CLASSIFICATION OF SKELETAL AND DENTAL MALOCCLUSION : REVISITED
Figure 1 . Skeletal classification
( skeletal III type 3 ), which gives detailed explanation aiding in diagnosis and treatment planning . ( Fig . 1 )
4.2 . Occlusal Classification : revisited The BSI and Katz ’ s classification deal with the partial description of the malocclusion . The British system of classification related to the anterior teeth where it needs further elaboration while Katz ’ s system focuses on the premolar occlusion and ignore the canines and molar classification . Snyder and Jerrold ( 2007 ), have concluded that a modification of Angle ’ s system that is more descriptive is needed , after they have sent an e-mail survey to the department chair or the program director of every orthodontic program in the United States , Canada , and Puerto Rico ( n = 80 ). The survey included photos of models placed into ¼ cusp , ½ cusp , and ¾ cusp distal occlusions , and the participants were asked to classify them by selecting from a list of terms or writing one of their own . They were also asked whether they thought that the Angle molar classification was adequate for communication and diagnosis . Fourty surveys were completed and returned . The results showed a variety of terminology being taught , and most educators do not use Angle ’ s classification as he defined it . About half of the respondents were dissatisfied with the Angle molar classification system 17 . In 2002 Siegel conducted 57 surveys which were mailed to department chairs in the United States , asking them to identify the definition to which their orthodontic residency program subscribes ; 34 questionnaires were returned .
Twenty-two responses supported the notion that subdivision refers to the Class II side , 8 responses said that it refers to the Class I side , 3 responses supported neither view , and 1 response indicated that in the program not everyone could agree on the meaning of subdivision . Although the prevailing belief appears to be that subdivision indicates the side with a molar malocclusion , the orthodontic community does not have a consistent standard , and it is time to resolve this controversy 18 . Due to the low reliability of the Angle method , a reconsideration is needed to develop the older classification . The reconsideration is done in the antero-posterior and on both sides , where molar classification is more elaborated . In this revision class IV , V and VI are generated which helped in treatment planning and suggesting treatment protocol . Skeletal Class III malocclusion was strongly differentiated from the other sagittal classes , specifically in the mandible , as calculated through Björk and Jarabak analysis 19 . A review article emphasizes the need to identify genetic and environmental factors that cause or contribute risk to skeletal malocclusion and the possible association with other medical conditions to improve assessment , prognosis and therapeutic approaches 20 . Accurate and detailed classification is always needed to drive an accurate diagnosis and treatment plan . The author followed the BSI incisor classification with modifications for class II and III , accepts canine classification and modifies molar classification , which are further elaborated for the ease of diagnosis and accuracy of treatment planning in orthodontics . 4.3 . Incisor ’ s Classification ( Fig . 2 ) Class I : When the mandibular incisor edges lie or are below the cingulum plateau of the maxillary incisor ( BSI , 1983 ), the overjet is 2-4 mm . Class II : When the mandibular incisors edges lie posterior to the cingulum plateau of the maxillary incisors ( BSI , 1983 ). It could be :
• Class II / 1 : Proclined maxillary incisors with overjet more than 4 mm .
• Class II / 2a : Retroclined maxillary centrals and proclined laterals , or both central and lateral incisors are retroclined with normal or reduced overjet .
• Class II / 2b : Retroclined maxillary centrals and proclined laterals , or both central and lateral incisors are retroclined but with increased overjet . Class III : When the mandibular incisors edges lie anterior to the cingulum plateau of the maxillary incisors ( BSI , 1983 ).
• Class III type 1 : Positive overjet but less than 2 mm .
• Class III type 2 : Edge to edge incisors relationship .
• Class III type 3a : Negative overjet .
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