INTRODUCTION

Non-carious cervical injuries (LCNC) are injuries that result from the loss of dental structure in the cervical region not related to caries injury. It has a multifactorial etiology; the combinations of factors contribute to the cause of the problem, so it is considered complete for both the studio and the treatment¹. The etiological factors of this injury may be abrasion, erosion, friction, friction or asociation^2-5.

The LCNC reside in a group of more complex lesions in the dental clinic, mainly in the identification of the causative agent and the treatment offered. Several factors may contribute to the appearance and development of these lesions, but they do not necessarily act as a direct cause of them. Knowledge of the etiology of these lesions is essential for effective and safe treatment, as well as to help prevent the development and progression of new lesions⁶.

Clinical studies are critical to clarify and validate hypotheses of how LCNCs are initiated, providing a solid basis for clinical diagnoses7. The perception and impact of the mechanisms of injury and their interactions become an effective guide for clinicians to evaluate their patients^8,9.

The mechanical maintenance of oral hygiene can contribute taking into account that the direction and intensity of the forces applied to the teeth are important factors for the appearance^10,11, age and sex can influence the prevalence of injuries¹².

Occlusion is another important factor. The stress on the interface of the enamel and dentin at the junction of the cement enamel may allow the appearance of LCNC^13,14. Diet is another factor in the appearance of lesions¹⁵.

The objective of this study was to verify the clinical and epidemiological characteristics, as well as the risk factors of LCNC in adult individuals.

 

Material and method

The study was presented to the Research Ethics Committee of the Metropolitan University of Santos, UNIMES and approved under the number 1,809,698. Ninety-six individuals were evaluated and interviewed for epidemiological analysis and intraoral clinical examinations to evaluate the clinical characteristics of 300 teeth with non-carious cervical lesions. People with one or more dental elements with non-carious cervical lesions were included in the study. Individuals with bimaxillary total prosthesis and under 18 years were excluded from the study.

The interviews and the clinical examination were applied by a previously trained examiner to avoid possible reading errors.

The interviews were designed to analyze the following aspects: gender, use of prostheses, brush type, brushing direction, history of gastrointestinal disorders, frequency of eating or eating acidic foods, history of harmful habits, history of parafunction and daily medication use. For the intraoral clinical examination, clinical clamps (Duflex®), scanner (Duflex®), mirror No. 5 (Duflex®), Palmer clamp (Duflex®), millimeter scan probe No. 1 (Duflex®), articulation paper were used in strips (Accufilm ll).

For the analysis of the types of occlusal contact points in the oral-lingual LCNC support elements, contacts of three types were analyzed: Contact A (crushing slope of the upper teeth in contact with the smooth slope of the lower teeth); contact B (crushing slope of the upper teeth against crushing slope of the lower teeth and contact C (smooth slope of the upper teeth with crushing slope of the lower teeth). Certain records of contact points were analyzed in all LCNC elements by means of of carbon strips and Palmer clamps (Duflex®) with patients positioned maxillary-mandibular relationship of central occlusion (Figure 1).

Figure 1. Illustration of contact points

For the analysis of the occlusive guides, the visual evaluation was used and confirmed by paper to articulate in strips (Figure 2)

Figure 2. Deocclusive guide - Right Laterality

The characteristics of the injury were analyzed by means of a millimeter probe placed in the center of the injuries and perpendicular to the long axis of the tooth, according to the Index of dental wear proposed by Smith and Knight (Figure 3)¹⁶.

Figure 3. Depth of the Injury

The intra-examiner error was calculated with CI (> 95%) by the Kappa method to observe the intra-examiner agreement by repeating the measurements and recording the contacts. All tests were tabulated and their results expressed in tables.

 

Results

Regarding to the female and male gender, there was a significant prevalence for the female gender (Figure 1) with a prevalence ratio (PR) of 0.62.

Picture 1. Prevalence ratio regarding gender

There was a significant prevalence among prosthetic users (Graph 2) and the presence of LCNC with a PR of 0.87. Among the evaluated patients who used some type of prosthesis, the prevalence of partial removable prosthesis users with RP of 0.45.

Picture 2. Prevalence ratio for prosthetic users

Regarding to oral hygiene habits, the following questions were asked: the type of hair used was soft, medium or hard bristles (Graph 3); the frequency of daily picks varied once a day, from time to time, three times and four times the worst (Graph 4); type of zip direction performed with horizontal, vertical and combined movement (Graph 5).

No significant changes were found in the results regarding the presence of the lesion and oral hygiene habits

Picture 3. Prevalence ratio regarding the type of brush

Pcture 4. Reason for prevalence regarding brushing direction

Picture 5. Prevalence ratio regarding Brushing Frequency

Regarding to the history of gastrointestinal disorders (Graph 6), there was a significant prevalence in patients with gastrointestinal disorders and the presence of LCNC with RP of 0.56.

Picture 6. Reason for prevalence regarding the History of Pathologies

Regarding to parafunctional habits (Graph 7), a high prevalence was observed that associates these habits and the presence of LCNC with RP of 0.71. Among those evaluated, bruxism prevailed with a PR of 0.36.

Picture 7. Reason for prevalence in reference to Parafunctional Habits

Regarding to eating habits, this study investigated the relationship between the intake of acidic drinks, fruits and / or citrus juices with the presence of LCNC (Graph 8). There was a high prevalence of acid consumption habits and the presence of LCNC with PR of 0.93.

Picture 8. Reason for prevalence regarding ingestion of acidic beverages

Regarding to harmful habits (Table 9), there was no high prevalence of these habits and the presence of LCNC, with RP of 0.26.

Picture 9. Reason for prevalence regarding harmful habits

Regarding to the use of medications, the present study did not find a significant prevalence between the use of medications and the presence of LCNC (Graph 10), with a PR of 0.40.

Picture 10. Percentage in relation to the use of medications in Systemic conditions

Intraoral examinations containing the following "characteristics" were performed: deocclusion movements, right laterality (Graph 11) and Left (Graph 12); the types of occlusal contacts A, B, C and combined (Figure 13); The depth of the lesion is less than 1 mm, greater than 1 mm and greater than 2 mm (Figure 14); with respect to the elements with cervical lesion as a removable partial denture retainer (PPR), adjacent to the prosthetic space and fixed partial prosthetic abutment (PPF) (Figure 15), and with respect to the group of teeth that are anterior, canine, premolar and molars (Graph 16).

There was an expressive prevalence with respect to occlusion characteristics in the lateral movements of the canine guide and the presence of LCNC (Graphs 11 and 12) with a PR of 0.98.

Picture 11. Prevalence ratio regarding Right Laterality movements

Picture 12. Prevalence ratio regarding the movements of the left laterality

Regarding the types of contact, there was a significant prevalence of occlusal instability and the presence of LCNC (Figure 13), with a PR of 0.94. Among the elements evaluated with occlusal instability, there was a greater predominance for A contact with RP of 0.40.

Picture 13. Razón de prevalencia referente a los tipos de contatos

In the characteristics of the lesion regarding to depth, a higher prevalence was observed for the defect less than 1 mm deep (Graph 14), with a PR of 0.43.

Picture 14. Percentage in relation to injury depth

Picture 15. Prevalence ratio referring to the elements with LCNC.

The evaluation of the group of teeth (Graph 16) showed a high prevalence of premolars and the presence of LCNC with PR of 0.54.

Picture 16. Razón de prevalencia referente al grupo de dientes; Prevalence ratio regarding the group of teeth

 

Reliability fo the measurement

With respect to the measurements of the depth of the lesion and the types of occlusal contacts, performed in 2 moments (T1 - first moment as a complete sample; T2 - 30 days after the first registration) for 20 patients to assess the reliability of the data Registered patients were analyzed by intraclass correlation (ICC).

Table 1: Reliability of assessments for depth of injury and types of occlusal count using ICC

Discussion

Analyzing the results obtained in 96 patients with cervical lesions, it is found that, with respect to gender, there was a significant prevalence of women, with a prevalence rate of 0.25 more than men. Some studies have reported a higher prevalence in men10,12 and in other gender studies was irrelevant15,19.

With regard to the type of prosthesis, in the hub related to the type of retention of the PPR with the LCNC20. In this study, the users of prostheses had a significant prevalence of 0.87, being more prevalent in PPR with 0.46.

As for oral hygiene habits, in the hub a direct relationship with the presence of cervical injuries, as well as the frequency and direction of the spine, which depends on the association with other factors related to the presence of cervical injuries, such as corroboran some authors4. In another study it is found that the manual belt has a higher prevalence in the gingival recession with the use of hard pins5 as compared to an electric belt11.

Regarding to gastrointestinal upheavals, this studio will find that there is a relationship between gastrointestinal upheavals and the presence of LCNC. Another studio coincides with the result of this work18 indicating that patients with gastric reflux are more susceptible to mechanical wear.

With reference to parafunctional habits, studies indicate a direct association with these habits and the presence of LCNC3,5. The collaboration with these studies identified that there is a relationship between parafunctional habits and injuries, presenting the result of a prevalence table 0.36 for bruxism and 0.35 for presentation.

As far as food habits are concerned, researchers investigated the link between cold carbonated drinks, fruits and fruit juices with the LCNC formation, but there was no correlation between them4. In contrast, in this study there was a significant prevalence among the consumption of acidic foods and the presence of non-carious cervical injuries, where 0.93 of the analyzed patients contain this habit.

With regard to harmful habits, in this studio in the hub a direct relationship with the LCNC, however, in another studio hubo a relationship between the LCNC and the harmful habits, in which 58% of the subjects bite objects and 21 % were cigarettes consumers5.

Regarding the use of medications, I cannot relate to the presence of LCNC with a prevalence ratio of 0.40, however, another study describes that the intake of medications increases hyposalivation and interferes with the pH of the saliva, causing more acid and increase in dental wear17.

As for the characteristics of the occlusion, a study found that 63% of patients evaluated with LCNC had group function guidance in lateral mandibular movements, concluding that the direction and intensity of strength applied to patients could be contributing to them. the appearance of the students. cervical lesions not carious10. In this study, with respect to the orientation of the group function in the mandibular movements of the lateral side, there was a prevalence rate of 0.70 of the lesions occurred in the canine guide, no, however I have a direct relationship with the cause of the injury.

In the elements with cervical injury, the investigation showed a high prevalence with respect to the instability of dental occlusion, with a predominance in contact A containing 0.40, followed by contact B of 0.21 and contact C with 0.20. However, horizontal strengths were exactly harmful because they generate contact and discharge strengths. Another study collaborates with the results obtained in this study that the lateral and occlusal strengths cause the flexion of the cusp and the causes of the rupture of the dental structure in the cervical region21.

With respect to the injury depth factor, in the present study, a higher prevalence in defects of depth of less than 1 mm was identified in elements with LCNC, another studio also found an increase in the prevalence of injuries in depth of less than 1 mm3, The elements with a minimum contour loss and defects of less than 1 mm must remain under regular dentist control. Injuries with larger defects of 1 mm and 2 mm in depth need restorative treatment18.

Finally, with respect to the group of patients, the present study shows that 0.54 of the patients evaluated have the highest concentration of LNC in premolars and molars. Other studies coincide that the largest group of affected teeth were premolar and molar3,4,10,15.

 

Conclusion

According to the results obtained in this study, it is possible to conclude that people with a lesion depth less than 1 mm, alcohol consumption habits, users of dental prostheses, people with parafunctional habits and people with gastrointestinal upheavals a high prevalence of LCNC. Therefore, indicate that the etiology of these injuries is multifactorial.

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	David Montero; https://orcid.org/0000-0001-7435-802X