Maxillary Apical Base Research Articles

MORPHOMETRIC PATTERNS OF MAXILLAR Y APICAL BASE VARIABILITY IN PEOPLE WITH VARIOUS DENTAL ARCHES AT PHYSIOLOGICAL OCCLUSION

Morphometric data on the structure of the craniofacial complex are reliable and diagnostically significant values that are of applied nature in terms of practical dentistry. Within this study, analysis of conebeam computed tomograms, biometric indicators of plaster models obtained from the jaws of 83 people (aged 21–35) with physiological occlusion and various types of dental, gnathic dental arches, the degree of proportion between the maxillary apical base and the inter-canine distance were identified. Depending on the dental arch type, the patients were divided into three groups. The morphometric study in the CBCT frontal plane was the distance between the canines tearing tubercles and the inter-canine distance in the apical area. The study outcomes revealed discrepancies between the calculated and actual indicators of the apical base width for all types of dental arches in people with physiological occlusion. In case of mesotrusive dental arches (incisional angle — 127–143°), the width of the apical base corresponded to the width of the dental arches between the canines, while the differences in indicators were not statistically significant. In people with retrusive dental arches (incisional angle exceeding 144°), the width of the dental arch was found to be significantly above the width of the apical bases. As far as protrusive dental arches are concerned (incisional angle below 126°), these patients featured predominance of the apical bases width over the inter-canine distance. The obtained data add to that already available in research literature regarding the relationships and dimensional features pertaining to the craniofacial complex structures, as well as have applied value in orthodontic clinical practice

Computer-Aided Planning in Orthognathic Surgery: A Comparative Study with the Establishment of Burstone Analysis-Derived 3D Norms.

Three-dimensional (3D) computer-aided simulation has revolutionized orthognathic surgery treatment, but scarce 3D cephalometric norms have been defined to date. The purposes of this study were to (1) establish a normative database of 3D Burstone cephalometric measurements for adult male and female Chinese in Taiwan, (2) compare this 3D norm dataset with the two-dimensional (2D) Burstone norms from Caucasian and Singaporean Chinese populations, and (3) apply these 3D norms to assess the outcome of a computer-aided simulation of orthognathic surgery. Three-dimensional Burstone cephalometric analysis was performed on 3D digital craniofacial image models generated from cone-beam computed tomography datasets of 60 adult Taiwanese Chinese individuals with normal occlusion and balanced facial profile. Three-dimensional Burstone analysis was performed on 3D image datasets from patients with skeletal Class III pattern (n = 30) with prior computer-aided simulation. Three-dimensional Burstone cephalometric measurements showed that Taiwanese Chinese males had significantly (p < 0.05) larger anterior and posterior facial heights, maxillary length, and mandibular ramus height than females, with no significant (p > 0.05) difference for facial soft-tissue parameters. The 3D norm dataset revealed Taiwanese Chinese-specific facial characteristics, with Taiwanese presenting (p < 0.05) a more convex profile, protrusive maxillary apical bases, protruding mandible, protruding upper and lower lips, and a shorter maxillary length and lower facial height than Caucasians. Taiwanese had significantly (p < 0.05) larger maxillary projection, vertical height ratio, lower face throat angle, nasolabial angle, and upper lip protrusion than Singaporean Chinese. No significant (p > 0.05) difference was observed between 3D norms and computer-aided simulation-derived 3D patient images for horizontal skeletal, vertical skeletal, and dental measurements, with the exception of two dental parameters (p < 0.05). This study contributes to literature by providing gender- and ethnic-specific 3D Burstone cephalometric norms, which can assist in the multidisciplinary-based delivery of orthodontic surgical care for Taiwanese Chinese individuals worldwide, including orthodontic management, computer-assisted simulation, and outcome assessment.

Is there a relationship between dental crowding and the size of the maxillary or mandibular apical base?

To determine whether apical base size is related to dental crowding. Digital scans of dental casts were taken of 75 untreated Class I adults to measure maxillary and mandibular tooth size, dental arch perimeters, intermolar widths, and intercanine widths. Cone beam computed tomography (CBCT) images were used to measure the apical base of the maxilla and mandible, including the total cross-sectional area, five basal arch perimeters and five basal arch widths. Principal components factor analyses were performed to evaluate the relationships between the apical base size and tooth-size-arch-length discrepancies (TSALD). The dental arch and maxillary apical base measures were significantly larger in males than females. There were only limited sex differences in mandibular apical base size. The dental arch measurements were smaller in subjects with greater upper and lower TSALD. Maxillary and mandibular apical base dimensions were positively interrelated. Low-to-moderate correlations were found between the size of the maxillary apical base and TSALD. The size of the mandibular apical base was not related to upper or lower TSALD. Tooth size showed little to no relationship with TSALD. Although maxillary apical base size is related to maxillary and mandibular crowding in subjects with Class I malocclusion, mandibular apical base size is not.

Identification of an Alternate Maxillary Apical Base Landmark from Pre-existing Substitution given by Different Authors

Introduction: It is often difficult to locate Point A in a lateral cephalogram due to operational errors. Faulty identification of PointA can lead to erroneous measurement and faulty diagnosis.Objective: To identify nearest alternative maxillary apical base landmark for Point A substitutions given by different authors.Materials &amp; Method: A cross sectional study was conducted on thirty good quality lateral cephalograms, which were appraisedfor skeletal Class I with the help of parameters angle ANB, WITS appraisal and Beta angle. Only those lateral cephalogramswere selected where Point A was easily identified. Landmarks: Sella (S), Nasion (N), Point A and three substitution points Y, L, Xwere traced. Angles formed by SN with Point A (Angle SNA) and three substitution points (Angle SNY, SNX, SNL) were measured.Correlation of angle SNA with angles SNY, SNX and SNL were derived.Result: A mean value of 82.8o ±1.9o, 83.1o ±1.8o, 78.3o ±2.9o and 78.7o ±2.7o for Angle’s SNA, SNY, SNL and SNX respectivelywas observed. A statistically significant correlation was observed between angles SNA and SNY, SNL, SNX; and strong positivecorrelation was observed with angle SNY.Conclusion: Point Y is the most nearing maxillary apical base landmark to Point A. Hence maxillary apical base landmark canbe substituted by Point Y where identification of point A is not obvious.

Comparison of dentoskeletofacial cephalometric values of Malwa population of Madhya Pradesh with other racial and ethnic groups

IntroductionDifferent races have different dentoskeletal morphology and pattern. What is considered aesthetic and pleasing for one ethnic group may not be considered likewise in another group. Normative data, based on a single ethnic group or race, do not represent all. This study was undertaken to study and compare the cephalometric dentofacial values of the Malwa population of Madhya Pradesh state in India and to compare the craniofacial morphology of Malwa population with other races and Indian ethnic groups. MethodsThe study sample comprised of 50 normal adult subjects (26 males, 24 females). The lateral cephalograms were analyzed with cephalometric analysis for various parameters. The mean values of all parameters were compared to four international populations and five groups of Indian ethnic origin. The 'Z′ test was applied to each parameter and the 'Z′ value and the 'p' value was determined for each parameter. ResultsStatistically significant differences were found between study population and different groups compared on certain parameters. ConclusionCompared to internationally well-acclaimed Caucasian norms, Malwa subjects had more protrusive lips, and protruded incisors. The maxillary apical base was found to be more anteriorly placed with normal or comparable mandibular apical base. Subjects exhibited horizontal growth pattern predominantly.

Maxillary expansion with the memory screw: a preliminary investigation

ObjectiveThe purpose of this study was to investigate the effects of a newly developed rapid maxillary expansion screw-the memory screw-over 6 months.MethodsFive subjects, aged between 11.7 and 13.75 years, were enrolled in this study. All subjects underwent placement of a maxillary expansion appliance containing superelastic nickel-titanium open-coil springs in its screw bed. The parents of the patients and/or the patients themselves were instructed to activate the expansion screw by 2 quarter-turns 3 times a day (morning, midday, and evening; 6 quarter-turns a day). The mean expansion period was 7.52 ± 1.04 days. Dentoskeletal effects of the procedure, including dentoalveolar inclination, were evaluated. Measurements of all the parameters were repeated after 6 months of retention in order to check for relapse.ResultsSella-Nasion-A point (SNA) and Sella-Nasion/Gonion-Menton angles increased, and Sella-Nasion-B point (SNB) angle decreased in all the subjects during the expansion phase. However, they approximated to the initial values at the end of 6 months. On the other hand, the increments in maxillary apical base (Mxr-Mxl) and intermolar widths was quite stable. As expected, some amount of dentoalveolar tipping was observed.ConclusionsThe newly developed memory expansion screw offers advantages of both rapid and slow expansion procedures. It widens the midpalatal suture and expands the maxilla with relatively lighter forces and within a short time. In addition, the resultant increments in the maxillary apical base and intermolar width remained quite stable even after 6 months of retention.

Relationship between occlusal findings and orofacial myofunctional status in primary and mixed dentition

The aim of this study was to provide basic representative data on the prevalence of malocclusions involving space deficiency in both primary and early mixed dentition and to examine the relationship between these malocclusions and orofacial dysfunctions. The results should be viewed from an orthodontic prevention and early treatment perspective. Orthodontic findings in the maxilla and mandible as well as the myofunctional status of 766 children in primary dentition and 2,209 children in mixed dentition were examined clinically in a cross-sectional study. The following parameters from each jaw were subjected to orthodontic analysis: crowding in the anterior and posterior regions of the maxilla and mandible in primary and mixed dentitions, deviations from normal maxillary arch forms in the primary dentition, deviations from normal anterior maxillary arch width in mixed dentition and maxillary apical base morphology in mixed dentition. Static and dynamic orofacial dysfunctions were documented with reference to specific parameters and clinical tests. Crowding was observed in every tenth child in primary dentition (10.8%) and in every second child in mixed dentition (49.7%). Habitual open mouth posture, visceral swallowing, articulation disorders and oral habits were statistically significantly more frequent in children in primary dentition presenting a narrow maxillary arch. Reduced anterior maxillary arch width (compression) was statistically more frequent in children in early mixed dentitions with habitual open mouth posture. A narrow maxillary apical base correlated positively with all the orofacial dysfunctions analyzed. Deviations from a regular arch form become apparent very early during dentition development and coexist with specific orofacial dysfunctions. They are thus important indicators for the early detection of functional abnormalities, causing deviations from normal dentition development. In children with orofacial dysfunctions the development of a narrow maxillary dental arch should be prevented by myofunctional therapy and by educating the parents. Interceptive orthodontic measures to treat a narrow maxillary arch in primary and early mixed dentition should also focus on eliminating functional disturbing factors, such as orofacial dysfunctions. Interdisciplinary cooperation with specialists in other fields of medicine, e.g. otorhinolaryngology and speech therapy, is essential to achieve this goal.

Effects of the functional regulator III on transversal changes: a postero-anterior cephalometric and model study

Studies assessing the transversal treatment changes caused by the functional regulator III (FR-3) are limited in number. This clinical study was planned to analyse the transversal effects of the FR-3 appliance therapy. The treatment group consisted of 17 patients (8 males and 9 females) with Class III malocclusion, who were treated with the FR-3 appliance. The control group consisted of 17 subjects (7 males and 10 females) with a normal occlusion. Mean ages of the subjects were 10.73 and 10.66 years in the treatment and control groups, respectively. Postero-anterior radiographs and stone casts were obtained before (T1) and after (T2) treatment/observation. The results of the Student's t-test comparing initial values showed that maxillary dentoalveolar and skeletal widths are significantly larger in the control group than those in the treatment group. At the end of the treatment, significant transverse increments occurred only at the dentoalveolar level of the maxilla. The transversal changes in the mandible were not statistically significant. Buccal shields of FR-3 did not stimulate the growth of maxillary apical base but caused an enhanced and supplementary widening of maxillary dental and alveolar structures.

Predictive value of morphologic parameters for successful correction of Class II Division 2 malocclusion

The aim of this study was to assess the predictive value of pretreatment cephalometric parameters and apical base size for successful correction of Angle Class II Division 2 malocclusion. Pretreatment lateral cephalograms and pretreatment and posttreatment study casts of 96 subjects with Class II Division 2 malocclusions were examined to obtain 23 cephalometric parameters and to measure the size of the apical bases. Success of occlusal correction was evaluated as the percentage of change of peer assessment rating scores during treatment; percentage of change was the dependent variable in multivariate statistical analyses used to test the predictive value of the assessed parameters. Cephalometric parameters of pretreatment craniofacial morphology were insignificant as predictors of successful orthodontic correction of the malocclusions. Maxillary apical base size was the strongest predictor of occlusal correction and might serve as a valuable diagnostic predictor of successful treatment outcome. (Am J Orthod Dentofacial Orthop 2003;123:279-85)

A retrospective study of Angle Class I malocclusions treated orthodontically without extractions using two palatal expansion methods

The correction and relapse of mandibular anterior crowding was evaluated in a population of 58 patients with Angle Class I malocclusion who were treated orthodontically without extraction of permanent teeth. The subjects were retrospectively evaluated from records taken before treatment, posttreatment, and postretention. The postretention period averaged 8 years (minimum of 4 and maximum of 20 years). All cases in Groups A and B were given orthopedic treatment to develop the maxillary apical base in the transverse and anteroposterior planes. Group A was treated with expansion of the inner bow of the face bow appliance (Kloehn), and Group B was treated with the Haas palatal expansion appliance. Both groups were then treated orthodontically with tandem mechanics. The response variables measured were: overbite, overjet, intercanine distance, intermolar distance, and irregularity index. Study groups A and B were not significantly different for subject age, retention, or postretention time. Moreover, the groups did not show significant difference for any of the response variables before treatment. However, there was a statistically significant difference in the treatment times ( P = .0133). A statistically significant treatment effect was observed for most response variables in the groups. Overbite, overjet, and irregularity index were significantly reduced, intermolar distance was significantly increased, and intercanine distance showed no significant change in Groups A and B. In the postretention period, there was a tendency for variables to change slightly toward their before treatment values but no compromise of orthodontic correction was noted. The irregularity index in Group A was corrected from 4.8 to 1.1 mm and remained at 1.1 mm in the postretention period. The irregularity index in Group B was corrected from 5.1 to 1.2 mm ( P = .0001) and changed slightly from 1.2 to 1.7 mm ( P = .0540) in the postretention period. We concluded that mandibular incisors tended to become more crowded postretention. However, in contrast to previous reports, we calculate this relapse to be small. Neither before treatment nor posttreatment variables were predictive of relapse. (Am J Orthod Dentofacial Orthop 1999;116:101-7)

A method of measuring the apical base.

The maxillary and mandibular apical base areas were measured, using a gnathograph, on the study casts of 156 adults and children representing Class II division 1, Class II division 2 and Class III malocclusions. There were significant differences between the groups at each age. The maxillary apical base areas tended to be smaller for the adults than for the children in all three occlusal classes. By contrast, the mandibular apical base areas tended to be larger for the adults than for the children, except in Class II division 1 malocclusion. Following a logarithmic transformation to stabilize the variance, regression lines were fitted to relate the size of the maxillary and mandibular apical bases to one another, for the malocclusion groups within each age group. The method gives additional information regarding the degree of apical base discrepancy in a given case, but more work is required before it can be used as a diagnostic tool.

The effects of the FR-3 appliance on the transversal dimension

The purpose of this study was to examine the effects of the FR-3 appliance on the transversal dimension. The treatment group consisted of 20 patients with Class lIl malocclusion, who were treated with the FR-3 appliance. The control group consisted of 19 patients with Class lIl malocclusion. Posteroanterior radiographs and study models were taken at the beginning and at the end of the study in both groups. The results suggested that although FR-3 appliance therapy does not increase the width of the nasal cavity and does not stimulate the growth of the maxillary apical base, it does cause an increase in the intermolar and interpremolar distances in the maxilla both in the dental and the alveolar areas. (Am J Orthod Dentofac Orthop 1996;110:55-60.)

"Wits" appraisal in southern Chinese children.

The sagittal difference between the maxillary and mandibular apical bases in orthodontic diagnosis and treatment planning can be evaluated by means of the angle ANB or alternatively, by means of the "Wits" appraisal. The lateral cephalometric radiographs of a randomly selected sample of 101 Southern Chinese children aged 10-15 years, with 55 males and 46 females were traced and analyzed by the standardized method taught to dental undergraduates. The "Wits" appraisal and angulation of the A-B line to the functional occlusal plane were added in order to generate data relevant to the local population, on whom the flatness of the nose-nasion-forehead region imposes a genuine difficulty in the identification of the cephalometric nasion. Data analyses were performed under landmark nasion. Data analyses were performed under different categories with respect to age groups, 10-12 years and 13-15 years; the types of malocclusion and sex. It was found that both the angular and linear measurements were comparable to the existing norms established for the Chinese population. The "Wits" appraisal values have to be modified in order to be applicable to this population with -4.9 millimeters and -4.5 millimeters being the normal values for male and female children respectively.

顎態模型計測による歯槽基底および歯列弓の経年的変化に関する研究 : 口蓋点を計測基準として

Using the serial gnathostatic models longitudinally taken over a period of about three years from 37 males and 32 females from 6 to 17 years of age, and using a new measuring method established in which the palatal vault was set as the standard point for measuring. The length and width of the maxilla and mandible apical bases and the dental arches, and changes in tooth inclination were examined longitudinally for four groups consisting of normal occlusion, maxillary protrusion, anterior cross bite, and crowding. Changes in maxillo-mandibular horizontal relation were also examined. Results are summarized as follows : 1. The horizontal changes with growth of point 'a', which is the anterior point of the maxillary apical base, was minimal for each group. However, the horizontal changes with growth of point 'b', which is the anterior point of the mandibular apical base, varied. As a result, the horizontal distance between the points 'a' and 'b' increased for the maxillary protrusion and decreased for the anterior cross bite. 2. The difference in the length of the dental arches between the maxilla and mandible was stable for normal occlusion, whereas the difference decreased for the maxillary protrusion and for anterior cross bite, but increased for crowding. 3. The width of the apical bases and of the dental arches increased to the age of 17 but no distinct difference was indicated between normal occlusion and malocclusion for both maxilla and mandible. 4. As to the changes in molar inclination, distal tipping decreased in the maxilla, medial tipping decreased in the mandible, and buccal tipping decreased, for each group. No significant difference was indicated between normal occlusion and malocclusion.

Tandem concept in the nonextraction treatment of Class II malocclusion

1. 1. A systematic controlled nonextraction approach in the treatment of certain Class II malocclusions exhibiting arch-length deficiencies has been presented. 2. 2. Clinical cases, diagnostic criteria for case selection, the biomechanics of this tandem force system, time sequence in tooth movement, and ways to avoid untoward sequelae have also been offered. 3. 3. The major advantages in utilizing the basic extraoral appliance and auxiliary mechanisms are as follows: 3.1. A. various groups of tooth movements are initiated in one or more areas of both dental arches simultaneously. 3.2. B. Orthodontic pressures are within physiologic limits. 3.3. C. A minimum number of bands is required. 3.4. D. Positive control of anchorage is ensured. 3.5. E. Class II mechanics is not necessary. 4. 4. In each of the four cases presented, the anteroposterior and mediolateral changes that occurred resulted in an increase in the linear length and width of the maxillary and mandibular dental arches. A sufficient increase in the maxillary apical base was also noted and may prove to be a significant yardstick in measuring the stability index of each case. 5. 5. Photographic and cephalometric evaluation revealed that the facial contour and the relative position of the mandibular incisors were not adversely affected.

Visualization of orthodontic forces during cuspid retraction

The correction and relapse of mandibular anterior crowding was evaluated in a population of 58 patients with Angle Class I malocclusion who were treated orthodontically without extraction of permanent teeth. The subjects were retrospectively evaluated from records taken before treatment, posttreatment, and postretention. The postretention period averaged 8 years (minimum of 4 and maximum of 20 years). All cases in Groups A and B were given orthopedic treatment to develop the maxillary apical base in the transverse and anteroposterior planes. Group A was treated with expansion of the inner bow of the face bow appliance (Kloehn), and Group B was treated with the Haas palatal expansion appliance. Both groups were then treated orthodontically with tandem mechanics. The response variables measured were: overbite, overjet, intercanine distance, intermolar distance, and irregularity index. Study groups A and B were not significantly different for subject age, retention, or postretention time. Moreover, the groups did not show significant difference for any of the response variables before treatment. However, there was a statistically significant difference in the treatment times (P = .0133). A statistically significant treatment effect was observed for most response variables in the groups. Overbite, overjet, and irregularity index were significantly reduced, intermolar distance was significantly increased, and intercanine distance showed no significant change in Groups A and B. In the postretention period, there was a tendency for variables to change slightly toward their before treatment values but no compromise of orthodontic correction was noted. The irregularity index in Group A was corrected from 4.8 to 1.1 mm and remained at 1.1 mm in the postretention period. The irregularity index in Group B was corrected from 5.1 to 1.2 mm (P = .0001) and changed slightly from 1.2 to 1.7 mm (P = .0540) in the postretention period. We concluded that mandibular incisors tended to become more crowded postretention. However, in contrast to previous reports, we calculate this relapse to be small. Neither before treatment nor posttreatment variables were predictive of relapse. (Am J Orthod Dentofacial Orthop 1999;116:101-7)

The development of a treatment plan in the light of one's concept of treatment objectives

1.1. A systematic controlled nonextraction approach in the treatment of certain Class II malocclusions exhibiting arch-length deficiencies has been presented.2.2. Clinical cases, diagnostic criteria for case selection, the biomechanics of this tandem force system, time sequence in tooth movement, and ways to avoid untoward sequelae have also been offered.3.3. The major advantages in utilizing the basic extraoral appliance and auxiliary mechanisms are as follows: 3.1.A. various groups of tooth movements are initiated in one or more areas of both dental arches simultaneously.3.2.B. Orthodontic pressures are within physiologic limits.3.3.C. A minimum number of bands is required.3.4.D. Positive control of anchorage is ensured.3.5.E. Class II mechanics is not necessary.4.4. In each of the four cases presented, the anteroposterior and mediolateral changes that occurred resulted in an increase in the linear length and width of the maxillary and mandibular dental arches. A sufficient increase in the maxillary apical base was also noted and may prove to be a significant yardstick in measuring the stability index of each case.5.5. Photographic and cephalometric evaluation revealed that the facial contour and the relative position of the mandibular incisors were not adversely affected.

A method for assessing the proportional relation of apical bases and contact diameters of the teeth

T HE relation of maxillary apical bases and tooth crowns to their mandibular opponents, and the relation of the base of each arch to its respective tooth crowns, is one of the most important criteria in orthodontic diagnosis and treatment planning. That there must be a harmonious relation of these factors to have esthetics and stability is generally accepted. This is true of the ideal occlusion and it is the goal we seek in orthodontic treatment. This study describes a method for measuring the apical,base easily, quickly, and accurately enough for statistical purposes. A method of determining apical base has been the principal difficulty in attempts to establish the above-mentioned relations. The mesiodistal diameters of the teeth at their anatomic contact points comprise the plane of the tooth crowns with which we are concerned. It will be referred to hereafter, for brevity, as contact diameter. The measurements of a.pical bases and contact diameters on a series of normal occlusions have been recorded to determine what their relation is. From this data, a formula has been prepared to enable a ready analysis to be made of the apical bases and contact diameters present in any case, and the amount of deviation, if any, from the normal range that must be evaluated in treatment planning. A study has been made of the results of orthodontic treatment on a variety of malocclusions with the proportional relation of (3 ) maxillary apical base to contact diameters or maxillary teeth, (2) mandibular apical base to contact diameters of mandibular teeth, (3) maxillary to mandibular apical base, and (4) contact diameters of maxillary to mandibular teeth.