AJOHS 2016 V1 (1) 4 African Journal of Oral Health Sciences

Nyaga J. M1, Maina S.W2, Gathece L.W2, Okoth J2 ROOT CURVATURE IN THE MAXILLARY FIRST PERMANENT MOLARS IN A 1Department of conservative and Restorative dentistry University of Nairobi KENYAN POPULATION 2Department Periodontology, Community and Preventive Den- tistry, University of Nairobi

Abstract

Objective; To determine the root curvature in the maxillary first permanent molars Methodology; A total of 187 maxillary molars were collected from male and female patients aged between10 and 40 years. The teeth were orientated in their anatomical positions on a calibrated graph paper and the root curvature determined with reference to the long axis of root from the bifurcation. Results; Majority of the mesiobuccally roots (63.6%) were curved and of the curved, 95% curved distally. In the distobuccally root, 49.7% of the roots were curved and majority (77.4%) curved mesial. Majority of the palatal roots were straight (65.3%). Of the curved palatal roots, 92.5% curved in a buccal direction. The gen- der variations in root curvature in maxillary first permanent molars was not statistically significant. Conclusion; Palatal root in maxillary first permanent molars had the lowest frequency of curved roots. Key words; roots, curvature, maxillary, molars

Introduction straight ones.10 Angled views are Materials and Methods necessary to determine their The knowledge of the complexity This was an in vitro-cross sec- presence, direction, and severity. in the root canals and the direc- tional descriptive study which A curvature may be a gradual tion of curvature help in the un- was conducted at the University curve of the entire canal or a derstanding of the principles and of Nairobi, School of Dental Sci- sharp curvature near the apex. problems of shaping, cleaning ences. One hundred and eighty Double S- shaped canal curva- and post placement in the canal seven maxillary first permanent tures have also been reported.4, 11 system. In addition, it facilitates molars extracted from Kenyans A separated instrument is one of performance of microsurgical of African descent aged between the most troublesome incidents procedures successfully.1 10 and 40 years were collected in in endodontic therapy.10 Through four oral health care facilities Thus evaluation of the root cur- recall radiographic evaluation, within Nairobi. The teeth were vature is a crucial step during the frequency of remnant sepa- grouped into two at the collec- chemo mechanical preparation rated instruments is reported to tion point based on gender. The and the ost space preparation. range between 2% and 6%.10 extracted teeth were washed in Curved roots have curved canals Most of the instrument separa- tap water immediately after ex- and based on the severity of cur- tion is reported to occur in the traction. Then immersed in vature, may have negative im- molars and the most canals in- 3.85%m/v sodium hypochlorite pact on instrumentation during volved are the mesial canals of solution (Reckitt Benckiser E.A. shaping and post space prepara- mandibular molars followed by Nairobi, Kenya) for a minimum tion. The root curvature is re- the buccal canals of maxillary of thirty minutes to remove ad- ported to influence the outcome molars.32 Investigators have re- herent soft tissue and for disin- following canal prepation.2, ported a wide variations in first fection. Subsequent storage was 3 permanent root curva- done in 10% formalin solution tures. Researchers have fre- Nearly all roots are reported to till the day of analysis. During the quently applied the radiographic be curved, particularly in a mesi- analysis, the teeth were orientat- technique to determine the root odistal or buccolingual direc- ed in their anatomical positions curvatures. However convention- tion.4, 5, 6, 7, 8, 9 These curvatures on a calibrated graph paper al radiographs may only demon- may pose a problem during the (Kartasi Graph Book, Nairobi strate the main features and are shaping and cleaning procedures Kenya) and the root curvature unlikely to show the complexities because they are not evident on a determined with reference to the of root anatomy.12, 13 In addition, standard facial radiograph. The long axis of root from the bifur- radiographs are two dimensional number of cycles necessary to cation. By visual examination of and are open to a wide range of induce cyclic fatigue fracture in the root against the grid, it was interpretation according to rotary instruments is lower in determined whether the root is Omear et al.2004.14 curved canals compared to straight, curved towards mesial,

12 A Publication of the School of Dental Sciences AJOHS 2016 V1 (1) 4 African Journal of Oral Health Sciences

buccal, lingual, palatal or curved variations in the straight, mesially in multiple directions (see Figure curved and distally curved roots 7). was not statistically significant [χ2 =1.14, d.f. 2 and P=0.57(>0.05)]. The direction of the root curva- ture was determined by the posi- In the palatal root, males had a tion of the root apex from the higher frequency of straight roots long axis of the root. 61(69.3%) compared to females 59(59.6%). Of the curved roots, Results root curvature in the buccal di- Table 1 shows the frequency of rection was higher in males 25 curved and straight roots in max- (92.6%) compared to females 37 illary first molars. Generally, the (92.5%). The observed differ- maxillary first molar roots were ences between the genders in frequently curved 283 (50.5%). straight versus buccally curved The mesiobuccal root was the roots was not statistically signifi- most frequently curved 65.8% Figure 7: Diagramatic represen- cant [χ2 =1.81, d.f. 1 and P=0.18 while the palatal root was the tation of determination of root (>0.05)]. least curved 67 (35.8%). Similar- curvature Discussion ly, the palatal root had highest frequency of straight roots 120 Table 1: The frequency of straight and curved roots in the maxillary (64.2%) compared to distobuccal 94 (50.3%) and mesiobuccal first molars roots 64 (34.2%). The observed Root Root curvature Test done variation among the straight ver- sus curved roots in the maxillary Straight Curved first molar was statistically signif- No % No % icant (χ2 =34.39, d.f. 2, P<0.05). Table 2 shows the direction of Mesiobuccal root 64 34.2 123 65.8 root curvature in maxillary first molars. Majority of mesiobuccal χ2 =34.39, d.f roots 118 (95%) were curved Distobuccal root 94 50.3 93 49.7 2, p<0.05 distally, 2 (2%) were mesially curved, 2 (2%) were S shaped Palatal root 120 50.3 93 49.7 and 1 (1%) curved palatally. Of the distobuccal roots, 72 (77.4%) were curved mesially, 16(17.2%) curved distally, 1 (1%) curved Table 2: Directions of root curvature in maxillary first molars lingually, 1 (1%) curved buccally, and 3 (3.2%) were S shaped. Of the curved palatal roots, 62 Root Direction of root curvature (frequency in percentage) (92.5%), 4 (6%) and 1(1.5%) curved buccally, palatally and S mesial distal palatal buccal others shaped respectively. Palatal root MB (n=123) 2 95 1 0 2 curvature in a distal or mesial direction was not observed. Fe- DB (n=93) 77.4 17.2 1 1 3.4 males had lower frequency of straight roots 29(29.6%) com- P (n=67) 0 0 6 92.5 1.5 pared to males 49(58.3%) in the mesiobuccal root. Of the curved Total (n=283) 26.1 47.4 2.1 22.3 2.1 mesiobuccal roots, 49(92.5%) in males and 69(98.6%) in females curved distally. Mesiobuccal root Majority of the roots in maxillary distobuccal root, straight roots curvature in mesial and palatal first permanent molars were were more frequent in males 48 direction was observed among curved. The palatal, mesiobuccal (55.8%) than in females 46 males. and distobuccal roots frequently (47.9%). Of the curved distobuc- curved buccally, distally and me- However, the observed gender cal roots, 31(77.5%) and 41 sially respectively. Previous stud- variation in the straight versus (77.4%) were curved mesially ies by Dienya et al. 20088 and Pec- the distally curved roots was not while 7(17.5%) and 9(7%) were ora et al. 19917 reported frequen- statistically significant [χ2 =2.89, curved distally among males and cies of 90.0% and 54.6% for buc- d.f 1 and P=0.09(>0.05)]. In the females respectively. The gender

13 AJOHS 2016 V1 (1) 4 African Journal of Oral Health Sciences

cally curved palatal root, 95.2% of Dental Sciences, University of canal morphology of 1st per- and 86.5% for distally curved Nairobi where the study was manent molars amongst Ken- mesiobuccal roots, 73.8% and conducted. The study was ap- yan adults. Research report 32.6% for mesially curved dis- proved by the Ethics and re- submitted for the partial ful- tobuccal root respectively. Bone search Committee of the Kenyat- fillment of degree of masters et al. 19869 in a sample of 100 ta National Hospital and Univer- of Dental Science first molars reported that 90% of sity of Nairobi (P219.8.2008). (endodontics) University of palatal roots were curved and of Malaya Kuala Lumpur 2008. References the curved roots, 85% curved 9. Bone J, Moule AJ. The nature buccally among the Australians. 1. Vertucci FJ. mor- of curvature of palatal canals The variations in frequencies phology and its relationship in maxillary molar teeth. In- between this and previous stud- to enodontic procedures. En- ternational Endodontic Jour- ies may be attributed to the vari- dodontic Topics 2005; 10: 3- nal1986; 19: 178-186. ations in study samples and 29. methodology used. Dienya et al. 10. Mian K, Iqbal, Meetu R, Kohli, 2. Peters OA, Laib A, Gouring 20088 used CBCT to determine Jessica S, Kim. A Retrospec- TN, Barbakow F. Changes in root curvature which differs tive Clinical Study of Inci- root canal geometry after from this study’s graphic method dence of Root Canal Instru- preparation assessed by high in precision. Bone et al. 19869 ment Separation in an Endo- resolution Computed tomog- used a radiographic method dontics Graduate Program: A raphy. Journal of Endodontic which differs from graphic meth- PennEndo Database Study. 2001; 27: 1-6. od in this study which did not Journal of Endodontics 2006; classify the degree of root curva- 3. Peter OA, Peters CI, Schonen- 32:1048 –1052. ture. In addition, there was racial berger k, Barbakaw F. ProTa- 11. Berkovitz BK, Holland GR, variation in the samples used. per rotary root canal prepara- Moxham BJ. Oral Anatomy, Pecora et al.19917 sample was tion: assessment of torque Histology and Embryology. from Caucasian population com- forces in relation to canal Mosby, Elsevier Science Lim- pared to African population in anatomy, International Endo- ited Third Edition 2000 Page this study. dontic Journal 2003: 36; 93- 13-33. 99. Endodontic treatment in curved 12. Omer OE, Al Shalabi RM, Jen- roots has been associated with 4. Frank J, Vertucci, James E, nings M, Glennon MJ, Claffey disastrous consequences such as Haddix, Leandro R, Britto. NM. A comparison between loss of working length, apical Tooth Morphology and Access clearing and radiographic transportation, and creation of Cavity Preparation in Path- techniques in the study of the ledges, perforations and instru- ways of the , Ninth Edi- root-canal anatomy of maxil- ments separation. tion Elsevier Mosby 2006; lary first and second molars. 148 -232. Conclusions and Recommen- International Endodontic dations 5. Enrique P, Richard Z, Peter Y. Journal 2004; 37: 291-296. Root curvature localization as Palatal root in maxillary first mo- 13. Insoo k, Ki-suk P, seung-pyo indicators of post length in lars had the lowest frequency of L. Quantitative Evaluation of various tooth groups. Dental curved roots. In the curved pala- the Accuracy of Micro- Traumatology 2006; 2 (2): 58 tal roots, 92.5% curved buccal. Computed Tomography in -61. Thus the palatal root of maxillary Tooth Measurement. Clinical first permanent molars are the 6. Sharma R, Pecora JD, Lumley anatomy 2007; 20: 27-34. most suitable for post placement. PJ, Walmsley AD. The external 14. DE Moor RJ, Deroose CA, Cal- Further research is needed to and internal anatomy of hu- berson FL. The radix entomo- determine and classify the sever- man teeth laris in mandibular first mo- ity of root curvatures in first per- with two roots. Endodontic lars: an endodontic challenge. manent molars Dental Traumatology 1998; International Endodontic 14: 88-92. Acknowledgements Journal 2004; 37: 789–799. 7. Pecora JD, Woelfel JB, Sousa To the dentists in the various Corresponding Author N. Morphologic study of the dental clinics in Nairobi, who James Nyaga maxillary molars part 1: Ex- facilitated the collection of the Department of conservative ternal Anatomy. Brazillian extracted teeth for this study. and Restorative dentistry Dental Journal 1991; 2(1):45- They are also grateful to the de- University of Nairobi 50. partments of Conservative and Email: Prosthetic Dentistry and the Oral 8. Dienya JM, Yeti R, Norliza I. [email protected] and Maxillofacial Surgery, School Determination of root and

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