccal cusp.

The occlusocervical dimension of this tooth is less than all anterior teeth. However, this dimension is greater than that of the second premolar or any molar.

The buccal surface of mandibular first premolar is convex both occlusogingivally and mesiodistally. The crown is inclined lingually, and therefore, the tip of the buccal cusp is situated on the vertical axis of the root. The buccal height of contour is in the cervical third level of the surface. There is well-developed middle buccal lobe buccal ridge between the developmental depressions in mesiobuccal and distobuccal sides. The mesial cusp ridge is shorter than the distal cusp ridge.

The contour of the mesial margin is concave from the contact area to the cervical line joining the mesio-occlusal slope to create the mesio-occlusal angle. The outline continuing from the contact area to the cusp is convex. The height of contour mesial contact area is in the middle third at the center of the crown cervico-occlusally. The distal margin is slightly shorter than mesial margin.

In addition, the outline is concave from the contact area to the cervical line and the contact area is broader than the mesial contact area. The height of contour distal contact area is approximately at the same level with the mesial contact area.

The buccal cervical line is slightly curved toward the apex and in comparison with the anterior teeth; the depth of curvature is less than that of the anterior teeth.

The buccal cusp tip divides the occlusal outline into two portions, the mesio-occlusal and disto-occlusal slopes, or mesial and distal cusp ridges. The disto-occlusal cusp ridge is longer than mesio-occlusal, moving the sharp cusp tip toward the mesial. Besides, both of the ridges are slightly concave. Since the lingual cusp is smaller and shorter than buccal cusp, the buccal section of the occlusal surface could be seen from the lingual aspect.

In addition, the crown is narrower mesiodistally on the lingual surface than on the buccal surface. Therefore, most of the mesial and distal parts could be seen from this aspect. This surface is convex in all directions and no ridge is present as seen on the buccal aspect. The lingual height of contour is in the middle third level of the surface. The most characteristic feature of this tooth is the mesiolingual developmental groove between mesial marginal ridge and lingual cusp.

Since the lingual surface is shorter than buccal surface, both margins are shorter in lingual surface than buccal surface. Different from other teeth, mesial marginal ridge of mandibular first premolar teeth is shorter than distal marginal ridge. Additionally, mesial contact area is more cervically located than distal contact area. The lingual cervical line is slightly curved toward the apex and narrower than buccal cervical line. The lingual cusp tip and ridges are approximately at same level with the occlusal surface.

Both of cusp tips are mesially offset, and the lingual cusp tip is in alignment with the buccal triangular ridge. There are mesial and distal occlusal fossae on each sides of occlusal surface.

Similarly with all the mandibular posterior teeth, the crown is in rhomboidal shape from the mesial aspect. While the buccal cusp is centered over the root, the lingual cusp tip is aligned with the lingual border of the root. The buccal outline is convex starting from the cervical line to the buccal cusp tip. In addition, the height of contour is in the cervical third of the crown. When compared with the buccal outline, this outline has more convexity.

This margin is shorter than buccal margin. The lingual height of contour is at the middle third of crown. The cervical line is slightly curved about 1 mm toward the occlusal surface. The occlusal outline is a concave arc inclining lingually. Similarly with the mesial aspect, the crown is in rhomboid shape. While there is no distolingual developmental groove, there is a distal marginal groove in this aspect of mandibular first premolar.

The cervical line on the distal surface has less curvature than mesial cervical curvature less than 1 mm. The distal contact area is wider than the mesial contact area, since the contact tooth is second premolar. The distal marginal ridge is not sloping lingually as the mesial. It is in a horizontal position, making the ridge perpendicular to the long axis of the tooth. It is located more occlusally than mesial marginal ridge.

The schematic description of the occlusal table is given in Figure 8. The shape of the crown is rhomboid or like a diamond. Since the crown is lingually inclined, from this aspect, most of the buccal surface could be seen.

The difference between buccolingual and mesiodistal dimension is approximately 0. The cusp tip is in the mesial half, and therefore, the distal half is a little bit larger than the mesial half. The schematic description of the occlusal table of the mandibular first premolar tooth. The crown and root variations of the mandibular first premolar teeth. The buccal margin has a pronounced convexity. This outline is also convex.

However, it is shorter than the buccal outline. It continues up to the mesiolingual developmental groove. The convexity of the distal outline is more apparent than the mesial outline.

It forms a right angle where it meets with the distobuccal cusp ridge. Mandibular first premolar has two cusps, a buccal and a lingual. The buccal cusp is the functional cusp, and it is larger than the lingual cusp. Additionally, the buccal cusp tip is slightly mesial to the center and located at the buccal half of the occlusal surface.

The lingual cusp is very small and is like a tubercle. It is the nonfunctional cusp as it is a mandibular tooth. The crown converges lingually. Mesial marginal ridge is shorter and is interrupted by mesiolingual developmental groove. The distal marginal ridge is more prominent and joins with the distolingual cusp ridge. They are boarded by the transverse ridge, the marginal ridges, and the mesial and distal cusp ridges of the two cusps. While the mesial fossa is linear in shape with the mesial developmental groove, the distal fossa is more circular.

In general, a mandibular first premolar has a single and straight root with a sharp apex. The root tapers from cervical to the apical region and is often curved distally. Rarely, a buccal and a lingual root or two buccal and one lingual root are present.

The buccolingual section is wider than mesiodistal section. The height of contour of buccal surface is in the center of the root. The root is approximately 3 or 4 mm shorter than that of the mandibular canine. From the mesial aspect, the root is in a tapered form from the cervical line to the apical region.

Despite the convexity in mesial and distal surfaces, longitudinal grooves are present in these surfaces, mostly deepest one in the mesial surface. The lingual surface is much narrower than buccal surface allowing most of the mesial and distal surfaces of the root to be seen.

The convexity of distal surface is more prominent than mesial surface. The average measurements of the mandibular first premolar are shown in Table 6. The average measurements of the mandibular first premolar teeth. Variations: The crown and root of this tooth exhibit some variations Figure 9.

Chronologic development of the mandibular second premolar is given in Table 7. The image of mandibular second premolar from all aspects is seen in Figure Mandibular second premolar tooth from different aspects.

The mandibular second premolar is the fifth permanent tooth from the median line in the mandibular arch, located between the mandibular first premolars and first molars. Since the occlusal table is broader and similar to that of posterior teeth, this tooth has a function more like a molar.

Despite the similarities in general form of the second premolar with the first premolar, there are differences between them except buccal surface.

Considering the buccal aspect, a mandibular second premolar has a larger crown and longer root than first premolar. The buccal cusp is not so long and not as sharp as first premolar. The cusp tip is approximately at the center of the tooth in mesiodistal direction, therefore the distobuccal and mesiobuccal slopes are equal in dimension.

The buccal surface is convex. Furthermore, mesial and distal outlines are convex except near the cervical region. The mesiobuccal and distobuccal cusp ridges are not angulated too much. Social Studies.

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