CLASSIFICATION OF SKELETAL AND DENTAL MALOCCLUSION : REVISITED
the primary teeth , in addition did not classify the skeletal relationship and did not predict the etiological factors , so revisiting was always needed . In 1915 Deway ’ s modified Angle ’ s Class I and III malocclusion by segregating malposition of anterior and posterior segments , CL I : type 1 ( Crowding of Max anterior teeth ); type 2 ( Proclined Max incisors ); type 3 ( Max incisors are in crossbite ); type 4 ( Posterior cross-bite ); type 5 ( Mesial drift of molars ). CL II ( no modifications ). CL III : type 1 : ( Edge to edge bite ), type 2 : ( Crowded Mandibular incisors and lingual to Max incisors ); type 3 : ( Underdeveloped crowded Maxillary arch and a well developed Mandibular arch ) 4 . Lischer in 1933 further modified Angle ’ s classification by giving substitute names ; CL I ( Neutrocclusion ); CL II ( Distocclusion ); CL III ( Mesiocclusion ). He also proposed terms to designate individual tooth malposition , Mesio-version ( Mesial to normal position ); Disto-version ( Distal to normal position ); Linguo-version ( Crossbite ); Labio-version ( Increased OJ ); Infra-version ( Submerged tooth ); Supra-version ( Super-erupted ); Axio-version ( Tipped tooth ); Torsiversion ( Rotated tooth ); Trans-version ( Transposed tooth ) 5 .
3 . Results Ackerman and Proffit ( 1969 ) introduced a very comprehensive system of classification using the Venn diagram . The classification considered five characteristics and their inter-relationships were assessed , namely : alignment , profile , transverse , class and overbite 6 . Angle ’ s classification still seems to be the most popular tool for classification of malocclusion , despite its well-known disadvantages 7 . Hans et al ., ( 1994 ), noted the inadequacy of Angle ’ s classification when they were unable to classify approximately 7 % of a large sample ( n = 4309 ) of models in the Broadbent-Bolton study 8 . Another study conducted by Baumrind et al ., ( 1996 ) on whether to extract in orthodontic treatment , found that 28-33 % disagreement among the 5 participating orthodontist 9 . Katz ( 1992a ) showed an inter-examiner disagreement of 49 % among 270 orthodontists using Angle ’ s classification 10 . The percentage agreement of Katz ’ s technique proved superior to that of the classical Angle ’ s classification 11 , 12 . Rinchuse found Angle ’ s classification to be limited because it is a system of discrete classes as compared to continuous transition of maxillomandibular dental arches in the sagittal plane 13 . The British Standard Institute ( BSI ) classified dental malocclusion in 1983 according to the maxillary and mandibular incisors relationship . Class I : When the mandibular incisor edges lie or are below the cingulum plateau of the maxillary incisors . Class II : When the mandibular incisor edges lie posterior to the cingulum plateau of the maxillary incisors , the maxillary incisors could be proclined where it is classified as Class II / 1 , or retroclined maxillary centrals and proclined laterals , or both central and lateral incisors are retroclined where it is grouped under Class II / 2 . Class III : where the mandibular incisor edges lie anterior to the cingulum plateau of the maxillary central incisors 14 . The BSI classification was more accurate in grouping the malocclusion 15 . The British method of overjet and overbite assessment 15 and the quantitative technique proposed by Katz ( 1992b ) 16 developed over the years , proved to be more amenable to reproduction than Angle ’ s classification 11 , 15 . In the Du et al . study ( 1998 ) in their study where four orthodontic faculty members at one dental school classified 25 dental casts according to the classification systems of Angle , Katz , and the British Incisor Classification 11 . The dental casts were selected from a pool of 350 pretreatment graduate orthodontic cases and were those deemed the most atypical . The results demonstrated that Katz ’ s classification was more reliable than both the Angle and the British one . Angle ’ s classification was the least reliable of the three methods .
4 . Discusion 4.1 . Skeletal classification : revisited In the author ’ s view orthodontic skeletal classification could be grouped into class I ( straight ), class II ( convex ) and class III ( concave ). Salzmann ’ s classification did not specify that the problem is due to maxillary protrusion , mandibular retrusion or a combination of both . The same is true for the concave profile , his method did not specify that the problem is due to maxillary retrusion , mandibular protrusion or a combination of both . The author agrees with all scholars that skeletal class I has a straight profile ( Fig . 1 ), which explains homogeneous relationship between the maxilla and mandible , or in another terms they grow in unison . In cases of Skeletal I the problem is dental malrelationships . It is present in two planes , the vertical and the transverse planes where the anteroposterior plane is normal or within average . There is always a question which arises in cases where it is straight to mild convexity or mild concavity . The author ’ s view is to enlarge the description of skeletal I so as to include the mild convexity and mild concavity as far as it is confirmed by the ANB angle . The range of skeletal I would be straight to mild convexity or mild concavity . Salzmann ’ s Skeletal II ( convex profile ) did not indicate either whether it is due to protruded maxilla or retruded mandible or a combination of both . In the present study , Skeletal II could be of three types ; type 1 ( retruded mandible ), type 2 ( protruded maxilla ) and type 3 ( combination of both ). ( Fig . 1 ) The same applies for Class III ( concave profile ), again Salzmann did not specify either whether it is due to maxillary retrusion or mandibular protrusion . According to my explanation it could be due to maxillary retrusion ( Skeletal III type 1 ), or mandibular protrusion ( Skeletal II type 2 ), or a combination of both
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