The Correlation Between Cracked Teeth and National Insurance Coverage of Dental Implants in South Korea: A Retrospective Cohort Analysis
Abstract
1. Introduction
2. Materials and Methods
2.1. Ethical Considerations
2.2. Data Processing
2.3. Case Selection
2.4. Collected Data
2.5. Statistical Analysis
3. Results
3.1. Trends in Cracked Teeth Incidence by Year
3.2. Analysis of Correlations Between Risk Factors and NHI Coverage of Dental Implants for Older Adults
4. Discussion
4.1. Evolving Treatment Paradigms and Diagnostic Challenges in Cracked Teeth
4.2. Influence of Health Policy and Systemic Factors on Treatment Decisions
4.3. Biomechanical Considerations: Implant Occlusion and Adjacent Tooth Health
4.4. Global Trends and Stress-Related Dental Issues, Including COVID-19 Impact
4.5. Limitations and Future Directions
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
Abbreviations
NHI | National Health Insurance |
CDW | Clinical Data Warehouse |
EDP | Enterprise Data Platform |
ICD | International Statistical Classification of Diseases and Related Health Problems |
KCD | Korean Standard Classification of Diseases |
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Country | Public Coverage for Older Adults | Key Aspects of Dental and Prosthodontic Coverage |
---|---|---|
South Korea | Yes | Publicly covered for seniors aged 65+. Up to two implants per lifetime covered with 30% co-payment. |
Sweden | Yes | Fixed public subsidies for all general dental treatment, including prosthodontics. Additional support for high-cost cases. |
Germany | Yes | Wide public coverage for basic/conservative treatments. Partial coverage for prosthodontics (50–60%). |
USA | No | Primarily privately funded; only 5% publicly funded. |
Spain | No | No public funding for dental care, except extractions. |
Switzerland | No | No general public coverage; exceptions for severe diseases. Low private coverage uptake. |
Variable | Subgroup |
---|---|
Sex | F, M |
Age group | 20–29, 30–39, 40–49, 50–59, 60–69, ≥70 |
Sign and Symptoms | Absent, Present |
Biting pain | Absent, Present |
Pulpitis | Absent, Present |
Pulp status | Normal, Reversible pulpitis, Irreversible pulpitis + Pulp necrosis + Pulpless |
Gingival swelling | Absent, Present |
Apical lesion | Absent, Present |
Pocket depth | <3 mm, 4–6 mm, >6 mm |
Treatment | endodontic tx. + crown, resin + crown, resin + crown → endodontic tx. |
Procedure | endodontic tx. + crown, resin + crown, resin + crown → endodontic tx. |
Location of teeth | Mandibular first molar, Mandibular first premolar, Mandibular second molar, Mandibular second premolar, |
Maxillary first molar, Maxillary first premolar, Maxillary second molar, Maxillary second premolar |
Year | Total Crown No. | Total Crack No. | Crack% |
---|---|---|---|
2014 | 553 | 133 | 24.1 |
2015 | 575 | 155 | 27.0 |
2016 | 550 | 176 | 32.0 |
2017 | 588 | 181 | 30.8 |
2018 | 670 | 207 | 30.9 |
2019 | 609 | 225 | 36.9 |
2020 | 631 | 274 | 43.4 |
2021 | 492 | 189 | 38.4 |
2022 | 376 | 152 | 40.4 |
p value | <0.001 | ||
Adj. p value | <0.001 | ||
Reg. coef. (95% CI) | 2.148 (1.449–2.848) | ||
Reg. coef. p value | <0.001 |
Period | Total | Crack | No Crack | p Value |
---|---|---|---|---|
Before insurance | 1128 (22.4) | 288 (25.5) | 840 (74.5) | <0.001 |
After insurance | 3916 (77.6) | 1404 (35.9) | 2512 (64.1) | |
Total | 5044 (100.0) | 1692 (33.5) | 3352 (66.5) | |
p value | <0.001 |
Variable | Subgroup | Before Insurance 2014–2015 | After Insurance I 2016–2019 | After Insurance II 2020–2022 | Total | p Value | p Value for Proportion Test |
---|---|---|---|---|---|---|---|
N(%) | 289 (17.2) | 791 (47.0) | 603 (35.8) | 1683 | |||
Sex | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | 0.286 | |
F | 146 (50.7) | 418 (53.0) | 335 (56.0) | 899 (53.7) | 0.286 | ||
M | 142 (49.3) | 371 (47.0) | 263 (44.0) | 776 (46.3) | 0.286 | ||
Age group | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | 0.017 | |
20–29 | 7 (2.4) | 19 (2.4) | 16 (2.7) | 42 (2.5) | 0.947 | ||
30–39 | 44 (15.3) | 80 (10.1) | 56 (9.4) | 180 (10.7) | 0.022 | ||
40–49 | 55 (19.1) | 142 (18.0) | 82 (13.7) | 279 (16.7) | 0.050 | ||
50–59 | 75 (26.0) | 215 (27.2) | 152 (25.4) | 442 (26.4) | 0.737 | ||
60–69 | 75 (26.0) | 210 (26.6) | 179 (29.9) | 464 (27.7) | 0.309 | ||
≥70 | 32 (11.1) | 123 (15.6) | 113 (18.9) | 268 (16.0) | 0.011 | ||
Sign and Symptoms | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | <0.001 | |
Absent | 94 (32.6) | 392 (49.7) | 301 (50.3) | 787 (47.0) | <0.001 | ||
Present | 194 (67.4) | 397 (50.3) | 297 (49.7) | 888 (53.0) | <0.001 | ||
Biting pain | Total | 289 (17.2) | 791 (47.0) | 603 (35.8) | 1683 (100.0) | <0.001 | |
Absent | 139 (48.1) | 549 (69.4) | 399 (66.2) | 1087 (64.6) | <0.001 | ||
Present | 150 (51.9) | 242 (30.6) | 204 (33.8) | 596 (35.4) | <0.001 | ||
Old restoration | Total | 289 (17.2) | 791 (47.0) | 602 (35.8) | 1682 (100.0) | 0.076 | |
Absent | 134 (46.4) | 390 (49.3) | 260 (43.2) | 784 (46.6) | 0.076 | ||
Present | 155 (53.6) | 401 (50.7) | 342 (56.8) | 898 (53.4) | 0.076 | ||
Cervical abrasion | Total | 289 (17.2) | 791 (47.0) | 603 (35.8) | 1683 (100.0) | 0.015 | |
Absent | 263 (91.0) | 729 (92.2) | 528 (87.6) | 1520 (90.3) | 0.015 | ||
Present | 26 (9.0) | 62 (7.8) | 75 (12.4) | 163 (9.7) | 0.015 | ||
Pulpitis | Total | 289 (17.2) | 791 (47.0) | 603 (35.8) | 1683 (100.0) | 0.782 | |
Absent | 209 (72.3) | 584 (73.8) | 436 (72.3) | 1229 (73.0) | 0.782 | ||
Present | 80 (27.7) | 207 (26.2) | 167 (27.7) | 454 (27.0) | 0.782 | ||
Pulp status | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | <0.001 | |
Normal | 135 (46.9) | 451 (57.2) | 350 (58.5) | 936 (55.9) | 0.003 | ||
Reversible pulpitis | 46 (16.0) | 115 (14.6) | 113 (18.9) | 274 (16.4) | 0.096 | ||
Irreversible pulpitis + Pulp necrosis + Pulpless | 107 (37.2) | 223 (28.3) | 135 (22.6) | 465 (27.8) | <0.001 | ||
Gingival swelling | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | 0.599 | |
Absent | 274 (95.1) | 761 (96.5) | 573 (95.8) | 1608 (96.0) | 0.599 | ||
Present | 14 (4.9) | 28 (3.5) | 25 (4.2) | 67 (4.0) | 0.599 | ||
Apical lesion | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | 0.144 | |
Absent | 256 (88.9) | 682 (86.4) | 537 (89.8) | 1475 (88.1) | 0.144 | ||
Present | 32 (11.1) | 107 (13.6) | 61 (10.2) | 200 (11.9) | 0.144 | ||
PD | Total | 289 (17.2) | 791 (47.0) | 602 (35.8) | 1682 (100.0) | 0.265 | |
<3 mm | 206 (71.3) | 615 (77.7) | 462 (76.7) | 1283 (76.3) | 0.082 | ||
4–6 mm | 70 (24.2) | 147 (18.6) | 115 (19.1) | 332 (19.7) | 0.106 | ||
>6 mm | 13 (4.5) | 29 (3.7) | 25 (4.2) | 67 (4.0) | 0.797 | ||
Treatment | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | <0.001 | |
endo + crown | 217 (75.3) | 465 (58.9) | 207 (34.6) | 889 (53.1) | <0.001 | ||
resin + crown | 71 (24.7) | 324 (41.1) | 390 (65.2) | 785 (46.9) | <0.001 | ||
resin + crown → endo | 0 (0.0) | 0 (0.0) | 1 (0.2) | 1 (0.1) | 0.406 | ||
Procedure | Total | 288 (17.2) | 789 (47.1) | 598 (35.7) | 1675 (100.0) | <0.001 | |
endo + crown | 213 (74.0) | 435 (55.1) | 193 (32.3) | 841 (50.2) | <0.001 | ||
resin + crown | 71 (24.7) | 324 (41.1) | 388 (64.9) | 783 (46.7) | <0.001 | ||
resin + crown → endo | 4 (1.4) | 30 (3.8) | 17 (2.8) | 51 (3.0) | 0.117 | ||
Location of teeth | Total | 289 (17.2) | 790 (47.1) | 598 (35.7) | 1677 (100.0) | 0.871 | |
Mandibular first molar | 53 (18.3) | 184 (23.3) | 147 (24.6) | 384 (22.9) | 0.109 | ||
Mandibular first premolar | 3 (1.0) | 9 (1.1) | 6 (1.0) | 18 (1.1) | 0.969 | ||
Mandibular second molar | 71 (24.6) | 187 (23.7) | 123 (20.6) | 381 (22.7) | 0.280 | ||
Mandibular second premolar | 10 (3.5) | 22 (2.8) | 15 (2.5) | 47 (2.8) | 0.723 | ||
Maxillary first molar | 74 (25.6) | 173 (21.9) | 137 (22.9) | 384 (22.9) | 0.439 | ||
Maxillary first premolar | 12 (4.2) | 39 (4.9) | 30 (5.0) | 81 (4.8) | 0.838 | ||
Maxillary second molar | 44 (15.2) | 125 (15.8) | 99 (16.6) | 268 (16.0) | 0.867 | ||
Maxillary second premolar | 22 (7.6) | 51 (6.5) | 41 (6.9) | 114 (6.8) | 0.798 | ||
Caries | Total | 288 (17.2) | 788 (47.1) | 598 (35.7) | 1674 (100.0) | 0.015 | |
Absent | 211 (73.3) | 603 (76.5) | 416 (69.6) | 1230 (73.5) | 0.015 | ||
Present | 77 (26.7) | 185 (23.5) | 182 (30.4) | 444 (26.5) | 0.015 |
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Kahm, S.H.; Shim, Y.; Yang, S. The Correlation Between Cracked Teeth and National Insurance Coverage of Dental Implants in South Korea: A Retrospective Cohort Analysis. J. Clin. Med. 2025, 14, 5507. https://doi.org/10.3390/jcm14155507
Kahm SH, Shim Y, Yang S. The Correlation Between Cracked Teeth and National Insurance Coverage of Dental Implants in South Korea: A Retrospective Cohort Analysis. Journal of Clinical Medicine. 2025; 14(15):5507. https://doi.org/10.3390/jcm14155507
Chicago/Turabian StyleKahm, Se Hoon, YoungHa Shim, and SungEun Yang. 2025. "The Correlation Between Cracked Teeth and National Insurance Coverage of Dental Implants in South Korea: A Retrospective Cohort Analysis" Journal of Clinical Medicine 14, no. 15: 5507. https://doi.org/10.3390/jcm14155507
APA StyleKahm, S. H., Shim, Y., & Yang, S. (2025). The Correlation Between Cracked Teeth and National Insurance Coverage of Dental Implants in South Korea: A Retrospective Cohort Analysis. Journal of Clinical Medicine, 14(15), 5507. https://doi.org/10.3390/jcm14155507