INDIAN DENTAL ACADEMY
Leader in continuing dental education www.indiandentalacademy.com
Presenter: Dr.G.Hanmanth Reddy
Co-Authors: Dr. Sumant Goel
Dr. Kartik S.
BO LTO N ANALYS IS :REVIS ITED www.indiandentalacademy.com
In tro d u c tio n
Correct alignment of the teeth is a fundamental goal of orthodontic
therapy. Thus, the amount of discrepancy between the total tooth material i.e. (mesiodistal width) present and the dental arch perimeter available to accommodate the teeth is probably the most critical estimate of any of the orthodontic diagnostic procedure.
G.V.Black conducted one of the first investigations to be made in the field of tooth size. Young in 1923 compared two similar occlusions but found that the cases differed considerably in the amount of anterior over bite present. www.indiandentalacademy.com
In 1952 Wayne A. Bolton proposed intermaxillary ratios analysis designed for the purpose of localizing discrepancies in tooth size and in1958 he published condensed form of original tooth size analysis study, from which ratios and their means were presented.
•The Bolton’s ratio has been extensively used in orthodontic diagnosis for improved treatment outcome.
•The measurement as error of half an mm in the total sum of either www.indiandentalacademy.com
upper or lower width will affect the Bolton’s index approximately 1%
•Tooth size ratios described by Bolton were different in different racial groups and order was Negroids > Mongoloids>Caucasoid. However a little data in relation to degree and correct axial inclination of incisors and canines was present till today. (Qiong Nie and Jiuxiang AJO 1999)
•The thickness of the incisal edge also been mentioned but, without any quantitative assessment. The most influential factor seems to be the incisal edge thickness, were 1mm change may effect the Bolton’s index by as much as 5%(Demetrios J. Halazonetis AJO 1996). www.indiandentalacademy.com
• It is important to determine the amount and location of tooth size discrepancy before starting orthodontic treatment because most of the patients with inter arch tooth size discrepancy require either removal or addition of tooth structure.
•In our several of our clinical cases we found mismatch between overall & anterior ratios. It was found difficult to attain ideal ratios at the end of the treatment. So we carried out a study to critically evaluate the Bolton’s analysis. www.indiandentalacademy.com
Review Of Literature
Wayne A. Bolton (1958):In his study he analyased the tooth size analysis from which ratios and their means were presented.
sum of mandibular 12
* 100 =
over all ratio
sum of maxillary 12 Mean is 91.3%
sum of mandibular 6
* 100 =
sum of maxillary 6 Mean is 77.2%
He concluded that clinical significance of the analysis will
George W.Huckaba (1964) : He conducted a study on mixed dentition analysis and concluded that if the existing dental occlusion is favorable with adequate space, then periodic examination to follow the course of growth and development to ensure a favorable adult dental occlusion is possible.
John M Doris et al (1981) : In their study they concluded that the total mesio distal tooth size iswww.indiandentalacademy.com uniformly larger in crowded arches when
John E Freeman et al (1996) : Conducted a study to evaluate the percentage of orthodontic patients with a significant tooth size discrepancy and concluded that, a large number of patients presenting for orthodontic treatment possess a Bolton tooth size discrepancy which may influence treatment goals and results.
www.indiandentalacademy.com Qiong Nie and Jiuxiang (1999) : In there study they concluded that
Stephanie S .Smith et al (2000) : Conducted a study to evaluate the Bolton's interarch ratio among populations and gender and concluded a significant difference in overall, anterior and posterior interarch ratio between Whites, Blacks and Hispanics .
Aims and Objectives
1. To critically evaluate the Boltonâ€™s analysis.
2. To compute and evaluate anterior and posterior ratios separately.
Criteria for selection -Fully erupted permanent dentition -No history of previous orthodontic treatment -No restorations -No congenital defects or deformed teeth -No obvious interproximal or occlusal wear of teeth www.indiandentalacademy.com
Materials & Methods www.indiandentalacademy.com
15 study models, near to ideal occlusion were collected from the P.M.N.M. Dental College & Hospital, Bagalkot. Another 33 study models of different malocclusion prior to treatment were collected from the Department of Orthodontics and Dentofacial Orthopedics.
FEMALE MEAN AGE
MALE MEAN AGE
â€˘The 15 study models were measured at the largest mesiodistal dimension using a digital caliper accurate to 0.01 mm. The individual tooth diameters were added to derive the anterior (distal of canine to distal of canine) , posterior (mesial of first premolar to distal of first molar on each side) and overall ratios (mesial of first molar to mesial of first molar ).
to define the following ratios: â€˘The segments were usedwww.indiandentalacademy.com
Measurement with Digital
Posterior ratio: posterior mandibular arch segment divided by the posterior maxillary arch segment.
Posterior ratio = sum of M-D of mandibular posteriors. X 100 sum of M-D widths of maxillary posteriors
Overall ratio: overall mandibular arch segment divided by over all maxillary arch segment.
sum of M-D widths of total mandibular tooth material X 100
Results And Discussion
The results of the present study has showed statistically significant difference between the overall and anterior ratios. In present study, we found that the posterior teeth were showing variation in the mesiodistal width and they were affecting the Boltonâ€™s ratio. These findings were similar to SAATCI YU KAY (1997). www.indiandentalacademy.com
the normal casts, the calculated anterior ratio measured
was found to be 78.32% and the calculated overall ratio was found to be 92.19%.
•The difference in ratios of the calculated values and the those average ratios given by Bolton’s (anterior ratio of 77.2% and overall
Discussion: According to Bolton (1958) the anterior and overall ratio play an important role in orthodontic diagnosis and they should match each other to attain ideal occlusion, but in several of our cases we found mismatch between overall and anterior decided to determine separately the anterior and ratio,so it wasratios. posterior www.indiandentalacademy.com
â€˘It is a well-known fact that there is a large variation in the size of front teeth. The size of the upper central incisors particularly may differ within the population. (Heusdens, Dermat, Verbeeck 2000 AJO) www.indiandentalacademy.com
But some times the premolars also show some amount of variations in the size and that is not considered in the Bolton analysis which may affect the Bolton ratio. Saatci and Yukay (1997), found that extraction of four first premolars was creating the largest tooth size discrepancy and the differences calculated for all extraction therapies were not significant from each other.
92.55% 78.72% www.indiandentalacademy.com 19.3Y/M 92.55% 77.08%
S.NO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
NAME REKHA JEKALI CHAYA HALTHI SANJAOUTHA RABIA UPPIN PARVIN.F RUMA SAMREEN ROHINI PATEL SHABANA MESTHRI YELLAMMA PATEL SAHANA KALLAR MADHURI.V ASHWINI.J GEETA BEHAL NIRMALA KALAL TAHSEN MUTAVVA JYOTHI HALHATTI SHAMBAVI VANI GIRIJA GAURI SAVITHA SINGAREDDY SHILPA SUCHITRA TAYYAKKA PATEL JYOTHI VASIM NALBAND SANTOSH GOWDAR VIKAS SHANKER PATEL RAMCHANDER VINOD SHIVALINGESHWAR MANJUNATH.P
AGE/SEX OVERALL RATIO ANTERIOR RATIO POSTERIOR RATIO 19Y/F 90.80% 83.30% 97.77% 20Y/F 93.50% 80.04% 106% 16Y/F 92.20% 82.00% 102.40% 19.4Y/F 87.60% 75.00% 95.90% 20.3Y/F 90.30% 76.00% 107% 16.1Y/F 90.50% 79.00% 99% 16.5Y/F 94.80% 79% 105.80% 21.6Y/F 91.50% 80.40% 102.40% 18.2Y/F 96.30% 82.50% 109.30% 20.5Y/F 92.30% 81.80% 97.80% 16.4Y/F 95.30% 80.40% 111% 15.6Y/F 91.30% 76.00% 106.30% 22Y/F 92.15% 84.60% 94.07% 21.6Y/F 83.50% 74.50% 98.00% 17.2Y/F 90.90% 81.50% 100% 15.3Y/F 91.10% 82.00% 100.00% 15.6Y/F 95.50% 88.80% 100.00% 19.3Y/F 95.00% 82.70% 107.10% 18.8Y/F 96.70% 100.00% 98% 20.6Y/F 91.80% 79.60% 104.08% 22Y/F 98.80% 85.70% 111% 20.4Y/F 90.60% 84.00% 98.03% 19.2Y/F 92.60% 77.00% 104.80% 18.6Y/F 87.30% 77.00% 98.14% 17.3Y/F 90.20% 75.10% 106% 17.6Y/M 90.40% 80.40% 100.00% 15.8Y/M 94.70% 87.20% 104% 16.3Y/M 94.30% 84.00% 104.40% 15.7Y/M 92.30% 80.00% 106.30% 20.2Y/M 89.70% 78.70% 100.00% 20.5Y/M 93.80% 78.40% 106% www.indiandentalacademy.com 21.8Y/M 93.13% 88.40% 98% 18.3Y/M 86.20% 79.10% 92.59%
TABLE .1 : STATISTICAL COMPARISION OF BOLTON STUDY VERSUS PRESENT STUDY:OVERALL RATIO
STANDARD DEVIATION 100 90
87.5 - 94.8
88.78 - 95.5
80 70 SAMPLE SIZE
TABLE .2 : STATISTICAL COMPARISION OF BOLTON STUDY VERSUS PRESENT STUDY:ANTERIOR RATIO BOLTON
74.5 - 80.4
70.8 - 86.0
STANDARD 4 DEVIATION
60 55 50
30 20 10
15 5 .6 1
0 www.indiandentalacademy.com BOLTON PRESENT
TABLE 3 : STATISTICAL ANALYSIS OF POSTERIOR RATIO PRESENT STUDY
94.1 - 113.4
STANDARD 4 DEVIATION
TABLE 4 : STATISTICAL ANALYSIS OF MALOCCLUSION CASES OVERALL RATIO
83.5 - 98.8
74.5 - 100
95.9 - 111.11
SAMPLE SIZE MEAN RANGE STANDARD DEVIATION 120 100
0 OVERALL RATIO
www.indiandentalacademy.com POSTERIOR ANT.
1] The amount and location of tooth size discrepancy in the
analysis of study casts in the orthodontic diagnosis would be more precise an accurate provided the anterior, posterior and overall ratios are calculated separately rather than calculating only anterior and overall ratios.
2] The calculated posterior ratios from the sample of 15 study casts with nea to ideal occlusion was found to be 104.3 %
3] There was no statistically significant difference found in the calculated www.indiandentalacademy.com
anterior and overall ratios in the present study and
â€˘The traditional anterior and overall ratios as prescribed by Bolton will give us an idea regarding whether the mandibular anteriors are in excess or deficient in relation to maxillary anteriors and whether the mandibular total tooth material is in excess or deficient in relation to total maxillary tooth material along with the exact amount of excess
They also gives an idea regarding the relation of
maxillary and mandibular posteriors to each other but not the amount of discrepancy.
The calculated mean value of posterior ratio can help us at arriving
â€˘Thus, it helps us to evaluate specifically which segment, anterior or posterior, is at fault so that achieving a correct end result incorporating all the six keys of occlusion as prescribed by Andrews may be possible.
â€˘This study suggests that it may be easier to diagnose and plan Maxillary v/s Mandibular tooth size discrepancy, if anterior and posterior ratios computed separately. www.indiandentalacademy.com
ACKNOWLEDGEMENT Dr. Sumant Goel Prof. & H.O.D.
Dr. Ravi Kallur Prof.
Dr. Radha Krishna www.indiandentalacademy.com
THANK YOU www.indiandentalacademy.com
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