*2.4. Lipid Profiles*

Changes in lipid profiles between baseline and the 3- and 6-month follow-ups have been depicted in Table 2.



TC: total cholesterol; TG: triglyceride; LDL: low-density lipoprotein; HDL: high-density lipoprotein; SD: standard deviation; \*: standard error; NSPT: non-surgical periodontal treatment; SG SRP: supragingival scaling and root planning; tx: treatment.

### 2.4.1. Baseline vs. 3-Month Follow-Up

After a 3 month observation period data from five studies [10,12,13,15,16] were included in the meta-analysis (Figure 3). A total of 235 participants in four studies [10,12,13,15] were analysed for changes in their total cholesterol levels and there was a statistically significant differences in favour of the intervention group (*p* = 0.001, mean difference −0.47 mmol/L (95% CI, −0.75 mmol/L to −0.18 mmol/L)) with evidence of high heterogeneity (Chi<sup>2</sup> = 35.22, 3 df, *p* < 0.00001, I2 = 91%). A total of 330 patients in four studies [10,13,15,16] were analysed for changes in triglycerides, and there was a statistically significant difference in favour of the intervention treatment (*p* < 0.00001, mean difference −0.20 mmol/L (95% CI −0.24 mmol/L to −0.16 mmol/L, Chi<sup>2</sup> = 179.34, 3 df, *p* < 0.00001, I2 = 98%)), with evidence of high heterogeneity. A total of 330 patients in four studies [10,13,15,16] compared changes in LDL levels, and there was no significant difference between the intervention and the control treatment (*p* = 0.21, mean difference −0.02 mmol/L (95% CI −0.06 mmol/L to 0.01 mmol/L, Chi<sup>2</sup> = 16.64, 3 df, *p* = 0.0008, I2 = 82%)). A total of 392 patients in five studies [10,12,13,15,16] compared changes in HDL levels, and there was a statistically significant difference in favour of the control treatment (*p* < 0.00001, mean difference 0.06 mmol/L (95% CI 0.03 mmol/L to 0.08 mmol/L, Chi<sup>2</sup> = 37.06, 4 df, *p* < 0.00001, I2 = 89%)), with evidence of high heterogeneity.

**Figure 3.** Forest plots depicting the changes of (**a**) total cholesterol, (**b**) triglycerides, (**c**) LDL, and (**d**) HDL (all in mmol/L) between the intervention and control groups at baseline and the 3-month follow-up.

### 2.4.2. Baseline vs. 6-Month Follow-Up

After 6 months, three studies [10,11,14] were included in a meta-analysis of total cholesterol, triglycerides, LDL and HDL. There were no statistically significant differences found for any lipid levels (Figure 4).

**Figure 4.** Forest plots depicting the changes of (**a**) total cholesterol, (**b**) triglycerides, (**c**) LDL, and (**d**) HDL (all in mmol/L) between the intervention and control groups at baseline and the 6-month follow-up.

### *2.5. Periodontal Outcomes*

The periodontal parameters at baseline, 3 months, and 6 months are outlined in Table 3. At baseline, four studies [10,13,15,16] reported a mean periodontal probing depth of 2.93 mm for the intervention groups, compared to 2.82 mm in the control groups. Three months after therapy a mean PD of 2.30 mm was reported in the intervention groups (PD reduction of 0.63 mm), compared to 2.81 mm in the control groups (PD reduction of 0.1 mm). For the comparison between baseline vs. 6 months, three studies [10,11,14] reported a mean baseline PD of 3.46 mm in the intervention group and of 3.99 mm in the control group. After 6 months, a mean PD of 2.63 mm in the intervention group (PD reduction 0.83 mm) and a mean PD of 3.14 mm in the control groups (PD reduction 0.18 mm) was reported.

Two studies [10,13] reported changes in bleeding on probing (BOP) between baseline and 3-month follow-up. For the intervention group a mean BOP of 43.4% was calculated at baseline and of 18.0% at 3-month follow-up. For the control group the mean BOP at baseline was 42.2%, compared to 40.2% at 3-month follow-up. Three studies [10,11,14] reported BOP values for baseline and 6-month follow-up. For the intervention group a mean BOP of 56.5% was calculated at baseline and of 27.0% at the 6-month follow-up assessment. For the control group, the mean BOP at baseline was 56.3%, compared to 47.8% at 6-month follow-up.


**Table 3.** Periodontal parameters at baseline, and 3 and 6 months.

62

standard error; BOP: bleeding on probing (%).
