How to cite this article: Orozco J, Contreras L, López J. Salivary pH as an improvement parameter in patients with periodontitis: A pilot

study. Ciencia e Innovación en Salud. 2020. e85: 277-285. DOI 10.17081/innosa.87

Salivary pH as an improvement parameter in patients with periodontitis: A

pilot study

El pH salival como parámetro de mejora en pacientes con periodontitis: Un

estudio piloto

Jennifer Orozco Páez

, Leonora Contreras de la Rosa

y Josefyn López Banda

Corporación Universitaria Rafael Núñez; Cartagena, Colombia

* Dirigir correspondencia a: jennifer.orozco@curnvirtual.edu.co

ABSTRACT

Background: the pH is a chemical parameter of saliva widely studied at present, its normal range is between

6.5 and 7.2. Its alteration has been linked to different oral pathologies, such as periodontal diseases. The

purpose of this study was to identify the usefulness of salivary pH measurement as an indicator of improvement

in patients with periodontitis and to estimate its possible relationship with the biofilm index and the number of

periodontal pockets. Methods: A descriptive-comparative pilot study was conducted on forty adult patients; one

group was conformed by twenty patients with gingivitis and the second one by twenty patients with chronic

periodontitis. In both groups was determined the biofilm index, was performed periodontal probing and a

salivary sample was taken for salivary pH measurement, before and after periodontal treatment. Results: the

results showed that of 20 periodontitis patients evaluated, 6 (30%) had an initial alkaline pH greater than 7,6

and a moderate positive relationship with the biofilm index was observed (r=0.5277). After treatment, 15(75%)

periodontitis patients and 14 (70%) gingivitis patients presented a decrease in this parameter. Conclusions:

there is a variation in the salivary pH after periodontal treatment tending to its restoration, this probably occurs

in response to periodontal tissue repair, therefore, pH is a salivary parameter that has potential for monitoring

patients with periodontal disease.

Article History

Received: 13 06 20

Accepted: 11 08 20

Published: 25 08 20

Keywords: Periodontal Diseases; Periodontitis; Hydrogen-Ion Concentration; Saliva

I. INTRODUCTION

Periodontal disease (PD) comprises a set of diseases that affect the

periodontium; these are diverse, but gingivitis and periodontitis are the ones

that most frequently affect the adult population and which the dentist faces

in his routine consultation. Specifically, periodontitis presents as an

inflammation that affect the supporting tissues of the tooth, causing the

destruction of the gingival connective tissue and alveolar bone, resulting in

the formation of periodontal pockets. Due to its high prevalence, it has

become a topic of public health interest worldwide (1, 2).

DOI 10.17081/innosa.87

Contreras

et al.

278 
 
Due to this negative impact that PD has generated on the oral health of different populations, this 
pathology has been studied for many years. This has allowed that at present, the diagnosis and 
evolution of PD is not only based on clinical and radiographic methods, but also it has become in 
an  open  space  for  the  assessment  of  countless  biochemical  markers,  such  as,  proteins, 
enzymes, immunity and inflammatory mediators that reflect the periodontal state of the patient, 
before and after being subjected to periodontal therapy (4-6). In the case of periodontitis, where 
the  destruction  of  periodontal  tissues  is  progressive,  it  has  been  possible  to  establish 
relationships between the patient's periodontal condition and variations of salivary parameters 
(7-9). 
In addition to the markers, a biochemical indicator that is related to the pathophysiology of PD is 
salivary pH; this parameter is defined as the degree of acidity or alkalinity of an aqueous solution. 
Since during the periodontal disease the patient experiences changes in the periodontium, such 
as  inflammation,  bleeding,  bone  loss  among  others,  it  is  feasible  to  believe  this  pathology 
modifies the properties of saliva including its pH (10-12). Thanks to the complex composition and 
multitude of organic components present in saliva, this is a powerful tool for the diagnosis and 
monitoring  of  oral  diseases;  dental  caries,  Periodontal  diseases,  oral  cancer,  Sjögren’s 
syndrome, are some examples (13). Regarding its buffer function, it is responsible for maintaining 
a neutral pH (6.5 to 7.2) in oral cavity, however, the salivary pH has been found modified under 
pathological conditions (14-16).  
From  these  considerations,  a  hypothesis  arises,  the  salivary  pH  is  altered  in  patients  with 
periodontitis  and  returns  to  its  normal  ranges  after  periodontal  treatment.  In  this  way,  the 
measurement of salivary pH can helps as a complementary parameter for the diagnosis and 
periodontal health monitoring in patients with periodontal disease.  
The aim of this investigation was to identify the usefulness of salivary pH measurement as an 
indicator of improvement in patients with periodontitis and to estimate its possible relationship 
with the biofilm index and the number of periodontal pockets. 
 
II. METHODS  
2.1. Design, population and sample: a comparative - descriptive pilot study was designed. 
The study population corresponded to patients who attended the dental clinic of Corporación 
Universitaria Rafael Núñez, Cartagena, Colombia. Forty systematically healthy patients were 
selected by convenience sampling taking into the inclusion criteria and were divided into two 
groups as follows: 
-Group A: Comprised of twenty chronic periodontitis subjects with periodontal pockets ≥4 mm, 
presence of biofilm, bleeding or not from periodontal probing, with loss of clinical insertion from 
1mm periodontitis (Classification of Periodontal Conditions and Diseases 1999) and indication 
for non-surgical periodontal therapy. 
-Group  B:  comprised  of  twenty  gingivitis  subjects  with  presence  of  bleeding  on  probing 
associated  with  biofilm,  with  absence  of  peridontal  pocket  and  absence  of  loss  of  clinical 
insertion (Classification of Periodontal Conditions and Diseases 1999) (17). 

279

To avoid the entry of sample units that alter the study results, were excluded smoking patients,

patients in pharmacological treatments, with dental abscesses or other type of oral pathology

and patients with salivary flow disorders or pathology in salivary glands. For data collection, the

following methodological steps were developed.

2.2. Clinical history record: Before writing the medical history, the purpose of the study were

explained verbally to each patient, the patient confirmed their voluntary participation in the study

by signing an informed consent. Subsequently, two previously calibrated examiners performed

anamnesis, clinical stomatological examination, evaluation of the biofilm index according to

O'Leary, periodontal probing with a North Carolina periodontal probe and the periodontogram

in which the presence of periodontal pockets, the level of clinical insertion and the presence of

bleeding were recorded. The patients were classified according to their periodontal diagnosis

based on the Classification of Periodontal Conditions and Diseases of 1999, as explained

above.

2.3. Sampling of saliva: Samples were taken at two different times, as follows:

Sample # 1: first date

Sample # 2: thirty days after periodontal treatment

The sample of unstimulated saliva was collected in a labeled clean tube. The recommendations

given to the patient for sampling were:

- do not ingest liquid or solid food at least two hours before the procedure,

- do not brush your teeth at least 3 hours before taking the sample and

- not having consumed medications in the days prior to taking the sample.

Before donating the sample, each patient signed an informed consent for sampling, through

which they voluntarily gave in and authorized the study investigators to process and obtain

results from their saliva samples.

2.4. Salivary pH measurement: Once the sample was obtained, the salivary pH was

immediately measured using a portable digital pH meter (Ref. 315i WTW brand). In this

process, the calibration of the equipment was started following the recommendations of the

manual, then the electrode was submerged in the depth of the sample, the quantitative pH data

was recorded in a data record table.

After the first sampling, each patient was treated by his own operator, receiving supervision

from a periodontist during the process. The treatment carried out consisted of non-surgical

periodontal therapy, which included teaching in oral health, scaling and root planning (two

dates) in patients with periodontitis or prophylaxis in gingivitis patients. Thirty days after the

periodontal treatment, patients were again cited for the second sampling and the second biofilm

index measurement and periodontal probing.

2.5. Analysis and interpretation of data: the data were tabulated in an Excel® 2016 table,

then the data were exported to statistical software SPSS version 2.0 (IBM Corp. IBM SPSS

statistics for Windows version 2.0, Armonk, NY, USA) for statistical analysis. First, a descriptive

analysis was performed in which measures of central tendency and dispersion (mean ±

standard deviation) were calculated for the quantitative variables. To perform intragroup

comparisons (before and after treatment) a Student t-test for related samples was applied. For

intergroup comparisons a Student t-test for independent samples was applied, assuming

280

significance when p <0.05. The Pearson correlation coefficient was used to relate the salivary

pH to biofilm index and number of periodontal pockets.

2.6. Ethical aspects: The study complied with the ethical aspects and international

recommendations of the Declaration of Helsinki of the World Medical Association and of the

health research norms of the Ministry of Health of Colombia. According to resolution 008430

of 1993 of Ministry of Health of Colombia, this is an investigation with minimal risk (chapter 1,

item 11, subsection b).

III. RESULTADOS

From the forty patients who participated in the study, 30% were male and 70% female.

Regarding age, 40% of the population was in an age range greater than 35 years.

3.1. Salivary pH measurement

The group A, presented an initial average pH of 7.42 ± 0.23, which decreased to 7.25 ± 0.23

after periodontal treatment. When comparing the means, a statistically significant difference

was found (p = 0.0012) (Table 1). Regarding the individual behavior of salivary pH in each patient, it

was observed that of the 20 patients evaluated in this group, 6 (30%) had an initial pH greater than 7.6

and after treatment 15 (75%) experienced decrease (Figure 1, A).

Table 1. Comparison of salivary pH before and after periodontal therapy in each

study group and intergroup comparison.

Gingivitis patients

(n=20)

Periodontitis patients

(n=20)

p-value

(Mean±SD)

95% CI

(Mean±SD)

95% CI

Salivary pH

Before

treatment

7.01 ± 0.25

6.89 - 7.13

7.42 ± 0.23

7.31 - 7.53

0.000*

After

treatment

6.93 ± 0.12

6.87 - 6.99

7.25 ± 0.23

7.14 - 7.36

0.000*

p-value

0.1027**

0.0012**

*Independent Samples t-test, (p<0.05 – Statistically Significant)

** Related samples t-test (p<0.05 – Statistically Significant)

281

Figure 1. Individual behavior of salivary pH before and after periodontal therapy. Periodontitis

patients (A), Gingivitis patients (B).

In the group B, the average initial salivary pH was 7.01 ± 0.25, after the treatment was reduced

to 6.93 ± 0.12, no statistically significant difference was found between the two moments (p =

0.1027) (Table 1). Of the 20 patients evaluated in this group, 14 (70%) experienced a decrease

in salivary pH, after receiving therapy, while 6 (30%) experienced an increase (Figure 1, B),

despite this, the salivary pH of this group always stayed within the normal range. When

comparing salivary pH between the two study groups, the values for periodontitis patients were

higher compared to the salivary pH of patients with gingivitis at the two times evaluated, this

difference was statistically significant (p = 0.000) (Table 1).

3.2. Biofilm Index Measurement

Before treatment, group A patients had an average biofilm index of 65.80% ± 14.05 which after

treatment was reduced to 50.25% ± 14.55. On the other hand, the group B had an average

index of 68.25% ± 17.18 before treatment and was reduced to 39.25% ± 13.80 after being

treated (Table 2).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Before treatment

7,28 7,31 7,25 7,28 7,61 7,13 7,37 7,75 7,47 7,61 7,43 7,08 7,83 7,7 7,3 7,31 7,25 7,43 7,82 7,23

After treatment

7,13 7,24 7,12 7,19 7,29 7,04 7,43 7,79 7,15 7,41 7,09 6,93 7,12 7,72 7,31 7,43 6,92 7,32 7,35 7,11

6,4

6,6

6,8

7,2

7,4

7,6

7,8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Before treatment

7,14 7,27 7,31 7,2 7,09 6,97 7,26 7,19 6,98 7,11 6,97 6,55 6,9 6,94 6,85 7,28 6,46 6,99 7,14 6,59

After treatment

6,91 7,05 6,84 6,73 6,92 6,91 7,11 7,02 6,81 7,02 6,86 6,66 7,06 6,91 6,99 7,09 6,85 7,03 7,03 6,81

6,2

6,4

6,6

6,8

7,2

7,4

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Table 2. Intragroup and intergroup comparison of biofilm index mean and

intragroup comparison of number of periodontal pockets mean.

Study group

O’Leary Index

(mean ± SD)

N° periodontal Pockets

(mean ± SD)

Before

treatment

After treatment

p-value*

Before

treatment

After

treatment

value*

Gingivitis

(n=20)

68.25 ± 17.18

29.25 ± 13.80

0.000

Periodontitis

(n=20)

65.8 ± 14.05

50.25 ± 14.54

0.001

5.3 ± 2.28

4.3 ± 2.11

0.000

p-value**

0.695

0,046

* Wilcoxon test ** Mann-Whitney test (p<0.05 – Statistically Significant)

In order to determine if there is a relationship between the biofilm index and salivary pH, the

Pearson correlation test was applied. For none of the two groups there was a correlation

between these variables before treatment. In contrast, the post-treatment analysis showed a

moderate positive correlation (Pearson r=0.5277) between these two variables in patients with

periodontitis (Figure 2).

Figure 2. Correlation between salivary pH and biofilm index of patients with periodontitis after

periodontal treatment. *Pearson correlation coefficient.

3.3. Determination of periodontal pockets

An average of 5.3 pockets per patient was found in the periodontitis group. In 16 (75%) of them,

periodontal pockets disappeared after therapy (Table 2). Because this result was an indicator

of improvement, the number of pockets was related to salivary pH at two times, a direct

relationship was observed before (r=0.29) and after (r=0.27), the level of relationship was low,

283

however, it lets us know that the variables are not independent, but the number of pockets may

be related to the participant's salivary pH.

IV. DISCUSSION

Within its protective role, saliva is responsible for creating the appropriate oral conditions for

the maintenance of the environmental balance, one of its mechanisms is maintaining the neutral

oral pH through the bicarbonate and phosphate buffer system (18). The salivary pH has been

studied due to its possible contribution to monitor or as a complement in the diagnosis of

different oral diseases (19).

The results of this research show that salivary pH is maintained within a neutral range in healthy

patients/mild gingivitis, while in patients with periodontitis tends to alkalinity maintaining an

average pH of 7.42 ± 0.23, of this average, 30% of patients had a salivary pH higher than 7.6

before treatment and 75% experienced a decrease after periodontal therapy. Authors like

García S, et al (2008) (20) reported similar results, a salivary pH of 6.9 in healthy patients, while

patients with gingivitis and periodontitis had average values of 7.3 and 7.9 respectively. After

treatment, from 60 patients treated, 40 responded satisfactorily, observing a considerable

reduction in salivary pH. Likewise, these authors reported salivary pH increases as the

percentage of affected teeth increases. In this study, a low direct correlation was observed

between salivary pH and the number of periodontal pockets before and after treatment, these

results suggest that salivary pH is made alkaline as the severity of periodontal disease

increases.

Baliga S, et al (2013) (8), report an average salivary pH of 6.85 ± 0.11 in patients with

periodontitis, disagreeing with this study that showed a pH with an alkalinity tendency for these

patients. These authors expose that a salivary pH above 7.0 generally indicates alkalinity,

excessive alkalinity can cause anaerobic conditions, in this case the biofilm take calcium

compounds from the oral environment and use minerals to protect themselves from high pH. A

high pH above 7.6 promotes the formation of crystals of the biofilm that favors the development

of periodontal disease, while a low pH promotes demineralization of the tooth structure and

favors the growth and metabolism of acidogenic and acid-tolerating bacteria, whilst at the same

time inhibiting many of the beneficial resident species (21).

Although the salivary pH range presented by patients with periodontitis in this study was not at

extreme alkalinity values, this could be explained because the participants' periodontal disease

was not severe, however, the patients presented high biofilm rates. The fact that salivary pH

decreased after periodontal therapy, trying to restore itself, reflects the role of the biofilm in the

variation of the pH and especially considering that a moderate direct correlation was found

between pH and the biofilm index in patients with periodontitis after treatment.

In a similar study, Patel RM et al (2016) (11) report that patients with chronic generalized

periodontitis with periodontal pockets larger than 4 mm and with loss of clinical insertion have

oral hygiene rates, gingival index and plaque index significantly higher than those found in

periodontally healthy patients with gingivitis. Likewise, they report an average salivary pH of

11.65 ± 2.26, extremely alkaline for this group of patients. Therefore, they suggested that as

the severity of periodontitis increases, the values of oral health indices also gradually increase

284

and salivary parameters are altered, including salivary calcium, phosphorus, alkaline

phosphatase and pH.

Regarding to the number of periodontal pockets, a significant improvement was observed after

periodontal therapy when a decrease in the number was found. Taking into account that

salivary pH was restored in patients with a decrease in the number of pockets, finding a positive

direct relationship, although low, it is possible to consider salivary pH as a possible indicator of

improvement in patients undergoing treatment. However, it must be confirmed with new studies

with a larger sample size and a more extensive follow-up in time.

The main limitation of this study was the small sample size, however, from the results, pertinent

conclusions were derived that allowed observing the behavior and relationship of salivary pH

with clinical oral health indices that give rise to the formulation of new ideas research.

V. CONCLUSIONS

The salivary pH of patients with periodontitis is slightly alkaline and varies after periodontal

therapy tending to restore to normal levels, this probably occurs in response to periodontal

tissue repair, likewise, the pH varies keeping a direct relationship with the biofilm index and with

the number of periodontal pockets. Taking these results into account, it is possible to consider

that pH is a salivary parameter that has potential for monitoring patients with periodontal

disease.

Author Contributions: "Conceptualization, J.OP.; methodology, J.OP.; Validation, J.OP.;

Formal analysis, J.OP and J.LB.; Research, J.OP., J.LB y L.CR.; data healing, J.LB. L.CR.;

Writing: preparation of original draft, J.OP. L.CR.; writing: review and editing, J.OP., L.CR and

J.LB; viewing, J.LB.; supervision, J.OP.; project management, J.OP”. All authors have read and

accepted the published version of the manuscript. "Yes”

Acknowledgements: The authors would like to express our sincere gratitude to Dr. Roquelina

Pianeta Alviz for her support and for sharing her knowledge which was important to carry out

this work.

Conflicts of interest: the authors declare that they have no conflicts of interest

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