Read takeaways from the webinar by Dr. Tihana Divnić-Resnik

What are the most common myths and truths about chemical plaque control? Read the takeaways from the webinar by periodontist Dr. Tihana Divnić-Resnik. 

Mouth rinses are commonly used as a substantial part of effective chemical plaque control. Curaden Academy’s webinar led by the expert in periodontics, Dr. Tihana Divnic-Resnik from the University of Sydney, covers various topics connected with non-mechanical plaque control and brings much useful information for the daily practice of dental professionals. Here are some of the key points raised in the webinar, and answers to questions posed by the webinar participants.

The webinar Shaping the future of oral prevention – myths and truths about chemical plaque control focused on five main topics:

• Evidence-based update on commonly-used oral antiseptics in daily dental practice 
• Mechanism of action
• Indications for use and adverse effects
• Controversies and open questions related to oral antiseptics
• Exploring new directions in designing a ‘rinse’ of the new age

Why chemical plaque control is needed

In biofilms, microorganisms are more than 1,000 times more resistant to chemicals than in planktonic form. That is the reason it is essential to disrupt biofilms regularly. The best way to do this is with mechanical cleaning of teeth and interdental spaces, but there are many cases that require an alternative. For example, after complicated surgeries or in patients with necrotising periodontal diseases, such as necrotising gingivitis and/or necrotising periodontitis, that are not able to brush their teeth due to extensive bleeding and pain. Here is where chemical ways of fighting plaque come into play.

Dr. Divnić-Resnik describes the best possible features of a mouth rinse: “An ideal antiseptic should not be toxic, with pleasant taste, should have satisfactory antimicrobial potential, high substantivity, should not cause adverse effects, it should not interact with toothpaste components and also should not promote bacterial resistance.”

“As mechanical plaque control must be tailored to the patient’s needs, the choice of chemical plaque control must follow the same rules and it is our task to recommend the proper mouth rinse according to the indications,” says the periodontics expert.

She presents a classification of substances for plaque control according to their purpose of use. There are three groups of chemicals for plaque control:

• Those that can be used instead of mechanical plaque control – chlorhexidine (CHX), delmopinol, acidified sodium chlorate
• Those that can be used as an adjunct to mechanical plaque control – essential oils (EO), cetylpyridinium chloride (CPC), triclosan
• Those that can be used more as a cosmetic agent due to their low to moderate effect on plaque accumulation –oxygenating agents (hydrogen peroxide), povidone-iodine, hexetidine, natural products

Chlorhexidine – when it is recommended and how it should be used?

As we all know, chlorhexidine is one of the most widely studied and used antiseptics in dental practice, and also generally in medicine.

In dentistry, CHX is mainly used in the prevention and treatment of gingivitis and periodontitis. It is also used to treat mild infections caused by candida spp. such as denture induced stomatitis. In addition, there is increasing body of evidence that it can be effective in prevention and treatment of peri-implant diseases.

In terms of plaque control, chlorhexidine has the ability to prevent formation of a newly acquired pellicle, to prevent bacteria from binding to the tooth surface. It can also disrupt the structure of existing bacterial plaque to some extent, however its ability to penetrate mature biofilm is low and therefore mechanical biofilm/calculus removal is of paramount importance when CHX is recommended as adjunct to regular mechanical oral hygiene.

Dr. Tihana Divnić-Resnik provides some useful findings how CHX works in practice: “After a single rinse with CHX, at least 30% binds quickly and remains on the oral mucosa and is gradually released over 8-12 hours. This means that if the patient rinses with CHX mouthwash twice a day, it provides 24h bacterial suppression. Concentrations depend on the goal of the treatment. Generally, optimal CHX dosage for both plaque inhibition and reduction of gingival inflammation is 20mg CHX twice a day. This means roughly 10ml of 0.2% CHX mouthwash or 15ml of 0.12% CHX mouthwash.”

The duration of the treatment varies – usually between 2 to 4 weeks, depending on severity of the oral problems, and can go up to 6 weeks in the more complex cases. “CHX may be used as monotherapy for short time in cases after surgical intervention or during acute phase of some oral conditions or infections. Commonly, it is used as an adjunct to mechanical plaque control. In certain cases it can be used as adjunct to other medications such as antifungal therapy. It has also shown benefits in prevention and treatment of simple cases of oral halitosis.

To prevent patients’ compliance issues and avoid any potential problems, it is important to consider and explain CHX adverse effects. “The main adverse effect of CHX is discolouration. Reducing CHX concentration and combining it with other potent agents, such as Citrox, may be a new strategy in minimising its staining potential while preserving its anti-plaque and anti-inflammatory properties. In addition, this combination is alcohol-free and may also play a role in prevention of microbial resistance to CHX which has become a hot topic in the recent medical research.”

Dr. Divnić-Resnik adds one note, that should be considered before prescribing a CHX mouth rinse to a patient: “Mechanical removal of biofilm and calculus is a prerequisite for increased efficacy of CHX, and at the same time, by these actions we can reduce its local adverse effects, especially its potential to cause discoloration.”

Three most common questions on the impact of chlorhexidine on the healing process

In the Q&A session of the webinar, dentists from all over the world raised various questions. We have selected some of those most relevant to the impact of CHX on the healing process, and Dr. Tihana Divnić-Resnik’s responses.

1. Does chlorhexidine slow down bone healing in a dry socket?

“I couldn’t identify any studies that prove that CHX can have a negative impact on the wound healing. In contrast, there are several most recent studies and systemic literature reviews conducted in 2012, 2017 and 2018 that tested the efficacy of CHX rinse or gel in preventing dry sockets in patients who are smokers and that have a history of dry socketsespecially after third molar extraction. Results showed that CHX actually facilitated healing and prevented infection and alveolar osteitis or dry socket. To the best of my knowledge, clinically, it wouldn’t hamper any phases of the healingprocess.”

2. For chronic, acute periodontal disease, should we prescribe 2 or 4 weeks of CHX treatment?

“We don’t have any strict guidelines about that. Usually we have scientific evidence on one side and clinical experience on the other. For minor cases and gingivitis, 2 weeks are enough. If you have more complicated cases or patients after periodontal or muco-gingival surgery, while the patient has a sensitive and swollen area, they preferably shouldn’t do anything that might cause further irritation in that area. In such cases, you can recommend it for 4 weeks and extend it up to 6 weeks. Besides this, alcohol-free lower concentrations of CHX used for a short time (up to a week) may be beneficial in patients with oral ulcers, erythema multiforme (Steven-Johnson syndrome), ulcerative lichen planus and similar oral conditions. In mentioned cases, higher concentrations can be unpleasant for the patient. For pregnant and/or breastfeeding women it is important to consult with their dentist prior to choosing any antiseptic mouth rinse and it is important to use a rinse without alcohol.”

3. Can you use CHX in necrotizing periodontal diseases?

“Yes, especially during the acute phase when the patient is taking medication (eg. metronidazole) and can’t brush their teeth because gingiva is very painful due to the active necrotic process as well as bleeding. Bleeding can be very extensive and even spontaneous. For the first 72 hours or so of the acute phase we can prescribe CHX to reduce the number of bacteria, and it is the only means of plaque control that the patient can do. Later on, when we assess the patient again and confirm that acute phase is in remission, we should reinforce mechanical plaque control.”