Risk factors for the appearance of cracks and fractures of teeth according to a survey of dentists

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BACKGROUND

Cracked and fractured teeth are frequently encountered in clinical dental practice [1, 2]. In the majority cases, such teeth are non-restorable and require extraction. Exceptions include teeth with fractures confined to the coronal third of the root, where restoration using post-retained cores may be considered feasible [3–6].

The emphasis on preventive care in contemporary dentistry has heightened interest in identifying and predicting complications of dental hard tissues, including cracked and fractured teeth. However, comprehensive and detailed investigations into these conditions remain limited.

AIM: To assess the detectability of risk factors for cracked and fractured teeth based on a survey of practicing dentists.

METHODS

A total of 52 dentists representing various dental specialties were surveyed using a structured, custom-designed questionnaire. The participants had a mean clinical experience of 12.4 ± 3.4 years. The questionnaire consisted of 24 items grouped into 7 sections with multiple-choice formats (Table 1). It addressed the prevalence and characteristics of cracked and fractured teeth, biomechanical loading conditions, and time intervals following restoration and prosthetic treatment. Among the respondents were 19 general dentists, 18 oral surgeons, and 15 prosthodontists.

 

Table 1. Key findings of the dentist survey on tooth cracks and fractures

Question	Answer
	No.	%
1. Indicate the number of teeth with fractures and the number of teeth with cracks observed in your clinical practice	526 803	39,6 60,4
2. What percentage of treated and extracted teeth were fractured or cracked?	1331 1326	12,1 10,2
3. How frequently did the following tooth characteristics and functional conditions occur among fractured or cracked teeth (%)?
Incisors Cuspids Bicuspids Molars	206 22 701 400	15,5 1,7 52,7 30,1
Maxilla Mandible	830 499	62,5 37,5
Crack or fracture site: crown root	544 785	40,9 59,1
Crack or fracture type: longitudinal transverse	906 423	68,2 31,8
Detected on: X-ray only CT only	78 129	5,9 9,7
Devitalized teeth	1166	87,7
Mobile teeth	71	5,3
Excessive occlusal load: unreplaced missing teeth bruxism	1052 388	79,2 29,2
Occlusal interference	169	12,7
Jawbone resorption > 1/3 root near cervical line	400	30,1
Periapical bone resorption	124	9,3
Cavity > 50% of the occlusal surface	1014	76,3
Presence of: composite restoration > 50% of the occlusal surface cast post-and-core metal post glass fiber post	655 291 280 137	49,3 21,9 21,1 10,3
Artificial crown	108	8,1
Thinning of root canal walls	406	30,6
Abutment for bridge restoration	313	23,6
Abutment for removable denture	200	15,1
4. Time elapsed since devitalization, years: ≤ 3 years ≤ 5 years ≤ 10 years > 10 years	359 606 182 19	30,8 52,0 15,6 1,6
5. Time elapsed since restoration, years: ≤ 3 years ≤ 5 years ≤ 10 years > 10 years	126 304 150 75	19,2 46,4 22,9 11,5
6. Time elapsed since crown or bridge restoration placement, years: ≤ 3 years ≤ 5 years ≤ 10 years > 10 years	123 207 34 57	29,2 49,2 8,1 13,5
7. Time elapsed since removable denture placement, years: ≤ 3 years ≤ 5 years ≤ 10 years > 10 years	78 99 13 10	39,0 49,5 6,5 5,0

 

RESULTS

Statistical analysis of the survey revealed that tooth fractures and cracks were identified in 12.1% of treated teeth and 10.2% of extracted teeth, averaging 11.1% (1,329 teeth). Cracks accounted for the majority of damage (60.4%, 803 teeth), whereas fractures comprised 39.6% (526 teeth).

Among affected teeth, incisors, cuspids, bicuspids, and molars accounted for 206 (15.5%), 22 (1.7%), 701 (52.7%), and 400 (30.1%) teeth, respectively, with bicuspids being the most frequently involved (Fig. 1). Maxillary teeth were affected more frequently than mandibular ones (62.5% [830 teeth] vs. 37.5% [499 teeth]). Root involvement was more common than crown involvement (59.1% [785 roots] vs 40.9% [544 crowns]). Longitudinal cracks and fractures were more common (68.2%, 906 teeth) than transverse ones (31.8%, 423 teeth).

 

Fig. 1. The frequency of identification of risk factors among teeth with cracks and fractures: а — topographical factors; b — factors of functioning; c — the presence of restoration structures.

 

Cracks and fractures were detected solely by radiography in 5.9% of cases (78 teeth) and by computed tomography in 9.7% of cases (129 teeth).

The majority of affected teeth (87.7%, 1,166 teeth) were previously devitalized (Fig. 2). Only 5.3% of cracked or fractured teeth (71 teeth) were mobile. The majority of affected teeth were under excessive occlusal load due to unreplaced missing teeth (79.2%, 1,052 teeth). Bruxism and temporomandibular dysfunction contributed to 29.2% of cases (388 teeth), and occlusal interferences to 12.7% of cases (169 teeth). Jawbone resorption near cervical line exceeding 30% of root length was found in 30.1% (400 teeth), whereas periapical bone resorption was present in only 9.3% (124 teeth).

 

Fig. 2. The frequency of fractures and cracks depending on the service life from the moment of tooth devitalization, tooth restoration, fixation of the crown or bridge prosthesis, application of a removable prosthesis.

 

Extensive loss of coronal tooth structure (more than 50% of the occlusal surface) was reported in 76.3% (1,014 teeth). In 20.5% (208 teeth), cavities extended to the dental cervix. Teeth restored with composite fillings showed a lower fracture rate (49.3%, 655 teeth). Teeth with core buildup using metal or glass fiber posts were affected in 21.9% (291), 21.1% (280), and 10.3% (137) of cases, respectively. Root wall thinning was detected in 30.6% of fractured or cracked teeth (406 teeth). Artificial crowns were present in 8.1% (108 teeth), and 23.6% (313 teeth) served as abutments for bridge restorations. Another 15.1% (200 teeth) were abutments for partial removable dentures.

The time elapsed since devitalization in teeth with fractures or cracks was distributed as follows: ≤ 3 years in 3.8% (359 of 1,156 devitalized teeth), ≤ 5 years in 52.0% (606 teeth), ≤ 10 years in 15.6% (182 teeth), and > 10 years in 1.6% (19 teeth) (see Fig. 2). For teeth with composite restorations, fractures and cracks occurred ≤ 3 years in 19.2% (126 of 655 teeth), ≤ 5 years in 46.4% (304 teeth), ≤ 10 years in 22.9% (150 teeth), and > 10 years in 11.5% (75 teeth). In teeth restored with artificial crowns (including abutments for bridge restorations), fractures and cracks developed ≤ 3 years after placement in 29.2% of cases (123 of 421 teeth), ≤ 5 years in 49.2% (207 teeth), ≤ 10 years in 8.1% (34 teeth), and > 10 years in 13.5% (57 teeth). Fractures and cracks in abutment teeth engaged by clasps or attachments of removable partial dentures occurred ≤ 3 years after prosthesis placement in 39.0% of cases (78 of 200 abutment teeth), ≤ 5 years in 49.5% (99 teeth), ≤ 10 years in 6.5% (13 teeth), and > 10 years in 5.0% (10 teeth).

DISCUSSION

According to the surveyed dentists, cracks and fractures were detected in more than 10% of extracted and treated teeth, indicating a relatively high frequency. The primary contributing factors included prior devitalization and excessive occlusal load due to unreplaced missing teeth, extensive coronal destruction, root wall thinning, and long intervals following devitalization, restoration, or prosthetic treatment. More than half of the cracks were longitudinal. Cracks and fractures occurred more commonly in maxillary bicuspids.

CONCLUSION

Based on the survey findings, cracks and fractures were detected in 6.7% and 4.4% of extracted and treated teeth, respectively. The roots of maxillary bicuspids were the most common site (59.1%), with longitudinal cracks accounting for 68.2%. In 15.6% of cases, cracks and fractures were only identified by radiography or CT imaging.

A total of 87.7% of cracks and fractures were observed in devitalized teeth; 79.3% occurred in patients with unreplaced missing teeth, cavities, or restorations involving more than 50% of the occlusal surface (76.3% and 49.3%, respectively); 30.6% were found in teeth with root wall thinning. At least 65.0% of structural failures occurred within five years after devitalization, restoration, or prosthetic treatment.

These findings may serve as a basis for predicting the long-term risk of cracks and fractures following dental tissue treatment.

ADDITIONAL INFORMATION

Funding sources: The authors declare no external funding for this study or its publication.

Disclosure of interests: The authors declare no explicit or potential conflicts of interests associated with the publication of this article.

Author contributions: All authors made significant contributions to the conceptualization, investigation, and preparation of the manuscript. All authors reviewed and approved the final version prior to publication. The authors contributed as follows: E.A. Olesova: questionnaire development; A.A. Ilyin: thematic justification based on published data; E.V. Glazkova: project administration; A.A. Popov: analysis of survey findings; S.P. Iarilkina: statistical analysis of survey findings; S.D. Arutyunov: conceptualization.

About the authors

Emilia A. Olesova

State Research Center — Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Author for correspondence.
Email: emma.olesova@mail.ru
ORCID iD: 0000-0003-4511-6317
SPIN-code: 5767-9158
Russian Federation, 46 Zhivopisnaya street, 123098 Moscow

Alexander A. Ilyin

State Research Center — Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Email: Alex2017ilyin@yandex.ru
ORCID iD: 0000-0002-8021-4599
SPIN-code: 2615-2137

MD, Dr. Sci. (Medicine), Professor

Russian Federation, 46 Zhivopisnaya street, 123098 Moscow

Sergey D. Arutyunov

Russian University of Medicine

Email: sd.arutyunov@mail.ru
ORCID iD: 0000-0001-6512-8724
SPIN-code: 1052-4131

MD, Dr. Sci. (Medicine), Professor

Russian Federation, Moscow

Elena V. Glazkova

State Research Center — Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Email: pozharskaya_lena@mail.ru
ORCID iD: 0000-0002-9825-4935
SPIN-code: 5304-9137

MD, Cand. Sci. (Medicine), Associate Professor

Russian Federation, 46 Zhivopisnaya street, 123098 Moscow

Arsen A. Popov

State Research Center — Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Email: surgeon.stom@gmail.com
ORCID iD: 0009-0002-3441-3068
SPIN-code: 6352-4877
Russian Federation, 46 Zhivopisnaya street, 123098 Moscow

Svetlana P. Iarilkina

State Research Center — Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency

Email: yarilkina@mail.ru
ORCID iD: 0000-0001-6182-3965
SPIN-code: 8663-0213

MD, Cand. Sci. (Medicine), Associate Professor

Russian Federation, 46 Zhivopisnaya street, 123098 Moscow

References

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