Scaling vs Comprehensive Periodontal Therapy in Reducing Serum Lipid Levels in Patients with Hyperlipidemia

Introduction

Hyperlipidemia is often seen as a key factor in the development of non-communicable diseases. Atherosclerotic changes related to elevated serum lipid levels often contribute to coronary heart disease. It is opined that chronic inflammation can dysregulate lipoprotein metabolism and significantly impact lipid levels.¹ Localized infection, such as periodontitis, have been observed to potentiate cytokines and hormones, altering lipid metabolism.² Therefore, assessing periodontal changes in clinically relevant scenarios of altered lipid profile conditions, such as hyperlipidemia is warranted.

Earlier investigations have hinted that subjects with poorer periodontal status had elevated levels of triglyceride (TG) and low-density lipoprotein (LDL), than those who had good periodontal health.^3,4 Bacterial stimulation in unattended periodontal disease induces a heightened inflammatory mediator response and dyslipidemia.^5,6 This periodontal bacterial load is purported to be exclusively involved in altering serum lipids,⁷ which has encouraged studies relating the bearing of dental scaling and root planing on serum lipids.^8,9

Conventional management of diseases of the periodontium has chiefly focused on reducing sites for microbial recolonization through non-surgical and surgical methods. The research in this area has provided a glimpse of the outcomes of non-surgical therapy. Scarce data exists on comparative studies between surgical versus non-surgical modes of treatment, in particular, coronal scaling only, on lipid profile changes. Surgical treatment may be more beneficial in sites with deep pockets initially. Reports suggest effective subgingival debridement can positively affect the metabolism of lipids and improve systemic inflammatory marker levels.¹⁰

Earlier studies have not attempted to consider standard clinical periodontal indices like plaque index (PI), gingival index (GI), and probing depth (PD) as possible indicators of inflammation and evaluate their recovery with serum lipids. The ‘systematic review and metaanalysis’ finds data to be convincing enough to relate periodontitis, metabolic syndrome, and obesity.¹¹

Based on the above observations, the present study intended to study the impact of comprehensive surgical periodontal management on serum lipids, along with the correlation of serum-lipids with standard clinical indices (PI, GI, PD), Body Mass Index (BMI), and the waisthip ratio (WHR) in hyperlipidemic patients receiving comprehensive periodontal treatment versus scaling alone.

Materials and Method

The clinical trial was conducted in the Department of Periodontology over sixteen months after availing institutional ethical approval (CTRI/2016/03/006700). Inclusion into the study warranted written, informed consent from those patients requiring treatment for their periodontal condition. A simple randomization technique (coin toss method) allocated the participants into parallel study groups.

Sample size estimation used a large effect size with 80% power and a 5% level of significance, permitting approximately 14 subjects in each group. The study comprised patients in the age group of 30 – 65 years, with recently diagnosed hyperlipidemia, and not on any cholesterol-lowering medications. Pregnancy, prolonged inflammatory conditions (other than periodontitis), intake of chemotherapeutic agents, and tobacco use were exclusion criteria. Periodontitis was considered if involved sites had Probing Pocket depth (PD) ≥5 mm, with Clinical Attachment Loss (CAL) of ≥1 mm (in ≥ 2 quadrants).

An experienced clinician, unaware of the treatment group allocation checked the patients’ weight, height, and waist-hip circumference for calculation of Body Mass Index (BMI) and waist-hip ratio. An electronic balance (Essae, India) was utilized for determining body weight, with subjects wearing light clothes and no shoes or socks. For measurement of height, the subjects were asked to stand with their feet together against a wall with a scale and measured using tape. Body Mass Index (BMI) was calculated using the expression: BMI=Weight (kg)/ Height (m)² .

The periodontal status assessment used standard clinical parameters such as Plaque Index (PI),¹² Gingival Index (GI),13 and PD. The patients’ medical records provided the baseline lipid levels. All variables were measured again after three months of intervention.

Fifteen patients received supragingival scaling, followed by a demonstration of the Modified Bass method of brushing (group A) during the first visit to the department. After fifteen days, quadrant-wise subgingival scaling and root planing (SRP) was carried out such that complete treatment was ensured within 24 hours. Subsequently, the patients’ received either curettage or open flap debridement, based on clinical judgment, followed by oral-hygiene instructions, emphasizing interdental plaque control. As a procedure, curettage was performed on the root surfaces, soft tissue lining and was also used for osseous defect debridement. Root planing/root curettage, performed with a curette, is necessary to reduce inflammation and allow for healing. When done to remove the epithelial lining, it is purported to have no additional benefit over scaling and root planing alone. However, during periodontal surgery, curettage is an essential step in the debridement of osseous defects to remove the granulation tissue over the defects. Wherever appropriate, this procedure may have significant regenerative potential.¹⁴

In Group B, fifteen randomly selected patients received scaling along with instructions on the use of the Modified Bass method of brushing and interdental cleaning at the first visit (Figure 1 – Consort flowchart). Further periodontal treatment, deemed necessary, was deferred till after the conclusion of the study.

Statistical Analysis

SPSS software (version 15) analyzed the data. The Shapiro-Wilk test evaluated the normality of the data. The paired t-test analyzed within-group differences from baseline to three months, and between group differences at the end of the study. Statistical significance was established at a p-value of <0.05. Pearson correlation coefficient summarized the correlation between periodontal parameter alterations and serum lipid levels.

Results

The patients in Group A were of mean age 47±10.21 years, with ten males and five females. Group B consisted of nine males and six females within the age range of 49.93±12.11 years, indicating no significant age and gender differences.

The mean Plaque Index at baseline was 1.96±0.40 and 1.85±0.38 in groups A and B respectively. This parameter showed no significant difference for both the groups at baseline. The mean Plaque Index post-treatment was 0.65±0.24 and 1.67±0.39 in the test and control groups respectively. Similarly, the mean Gingival Index at baseline was 1.95±0.37 and 1.94±0.37, whereas the mean Gingival Index at the three-month follow-up was 0.61±0.19 and 1.82±0.26 in groups A and B respectively. The intra group decrease in the mean Gingival Index was statistically significant for group A than group B (p<0.001) (Table 1). At baseline, the mean Probing Depth was 6.08±1.01 and 5.66±0.87 in groups A and B respectively, while at 3 months, it was 2.96±0.34 and 5.63±1.04 respectively. The overall decrease in the probing depth was statistically significant for group A than group B (p<0.001) (Table 1).

The mean serum total cholesterol level at baseline was 248.00±26.30 mg/dl and 246.40±26.09 mg/dl in groups A and B respectively. The mean serum total cholesterol level at the three-month follow up was 192.53±29.78 and 237.80±41.18 in groups A and B respectively. Significant reduction in the total cholesterol levels was evident from baseline to three months for group A compared to group B (p<0.001). The mean serum triglyceride level at baseline was 176.73±36.17 mg/dl and 166.47±43.26 mg/dl in groups A and B respectively, showing no statistically significant difference. The mean serum triglyceride level at the three-month followup was 154.93±41.35 and 178.13±67.51 in groups A and B respectively. No significant reduction was seen in the triglyceride values pre and post-treatment for group A (p=0.109). However, group B showed a rise in triglyceride levels during the study period, but this was not statistically significant. The mean serum low-density lipoprotein level at baseline was 168.93±25.49 mg/dl and 157.80±20.50 mg/dl in groups A and B respectively. This parameter was not different for both the groups at baseline. The mean serum low-density lipoprotein level at three months was 124.47±25.13 and 146.07±35.09 in groups A and B respectively. The mean low-density lipoprotein levels significantly declined from baseline to three months for group A compared to group B (p<0.001). Mean serum high-density lipoprotein levels at baseline were 37.47±6.60 mg/dl and 37.47±6.90 mg/ dl in groups A and B respectively. This parameter was not significantly different for the two groups at baseline. The mean serum high-density lipoprotein level at three months follow-up was 41.73±7.28 and 37.93±5.50 in groups A and B respectively. While group B showed no change at all, group A showed a rise in HDL. Although not statistically significant (p=0.143), this increase is desirable clinically (Table 1).

The mean body mass index at baseline was 24.38±3.13 and 23.16±1.70 in groups A and B respectively. At baseline, this parameter was not signficantly different in the two groups. The mean Body Mass Index at three months was 23.68±2.70 and 23.30±1.57 in groups A and B respectively. While group A showed reduction, group B seemed to increase by three months. Although the differences in the mean Body Mass Index was minimal, it was significant for group A compared to group B (p=0.002). The mean waist-hip ratio at baseline was 0.88±0.06 and 0.88±0.06 in group A and group B respectively. This parameter was the same for both the groups at baseline. The mean waist-hip ratio at three months was 0.85±0.07 and 0.88±0.07 in groups A and B respectively. This mean waist-hip ratio was significantly different in group A compared to group B (p<0.001) (Table 1).

Hence, in group A, PI, GI, PD, TC, LDL, BMI, and waist-hip ratio (p<0.001) significantly differed at three months. On the other hand, PI was the only parameter showing a significant reduction at the end of the study period in Group B (p=0.006) (Table 1).

Between-group comparisons of % of improvement from the post to respective pretreatment levels showed subjects in group A having superior improvement in all the periodontal parameters (p<0.001), in addition to TC, LDL, BMI, and waist-hip ratio (p<0.05) (Table 2).

Furthermore, Plaque Index showed statistical correlation with all serum lipids, while Gingival Index and Probing Depth correlated with total cholesterol (Table 3).

Discussion

Adverse lipid profiles generally seen in metabolic syndrome and obesity have also been observed in chronic inflammatory conditions including periodontitis. The periodontal bacterial burden, in turn, can induce systemic levels of inflammatory mediators precipitating dyslipidemia. Based on these observations, this study evaluated the impact of comprehensive surgical periodontitis treatment on standard periodontal clinical indices, body mass index, waist-hip ratio and serum lipids. The study compared the effects of two conventional modes of periodontal treatment on serum lipids, in patients with hyperlipidemia. Comprehensive periodontal treatment improved the serum TC and LDL levels compared to supragingival scaling as a monotherapy.

Earlier studies revealed decreased TG, LDL, but an increase in HDL in patients receiving intensive periodontal therapy.^8,9,15 However, in these subjects, no surgical treatment was performed. Further, the subjects’ smoking status and concomitant treatment with other medications like doxycycline and statins were not accounted for, which might have influenced the findings in these studies.^16,17

On comparing the groups post-treatment, group A showed relatively enhanced improvement in periodontal parameters PI, GI and PD. Following complete periodontal therapy, healing is perceivably better owing to the more predictable decrease of subgingival microflora and possible gain in bone height and new attachment. In contrast, supragingival scaling alone cannot ensure instrument access to the base of the pocket allowing persistence and recolonization of the subgingival microflora, thus precluding complete resolution of the pocket. Aptly, Ribeiro et al. have affirmed that decrease in PD or CAL would not be apparent following a session of supragingival scaling.¹⁸

Our observations agree with the systematic review by Heitz‐Mayfield et al., where probing depth reduction was notably higher with flap procedures. ¹⁹ Furthermore, they opine that improvement in PD with surgical therapy is better with ‘initially deep pockets’, in patients receiving regular periodontal care and maintenance therapy.²⁰

Comprehensive surgical treatment involves effective pocket therapy, resulting in control and lessening of inflammation²¹ and decreased oxidative stress resulting in a beneficial impact on lipid profiles. Chronic inflammation can enhance hepatic lipogenesis and reduce the clearance of lipids.²² This is further aggravated by the upsurge of cytokines observed in periodontitis.²³ Furthermore, comprehensive treatment eliminates microbial niches and reduces the overall systemic inflammatory burden effectively. The significant fall in serum lipids following comprehensive treatment observed in the present study corroborates this opinion. Similar observations were made by Fu et al., where patients in one group received supragingival scaling & polishing, while another group had additional subgingival debridement of plaque through root planing.²⁴ The second group had significantly lesser TG and Tumor Necrosis Factor α (TNF-α) after two and half months, suggesting the effectiveness of completing periodontal therapy. However, Nibali et al. reported a contrasting perspective in cases of aggressive periodontitis. The patients underwent initial full mouth non-surgical debridement, followed by flap surgery after six weeks. They observed no variation in serum lipid levels three months after surgery.²⁵

Additionally, this study correlated standard clinical indices with serum lipids to establish its association with inflammation and consequential recovery. Here, Plaque Index correlated with serum lipids (TC, TG, HDL, and LDL), while GI and PD showed correlation with TC, further strengthening the association of lipids and inflammation. Previous research has shown similar observations.^17,26,27

Moreover, we observed a reduction in BMI and waist-hip ratio following comprehensive periodontal treatment. Cases with periodontitis and metabolic syndrome have determined oxidative stress as an underlying factor having sway on the extent of response to periodontal treatment. Therefore, the improvement in BMI/waisthip ratio observed in our study may be attributed to the alleviation of oxidative stress following comprehensive treatment.^28,29,30,31

Previous studies reported a connotation linking periodontitis with obesity.³² Fentoğluet et al. observed a similar drop in Body Mass Index consequent to administration of periodontal therapy to patients.³³ Juarez et al. reported that those presenting with an obese waistline, assessed with Waist hip ratio were 2.4 times more likely to develop periodontal disease.³⁴

Since these periodontal indices are standard indicators of recovery/ worsening of inflammation, it implies a prognostic role for lipids in periodontitis management, endorsed by improved lipid metabolism, following the decrease in cytokine load induced by inflammation.³⁵

General apathy towards the importance of dental health has been a significant deterrent towards improving oral health care. It is generally noted that patients often fail to report for follow-up after preliminary treatment for their presenting complaints. This may be due to the resolution of symptoms and the perception of generalized improvement. Therefore, many patients disregard the necessity of a complete and thorough maintenance protocol. The present study was designed to simulate this situation, where group B underwent only supragingival scaling with no follow-up protocol for maintenance, while group A received complete periodontal therapy and were kept on regular maintenance therapy.

The target population included patients having borderline hyperlipidemia and chronic periodontitis. Patients already on lipid-lowering agents were not included in the study due to the possibility of a reduction in lipid levels due to the medications, providing a source of bias. The subjects were followed over a period of three months from the baseline assessment, permitting sufficient time for complete healing of tissues as well as observation of lipid profile changes.

Conclusion

A comprehensive, therapeutic protocol comprising scaling and surgical treatment proved relatively more beneficial in concurrently improving serum lipids and standard clinical indices of periodontitis, particularly in patients with hyperlipidemia. Hence, we should preclude the state of chronic inflammation evident in periodontitis, while managing borderline hyperlipidemia. Further, an altered periodontal index can indicate a need for screening of the lipid profile.

Conflict of interest

None.