Incomplete fractures in intact bilateral maxillary first molars: A case report

Koichi Ito, DDS. MSD*/Koichi Nanba. DDS**/Toshikazu Akashi, DDS DDSc***/ Seidai Murai. DDS. DDSc****

A case of incomplete fractures occurring biiaterally in intact ma.xillaiy fust molars i.s described. The etiology, diagnosis, and treatment of incomplete fractures an discussed. The clinical results in tills case showed that early diagnosis and treatment can prevent further extension of the crack into the and subsequent complete tooth fracture. (Quintessence Int 1998 ;29:243-248]

Key words: cracked-tooth syndrome, incomplete tooth fraciure. intaci molar

omplete and incomplete fractures (cracked-tootli 30 to 59 years,'' tbose who are middle aged or oldei,' or Csyndrome! within the coronal and root structures of those aged 50 years or older,** Studies of incomplete teeth are fairly cotnmon dental findings,' However, ex- fractures bave revealed that tbe mandibular second mo- cept in cases of a;:cidentai trauma, the etiology of such lar fractures most often.•'•^ and investigations of com- fracture.'; is not well recognized, pleie and incomplete fractures have sbown that tbe OccUisal trauma is defined as an injury to the attach- mandibular first molar is affected most frequently.^'" ment apparatus as a resuh of excessive occlusal force.- We recently encountered a patient with incomplete including injury lo any part of the masticatory system fractures of intact maxillary first molars bilaterally, a resulting from abnormal occlusal contact relations and/ rare condition. The present case report describes the or abnotroal function, Occlusal irauma may be manifest- treatment for these incomplete tooth fractures and tbe ed in the periodontium, hard structures of the teeth, pulp, findings at 2-year follow-up. temporomandibular joints, soft tissues of the mouth, and neuromuscular system. In some cases, tbe crowns and/or Case report roots of intact teeth are fractured during episodes of ,' Hiatf* bas stated ibat splitting or fracturing of A 55-year-old Japanese man visited the Department of the teeth is a sign of bruxism. of Nibon University Dental Hospital Clinical studies of fractured teetb bave reveaied that complaining of vague discomfort in the maxillary right more fractures occur in teeth with large restorations molar region. His medical history revealed no docu- than in tbose witb small or no restorations,•'^'^ Tbere is no mented systemic problems. He worked as a professor at consistent age group of patients most likely to have Nihon University School of and was under fractured teetb. Most fractures occur in individuals aged considetable stress, smoking 20 to 30 cigarettes daily and occasionally drinking alcoholic beverages. His fam- ily history was noncontributory. He had undergone orthodontic therapy for Class i mal- ^Associate Proressor, Department of Periodontology. Nilion Univer- occlusion between tbe ages of 26 and 27 years, surgery sity, School or Dentistry, Tokyo. Japan, for a mucous cyst in the right maxillar>' sinus at the age ""Graduate Student, Department of Periodontology, Nihon University, Graduate School of Dentistry, Tokyo, Japan. of 50. and occasional tooth cleaning each year. He had no '"Assistant Professor, Department of Endodontics, Nihon University. histor>' of allergic reactions to anesthetics or drugs. Apart School of Dentistry. Tokyo, Japan, from slight obesity, there were no apparent abnormalities '»'•Professor and Chairman, Department of Peri odontology, Nihon or patboses associated with tbe face or neck, except for University, School of Dentistry, Tokyo. Japan, slight hypertrophy of the masseter muscles (Fig 1), Reprint requesis: Dr Koichi Ito, Department of Periodontology, Nihon The patient complained of pain in the maxillary right Uniiersity. School of Dentistry. 1-8-13, Kanda-Sunigadai, Chiyoda-ku, Tokyo 101, Japan, Fan: 81-3-3219-8349, posterior teeth on occlusion. He had 28 natural intact

International 243 Ito et al

Fig 1 Slight bilateral hypertrophy of the Fig 2 No abnormal findings are present in ihe sinus, temporo- masseter muscles is evident. mandibuiar joints, alveolar bone, tooth structures, or periapical areas.

teeth with no restorations or large areas of caries. The margin (Fig 4). Because fracture of the tooth was not probing depths were 2 to 3 mm throughout the mouth. complete, and no bleeding from the pulp or pocketing Bleeding on probing was noted, and slight generalized (about 2 mm) was evident, the tooth was filled with gingival inñamtnation was evident. Tooth tnobility was light-cured resin composite for a Class II restoration (Fig within normal hmits. and there were no severe periodon- 5). Occlusal adjustment was performed to achieve cert- tal or endodontic prohlcms. Initially, recurrence of maxil- tric occlusion and a centric relation. Group-functiort lary and/or mucous cyst was suspected, but a occlusion during both right and left mandibular move- panoramic radiograph revealed no abnonnality (Fig 2). ments was noted. Percussion of the maxillary right first molar in differ- Because wear facets were noted on the tnaxillary and ent directions evoked pain. The patient was asked to mandibular canines, light-cured resin composite (GC) bite a wooden toothpick and complained of pain when was added to the incisai edge of the maxillarj' canine to the biting pressure was released. A hairiine fracture .secure canine guidance and relieve the lateral force on the was noted during examination with a fiberoptic light first molars (Figs 6 and 7). Because the long-term prog- (Saphon Oral Illuminator. Tokyo Shizaisha), The frac- nosis of this tooth was questionable, observation was con- ture in the tooth was confirmed by exploration with the sidered advisable. Six months later, a temporary cast- sharp point of a ftne explorer. The hairline fracture ex- rnetal ei own was prepared for the right first molar (Fig 8), tended over the mesial marginal ridge and to the mesial About six months after the emergency treatment, the surface of the tooth (Fig 3). Thermal tests .showed sensi- patient visited again, complaining of on the tivity to heat and cold. An electric pulp test evoked a left side. Almost identical examinations of the left poste- positive re.sponse. tior regions were performed, and an incomplete fracture An incomplete fracture of the intact maxillary right of the intact maxillary left first molar, like that of the first molar was diagnosed on the basis of the information right first molar, was diagnosed (Fig 9). Similar treat- gathered from these clinical exatninations. Under local ment was therefore performed (Figs 10 to 13). anesthesia, emergency treatment was performed to iden- The patient was reevaluated 6 months later, and this tify the location and extent of this fracture and its rela- revealed exacerbation of pulpal pain in the maxillary left tionship to both the pulp and clinical attachment level. tlrst molar. Fndodontic treatment was completed, and a The tooth was prepared from the mesial proximal sur- permanent cast-gold crown was made and cemented (Fig face to the occlusal surface by grinding with a tungsten 14). Pulpal and periodontal assessment of the maxillary carbide bur (No. 330, Shufu). This revealed that the hair- right first molar with the temporary ca.st-metal crown line fracture extended to the pulp and below the gingival revealed no problems.

244 Volume 29, Number 4, 1998 Fig 3 A tiairiine tracture (arrows) is evident m ttie inLact maxillary Fig 4 Ttie cavity preparation reveals a hairline fracture (arrows) (ight first molar. that is thought to extend into ttie pulp.

Fig 5 After the location and extent of the tracture were ideniified, Fig 6 A wear facet is present on ttie maxillary right canine. emargericy treatment was performed with an adhesive resin bonding system.

Fig 7 The wear lacet has been resloreO with light-cured resin Fig 6 A cast-metal crcwn has been fabricated anO cemented composite. with a temporary cement.

245 lio et al

Fig 9 A hairline fracture (arrows) is present in ihe intact maxillary Fig 10 The cavity preparation reveáis the location and extent of left first moiar (in aimost the same area as that shown in Fig 3). the fracture (arrows)

Fig 11 Emergency treaiment was performed with light-cured Fig 12 A wear facet is present on the left canine. resin composite.

Fig 13 Light-cured resin composiie has been built up on the Fig 14 After endodontic treatment, a finai cast-gold crown was wear facei of the ieft canine. made and cemented on the maxiiiary left first moiar.

246 Voiume-29, Number 4, Figs 15 and 16 Radiographs reveal no bone résorption or penapicai pathoses, except for slight caloulus deposits at the ce m en toe name I junction on some teeth

Reevaluatioti 2 years aftei tbe fmal treatment sbowed retains bis or her teeth, the greater the likelihood of that botb maxillary ñrst molars were well maintained acquiring factors that predispose them to fracture: main- and functioned witbout discomfort, except for slight ly worn cusps, steep cusp-fossa relationships, large sensitivity of the maxillary right first molar to cold intracoronal restorations, traumatic occiusai relation- water {Figs 15 and 16). ships, and bruxism. Eakle et al'^ investigated 191 patients with 206 com- Discussion plete or incomplete fractures of posterior teeth. The number of fractures in each arch was almost equal, 105 Tootb fractures are fairly cotnmon and tnandibuiar first and 101 fractures being found in the maxilla and or second molars are reported to be affected tnost fre- , respectively. The first molars were fractured quently.-'-''"' Tbe present patient had an interesting case more frequently than the second or third molars. The of incomplete fractures occurring bilaterally in intact mandibular first molar was the posterior tooth that frac- maxillary first molars. tured most frequently. The buccal and lingual cusps of Hiatt^ reported on iOO incotnpletely fractured teeth in maxillary molars fractured with almost equal frequency 64 patients and found that the cracks progressed to the ¡buccal: 50.0%; lmgual: 45.2%), whereas mesial-to-dis- pulp, leading to development of a periudontal pocket tal eracks occurred in only 4.8% of cases. Of the 206 along the fracture line. Seventy-fotir percent of the teeth fractured teeth, 19.9% had incomplete fractures and 18R with fractures had no restorations or Class I restorations. (91.3%) had amalgam restorations. Of the fracture.^ in Although it was speculated that most of the fractures restored teeth, 94% occurred when the isthmus widths resulted from the working of the occlusion, it wa.'; diffi- of the restorations were a third or more of the intercus- cult to evaluate a histoty of clenching, bruxism, balanc- pal distance. ing interference, psychologic stress, etc. The dental characteristics of our patient were in ac- Cameron' studied 102 posterior teeth with cracks and cord with those reported by Cameron.^-^ However, to fouud that 3Q9c of the pattents were aged 60 years or our knowledge, tbere have been no reports of bilateral older, 28% were aged 50 to 60 years, 22% were aged 40 incomplete fractures of similar degree, in almost the to 50 years, and only 20% were younger than 40 year'; same areas, in intact maxillary first molars, hke those in of age. A patient who had one cracked tootb was likely this patient. In this case, the hairline fractures extended to crack another, the wear being moderate in 81% of the over the me.'.ial marginal ridges and to the mesial sur- cracked teeth and severe in 13%; the other cracked teetb faces of both the intact maxillary first molars. showed no wear. Two thirds of the 102 cracked teetb Most patients with a fractured tooth complain of were tnaudibular molars (30 first molars and 38 second symptoms sueh as pain on chewing, toothache, and sen- molars) and only nine were maxillary first molars. sitivity to pressure, cold, beat, sweet foods, and/or tap- Cameron^ has also stated that teeth become brittle ping. This patient experienced pain on chewing with witb age and crack more easily. The longer a patient vague discomfort in both maxillary molars. Transverse

247 fractures can be visualized readily by radiograph, but treatment and bad a stable occlusal relationsbip, every longitudinal splits of tbe root are almost impossible to tooth receiving exactly the same pressure at exactly the see on radiographs,' Although the cracks in ihe maxil- same time wben tbe teeth were brought together. lary first molars of tbis patient extended in a me,siodistal Therefore, we .speculate tbat the etiology of the tooth direction, tbeir depths atid lengths appeared to differ. cracks in thi,s case was severe stress due to the steep Because the niaxillary right first molar was cracked cusp-fossa relationship, which acted as a splitting superficially, [his tootb was first treated provisionally force. Furthermore, the moderate wear facets on all of witb an adhesive resin bonding system, and later a cast- the patient's canines suggested occlusal interference tnetal crown was cemented to it. However, the crack in during eccentric excursion, the resulting lateral force the maxillary left first tuolar was already deep, and end- also acting as a splitting force. odontic treatment bad to be perfonned, Tbis tooth was Further long-term follow-up is required to justify the also restored and covered witb a complete cast crown. present treatment for this type of tootb fracture. These early treatments appeared adequate for prevent- ing the cracks from affecting the periodontium and pro- Acknowledgments ducing deep pockets. Tbe prognosis of tbe treated teeth is still uncertain, and further clinical and radiographie The authors wish to thank Dr David B. Douglas for his assistance in examinations will be needed. manuscript preparation. When a patient complains of pain localized to one tootb. especially if tbis pain is triggered by mecbanical References activity, the po.ssibility tbat tbe tootb is cracked sbould 1, Hall WB. Cracked tooth syndrome. In: Hall WB. Roberts WE, be investigated.' The facial appearance of the patient in LaBarre EE (eds). Decision making in dental treatment planning. tbe present study .suggested slight hypertrophy of the St Louis: Mosby, 1994:12-15, masseter muscle.s (see Fig I]. Patients with bruxism 2, Glossary Committee. Glossary of Periodontic Terms, Chicago: often develop unilateral or bilateral bypertropby of the American Academy of Periodontology, 1985:20, masticatory muscles, especially the masseter muscles.-' 3, RamQord S, Ash MM, Occlusion, ed 3. Philadelphia: Saunders, The patient was therefore suspected to be a bruxer on 1983:178,188-189,320-321,330, 4, Hiatt WH. Incomplete crown-root fracturei in pul pal-periodontal the basis of this feature. disease, J Periodontol 1973:44:369-379. Although extensive is usually the result of 5, Cameron CE. The cracked tooth .iyndrome: Additional ñndings, J bruxism, analysis of study casts revealed sligbt-to-mod- Am Dent Assoc l976;93:97l-975. erate wear facets throughout this patient's mouth, and 6, Snydcr DE. The cratked-Looth syndrome and fractured posterior tbis appears to be a common finding in patient.s of a cusp. Orul Surg Or^l Med OrLÜ Pathol 1976:41:698-704. similar age. Extremely steep cusp-fossa relationships 7, Tiilim ST, Gohli KS, Management of coronal fractures of perma- were noted in botb tbe maxillary and mandibular molar nent posterior teelh, J Prosthet Dent 1974;31:172-178. 8, Cameron CE, Cracked-tooth syndrome. J Am Dent Assoc 1964; regions. The angle of inclination of each cusp on both 68:405-411, the maxillary and mandibular first molars was 5,3 de- 9, Fciguson NC. Fractured cusps, J Am Acad Gold Foil Oper 1972; grees, steeper tban tbe average value for Japanese adult 15|l):19-24. patients," I [) Eakle WS, Maxwell EH, Braly BV, Fractures of posterior teeth in Abnormal clencbing (centric bruxism) refers mainly adults, J Am Dent Assoc I986;l 12:215-218, to habituai clenching of the jaw muscles without the 11, Hayakawa T, Studies on the occlusal facets of posterior teeth. For presence of any obvious psycbologic or pbysical emer- rccon.struction of" the functional occlusal pattern, J Jpn Frosthodont Soc 1971;I5:35O-38O (in Japanese), gency situation. The patient is almost alway.s unaware of this babit,-' This patient had undergone ortbodontic

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