Mechanical plaque control

Introduction to mechanical plaque control

The mechanical plaque control by humans is as old as the history of mankind. Dental literature is full of reports stressing the importance of maintaining oral hygiene. It has been known for centuries that a good oral hygiene is the primary requirement for healthy teeth and periodontium. However, the scientific literature came into the picture later, when various studies established an association between plaque and periodontal inflammation. In one of the initial studies, cause and effect relationship between supra-gingival plaque and gingivitis was demonstrated by Löe and his colleagues in 1965 ¹. In this experimental study, the plaque was allowed to accumulate, which resulted in the development of gingivitis within 21 days. When plaque control was initiated using brushing and flossing, gingivitis was reversed to clinical gingival health. Further investigations ^2-5 provided more evidence for this association and plaque control was established as a primary measure to prevent the development of periodontal diseases. Presently, these is a strong evidence in favor of the association between presence of local factors and periodontal disease progression and the re-establishment of periodontal health following the removal of these factors.

     Plaque control is defined as the removal of microbial plaque and food debris from the oral cavity ⁶. This can be accomplished either mechanically or chemically or a combination of the two procedures. In the present discussion, we shall discuss the self-performed mechanical plaque control methods.

Rationale for mechanical plaque control

The periodontal pathogens inhabiting periodontal pockets are primarily responsible for the inflammatory and destructive periodontal diseases. Various epidemiological studies have demonstrated a very strong correlation between the localization of dentogingival plaque and periodontal disease ^{7, 8}. The periodontal pathogens are present in a well-organized structure of dental plaque. Dental plaque formation starts with the formation of dental pellicle, which matures by incorporating various Gram-positive and Gram-negative bacteria. If plaque is not removed regularly, the micro-organisms and their products start damaging the periodontal tissue, thereby initiating host-bacterial interactions. These interactions lead to the ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

History of mechanical plaque control

Throughout the history of mankind, various cleansing aids have been used to remove deposits around the teeth. Primitive man used figure nails and splinters of wood to remove deposits in between the teeth. The first known toothpick which belongs to Sumerian civilization was made from gold and dates back to about 3000 B.C. The Chinese were amongst the first people to use the chewstick as a toothpick and toothbrush to clean the teeth and massage the gingival tissues. The Chinese designed gold and silver toilet sets which included stiletto-like toothpicks. Toothpicks were used by Greeks, Romans, and Hebrews also. The toothpicks used by the Romans were made up of bronze, gold or silver. Hippocrates (460 B.C.) recommended cleaning the teeth with a ball of wool soaked in honey. Toothbrushes during early civilization were made from various materials such as sponges, shredded ends of certain sticks and lint.

      Although, the exact origin of the toothbrush is not known, the earliest toothbrushes have been recorded from China, dating back to 1498. These toothbrushes were made up of bone or ivory handles with natural bristles attached perpendicular to the long axis of the handle. The mass production of toothbrushes started in Europe during late 18th and early 19th century and since then toothbrushes are one of the most commonly available items in all parts of the world. The first mechanical toothbrush was probably designed by Frederick Wilhelm Tornberg, a watchmaker in Stockholm in 1885 ¹³. The invention was a new design of a toothbrush which allowed easy cleaning of teeth on the inner side as on the other side. The new introductions in toothbrushes include the electric toothbrushes, ionic toothbrushes, chewable toothbrushes etc. (discussed later).

Classification of mechanical plaque control aids

In the present context, various means of oral hygiene measures are used to aim at the removal of plaque and other deposits. These mechanical plaque control measures can be classified as,

Toothbrushes:

• Manual toothbrush.
• Electric toothbrush.
• Ionic toothbrushes.
• Chewable toothbrush.
• Ecological toothbrushes.
• End-tuft brushes.
• Sulcabrushes.
• Beam toothbrush.

Interdental Aids:

• Dental floss.
• Triangular tooth picks.
• Interdental brushes.
• Yarn.
• Superfloss.
• Perio-Aid.

Aids for gingival stimulation:

• Rubber tip stimulator.
• Balsa wood wedge.

Tongue cleaners.

Others:

• Gauze strips.
• Oral irrigation device.

Aids for completely or partially edentulous patients:

• Denture and partial clasp brushes.
• Cleansing solutions.

     The mechanical plaque control aids are the backbone of plaque control. In the following sections, we shall discuss in detail these mechanical plaque removal aids, including their method of use and indications.

Toothbrushes

Manual toothbrushes:

The manual toothbrush is widely used as an oral hygiene aid and is often the sole means of plaque removal for many people. When performed correctly, for an adequate duration of time, manual brushing is highly effective for most patients.

Brief History:

Although the tooth brushing tools date back to 3500-3000 BC, when the Babylonians and the Egyptians made a brush by fraying the end of a twig, the Chinese are believed to be the inventors of the first natural bristle toothbrush in the 15th century. It was made from the bristles from pigs’ necks. The bristles were attached to a bone or bamboo handle. This toothbrush design was adopted by European people who modified it by using softer horsehairs or feathers as bristles.

     The design of a modern toothbrush can be attributed to William Addis of Clerkenwald, England around 1780. In fact, he was put in jail for inciting a riot. To while away the time and freshen up in the process, he designed a toothbrush by carving the handle of the toothbrush with cattle bone and the brush portion with swine bristles. He drilled holes in the handle and put the bristles in these holes and stabilized them with a wire. Addis started mass-producing his contraption after leaving prison and died in 1808 as a wealthy man. After he died, he left the business to his eldest son, also called William, and it stayed in family ownership until 1996. His company “Wisdom Toothbrushes” presently manufactures 70 million tooth-brushes per year in the UK.

     The first 3-row bristle brush was designed in 1844. During the 1900s, celluloid handles gradually replaced bone handles in toothbrushes. The first American to patent a toothbrush was H N Wadsworth, (patent number 18,653) on Nov. 7, 1857. Soon after the invention of nylon by DuPont laboratories in 1938, the bristles were replaced with this new material. The first nylon toothbrush was called Doctor West’s Miracle Tuft Toothbrush. By 1938, the truly modern toothbrushes came ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Design of toothbrush

The toothbrush is the fundamental tool for mechanical removal of plaque and other deposits. The requirements of a toothbrush are,

• A toothbrush should be durable so that it can be used by the patient for a long duration of time.
• The brush head should be small enough to be manipulated effectively, yet large enough to cover tooth surfaces.
• The bristles should be of an even length so that they can function simultaneously. Too long bristles will not be able to clean the tooth surfaces properly and too short bristles will fail to reach the interdental sites.
• The texture of the bristles should be smooth so that they do not injure the gingiva.
• It should be flexible and light-weight for easy manipulation.
• It should have strong bristles which are not too rigid.
• The toothbrush should be easily cleanable. The nylon bristles are more hygienic than the natural bristles.
• The toothbrush should be able to meet individual requirements.

     Toothbrushes vary in size, design, length, hardness, and arrangement of bristles. According to American Dental Association (ADA), the method and toothbrush choice depends on patient oral health, manual dexterity, personal preference, ability and their desire to learn and follow the prescribed procedures. The ADA specification 14 for toothbrush is as follows,

Length of brushing surface = 1-1.25 inches (25.4-31.8 mm)
Width of brushing surface = 5/16 – 3/8 inches (7.9-9.5 mm)
Rows of bristles = 2-4
Tufts per row = 5-12
Bristles per tuft = 80-86

     The bristles used to make the toothbrushes may be made up of natural bristles from hogs or artificial bristles primarily made of nylon. Presently, artificial bristles made up of nylon predominate in the market and have been shown to have superior properties. The tufts of the bristles are arranged in 3 to 4 rows on the brushing surface. The ends of the bristles are made round so that gingiva is not hurt during brushing. The diameter of the bristles ranges from 0.007 inches for soft brushes to 0.012 inches for medium brushes to 0.014 inches for hard brushes. Soft brushes are most commonly used. Use of hard brush and abrasive dentifrice may lead to cervical abrasion of the teeth and recession of gingiva. Bass recommended the use of soft nylon bristles with a diameter of 0.007 inches and a length of 0.406 inches with rounded ends arranged in 3 rows of tufts, six evenly ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

     The stiffness of the bristles depends on the diameter and length of the bristle filament and its elasticity. It also depends on whether the brush is used dry or wet and if wet, the temperature of water. A soft toothbrush typically has around 1600 filaments with 0.008 inches diameter and approximately 11 mm length, arranged in around 40 tufts in three or four rows.

     Toothbrushes are available with different designs of handle, head and neck. The handle of the toothbrush may be straight or angled and thick or thin. Single or double angulation in the neck of the handle is provided so that the brush can reach the most distal surfaces of the posterior teeth. Toothbrushes recommended for most of the patients have a short head, soft or medium bristles with rounded ends arranged in three or four rows of tufts.

Electric toothbrushes

The electric toothbrushes provide a brush head, which is capable of a variety of movements driven by a power source. The first electric toothbrush was designed to mimic the back and forth motion which is commonly used in manual tooth brushing method. Presently, many powered toothbrushes use circular or elliptical motion and still others use a combination of motions.

      After the introduction of powered toothbrushes, their comparison was done with manual toothbrushes in determining the efficacy of plaque/debris removal. Early reports suggested that both manual and electric toothbrushes were equally effective in removing plaque ¹⁵. Because of lack of superiority over manual toothbrushes and problems associated with mechanical breakdown, the electrical toothbrushes were no more preferred over manual toothbrushes and during the late 1960’s they gradually disappeared from the market. However, they were still recommended for handicapped patients and persons with reduced manual dexterity.

       It was recommended in the World Workshop in Periodontics, 1966 that persons who are not highly motivated towards maintaining good oral hygiene or those who are not able to master a suitable brushing technique are the candidates suitable for the use of electrical tooth-brushes ¹⁶. Since then a lot of modifications have been done in ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

     The initial powered toothbrushes were not so user-friendly because of their cumbersome size, power source unreliability, and a lack of concurrence regarding effective-ness. After extensive work on designing a powered toothbrush, Oral-B (Procter & Gamble Company, Cincinnati, OH, USA) came up with “D-1”, the first mass-produced power toothbrush. The brush was designed to perform side to side motion with a manual-like brush head. Following the introduction of D-1, electric brushes with rotary or circular movements (e.g., Rotadent® [Zila, Fort Collins, CO, USA]) and head tufts rotating in a counter-rotational fashion (e.g., Interplak® [Conair, East Winslow, NJ, USA]) were introduced. Another major development in powered tooth-brushes was the introduction of Oral-B Plaque Remover ‘D5’ in 1991. The brush was equipped with the prophylaxis-inspired oscillating-rotating mode of action 18. The brush had a cup-shaped head which oscillated at 5600 oscillations per minute. This was the first powered toothbrush which was clinically proven to clean the teeth better than a manual toothbrush ¹⁹.

     The electric toothbrushes work by performing oscillating or rotatory action of bristles which is driven by a motor. Most of the presently available powered toothbrushes are equipped with a timer and pressure sensors which improve the efficacy of brushing. The electric toothbrushes can be divided into three classes according to the speed of bristle movement as,

• Standard power toothbrushes.
• Sonic toothbrushes.
• Ultrasonic toothbrushes.

    Technically speaking, every electric toothbrush is a power toothbrush. It can be classified as a sonic toothbrush when its frequency of rotation is 20 Hz to 20,000 Hz or ultrasonic when it is more than that. Certain toothbrushes available in the market such as Megasonex and the Ultreo, have both sonic and ultrasonic movements. Sonic tooth-brushes generated sonic waves which create high-speed scrubbing strokes that can remove plaque from the subgingival and interdental areas. They may also create the cavitational effect, fluid streaming, and acoustic vibrations which may cause hydrodynamic stresses that also aid in dislodging microbial plaque.

     The ultrasonic toothbrushes have a piezoelectric ultra-sonic emitter (transducer) embedded in the brush head. The transducer undergoes dimensional changes when connected to the power supply, thus producing ultrasonic waves. When these waves are transmitted to the bristles, they vibrate with a microscopic amplitude which does not provide any tactile feedback to the user. The dentifrice is used to conduct these ultrasonic waves to the teeth and gingiva. These ultrasonic waves ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Ionic toothbrushes:

The concept, based on which ionic toothbrushes work has been utilized in dentistry in the form of iontophoresis, electrophoresis, and electrolyzing for years. Ionic brushes work on the principle of changing the surface charge of the tooth to repel plaque even from inaccessible areas of teeth. Another mechanism by which they remove plaque is by inhibiting coupling between the pellicle and bacteria, mediated by calcium bridges. Bonding between the pellicles and bacteria is mediated by Ca²⁺ ion bridge formation. The lithium battery in the toothbrush supplies anions which inhibit the bonding between the bacteria and Ca²⁺ ions, thus preventing the bacteria from adsorbing to the pellicles. The plaque removal is enhanced by both ionic exchanges, along with the normal mechanical action of the bristles on the tooth surface.

Chewable toothbrush:

These are miniature plastic molded toothbrushes which can be used when no water is available, commonly during traveling. They are most commonly available from bathroom vending machines and are available in different flavors. After using they should be disposed off. Some chewable brushes have a breakable toothpaste plastic ball on the bristles which again can be used without water.

Ecological toothbrushes:

The plastic which is used to make traditional toothbrushes is a small source of environmental pollution. To reduce this pollution, some manufacturers ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

End-tuft brushes:

The end-tuft brush is a small round brush composed of a head with seven tufts of tightly packed soft nylon bristles. They are trimmed in such a way that the bristles in the center can reach deeper into small spaces. These brushes are primarily used to clean areas such as posterior surfaces of last molars, orthodontic braces and tooth surfaces next to missing teeth. These brushes are also useful in cleaning bridges, dental implants, and other fixed appliances.

Sulcabrushes:

Sulcabrushes are specifically designed to clean the teeth along the gingival margin. Its bristles are trimmed in such a way that they closely adapt to the gingival margin. These are used to clean difficult to reach areas such as last molars, interdental areas in between crowded teeth, bridges, and fixed orthodontic appliances.

Beam toothbrush:

In this toothbrush, a sensor is attached to the brush to record and map brushing behavior of the patient. It was launched in 2010 and its advanced version came in Feb 2012 from Beam technologies. This brush can record the brushing data up to three weeks and can upload this data on an android mobile wirelessly. This data can be sent to the dentist so that it can be analyzed and an appropriate brushing technique can be demonstrated to the patients.

Interdental Aids

Before we discuss in detail the interdental aids, let’s first discuss the types of the embrasure. As already discussed in “Art of history taking in periodontics”, Nordland and Tarnow have given the classification of interdental papillary height as follows,

Normal: The interdental papilla occupies the entire embrasure space apical to the interdental contact point / area.

Class I: The tip of the interdental papilla is located between the interdental contact point and the level of the CEJ on the proximal surface of the tooth.

Class II: The tip of the interdental papilla is located at or apical to the level of the CEJ on the proximal surface of the tooth but coronal to the level of the CEJ mid-buccally.

Class III: The tip of the interdental papilla is located at or apical to the level of CEJ mid-buccally.

Dental Floss:

Dental floss is a cord of thin filament used to remove food debris and plaque from the interdental areas where bristles of the toothbrush cannot reach. It is one of the most commonly recommended oral hygiene aids by the health professionals. However, it has been observed that client ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Historical aspect:

Anthropologists have found evidence that dental floss was used by prehistoric humans. The teeth recovered have been shown to have groove marks which are characteristics of using dental floss like material. It was Dr. Levi Spear Parmly, who is credited as the inventor of modern dental floss in early 1800’s. He advised his patients to floss between their teeth using a silk thread. But, this new concept of cleaning the teeth was not very well accepted by patients. In 1882 a company called the Codman and Shurtleft Company, based in Randolph, Massachusetts started mass production of dental floss. In 1898, New Jersey based Johnson & Johnson secured ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Types of dental floss:

There are various types of dental floss available currently which include,

• Waxed and unwaxed floss.
• Teflon floss.
• Thread floss.
• Flavored and unflavored floss.
• Tape floss (also known as ‘dental tape’).

Waxed and unwaxed floss:

As the name indicates, waxed floss is coated with wax and is used in closely spaced teeth because it can easily slide between contacts. The waxed flosses are available with various flavors, which are preferred by many patients. The example of waxed dental floss is Oral-B waxed dental floss. On the other hand, unwaxed floss can be routinely used to clean the interdental areas. However, it is not as sturdy as waxed floss and is difficult to pass through the closely spaced teeth. The unwaxed floss typically has no flavor. Many patients find unwaxed floss easy to grip between the fingers.

Teflon floss:

This floss is made up of teflon, which makes it easy to slide between the teeth. Teflon is shred-resistant material and is stronger and more durable than many other types of floss. It does not usually stick in between the teeth, but if it does, it comes out easily. An example of this type of floss is Crest ‘Glide’.

Thread floss:

This is made from nylon and works in the same way as any other type of floss.

Flavored and unflavored floss:

Many dental flosses are available in different flavors such as mint or cinnamon. Many patients find them more pleasant to use as they leave a nice, clean taste in the mouth. Dental floss coated with fluoride is also available which may protect teeth against decay. As the name indicates, unflavored floss does not contain any flavor.

Tape floss (also known as ‘dental tape’):

The dental tape has a wider and flatter design as compared to conventional floss and is recommended for those individuals who have a larger area of the tooth surface to clean ²². This floss is suitable for patients new to flossing and has an advantage of not breaking or fraying. An example of this is Colgate Dental Tape.

Floss holder/ Floss pick:

It is made up of plastic body with two prongs extending from the body. A single piece of floss is attached at the end of two prongs which runs between them. Various companies have designed floss holders in the shape of “Y” or “F”. The body of the floss holder is broad which provides adequate grip for the operator. Most of the floss holder’s body tapers off into a pick. Floss holders are available in a variety of shapes, colors, and sizes for adults and children.

 

Triangular Tooth Picks:

The triangular-shaped wooden or plastic toothpicks are suitable for cleaning the interdental areas. Wooden sticks are made of balsa or birch wood and are more pliable than plastic sticks. Another advantage of wooden toothpicks is that they soften in the mouth after moistening with saliva. The soft and pliable toothpick is more effective in cleaning interdental areas and is less harmful to the gingiva As the shape of triangular toothpicks approximates the shape of the interdental embrasure, they can slide into the interdental areas. These can be used to clean Class II and Class III embrasures.

Interdental Brushes:

The interproximal or interdental brushes are made up of bristles which are mounted on the angled plastic handle. They are used to clean areas in between the teeth and between the wire of dental braces and the teeth. According to ISO 16409, they are color-coded from 1-7 according to the width of the brush. Interdental brushes are classified according to ISO standard 16409:2006. This classification also specifies the passage hole diameter which is the minimum diameter of the interdental hole which will allow its passage.

Yarn:

The yarn is rarely used these days to clean interdental areas. Its usage and functions are similar to that explained for dental floss. It is primarily used in interdental areas where the interdental papillae have receded and interdental embrasures are extremely large. Only synthetic yarn should be used because the wool fibers irritate the gingiva ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Superfloss:

It is a special kind of dental floss which is supplied in pre-cut segments. The ends of the floss are thin and stiff whereas the middle portion is tufted and fuzzy which helps in plaque removal. The superfloss can be inserted under the bridge or between orthodontic fixed appliances to clean plaque deposits.

Perio-Aid ®:

It is a toothpick holder which holds the toothpick at an appropriate angle, allowing difficult to reach interproximal spaces accessible for cleaning. The Perio-Aid ® is available in two different styles, Perio-Aid ® #2, which is double ended with an adjustable nut on each end that tightens the toothpick in place and Perio-Aid ® #3, which is single ended with an adjustable nut on one end to tighten the toothpick in place. The advantage of Perio-Aid ® #2 is that its each end provides a different angle ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Aids for gingival stimulation

Rubber tip stimulator:

It is primarily used for gingival stimulation, but can also be used to remove plaque biofilm by rubbing the tip against exposed surfaces. It is used by placing the rubber tip interdentally and in a coronal direction. Using an in-and-out motion, the tip is rubbed against the teeth and into contact areas.

Balsa Wood wedge:

Balsa wood is softer and more compressible in comparison to the hardwood. After getting moistened with saliva, the wedge becomes soft and conforms readily to contours bordering interproximal spaces between the teeth. However, some problems associated with fabrication and use of balsa wood wedge include uncertain source and supply, and a variance of properties, such as density, compressive strength, flexural strength, and cleanliness.

Tongue cleaners

The dorsum of the tongue provides a large area for the accumulation of various microorganisms, food debris, and dead cells. Furthermore, the tongue is inhabited by Candida species which is the cause of severe infections in immunocompromised patients ²³. These microorganisms along with food debris, dead cells, and salivary components form the so-called ‘tongue coating’. It has been shown that the micro-organisms isolated from the tongue coating were closely associated with those in dental plaque ²⁴ and those associated with periodontal diseases ^25-28. The anaerobic microbiota of the tongue biofilm has been found closely related to the development of halitosis.

     Various bacterial species isolated from tongue biofilm include Prevotella intermedia ^{29, 30}, Porphyromonas gingivalis ³¹, Aggregatibacter actinomycetemcomitans ³², Spirochaetes ³¹, Capnocytophaga ³³. Furthermore, it has been demonstrated that following the loss of all natural teeth, there is a decreased prevalence of selective periodontopathic bacteria on the tongue ^{27, 34}. All the above observations suggest that tongue cleaning should be an integral part of routine oral hygiene procedures. Unfortunately, most of the oral health professionals seldom recommend tongue cleaning, except for the cases of oral malodor.

     The tongue cleaning procedure was practiced by the Romans and was recorded in Europe in the 18th and 19th centuries. Ayurveda, the practice of Indian traditional medicine, suggests the daily use of the tongue cleaner in association with the cleaning of teeth to remove toxic substances from the dorsum of the tongue. In the Koran ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Assessment of tongue coating:

Winkel tongue coating index (WTCI) ³⁵ is used to assess tongue coating. In this index, dorsum of the tongue is divided into 6 areas (3 posterior, 3 anterior). The tongue coating is assessed as follows,

0 = no coating,
1 = light coating,
2 = severe coating.

All the scores from six areas are added and the final score is given with a possible range of 0-12.

Using a tongue cleaner:

The tongue cleaner is used by placing it as posterior as possible on the tongue. It should be pressed with gentle pressure to ensure full contact of the tongue cleaner with the tongue. Then it is pulled forward slowly, maintaining the tongue cleaner and tongue contact. The raised middle portion is used to clean the dorsum of the tongue. The smooth surface of the tongue cleaner is used to clean the lateral parts of the tongue. This procedure is repeated a number of times followed by mouth rinsing. One of the problems associated with the usage of tongue cleaner is stimulation of gag reflex, especially in persons who have just started practicing it. Patients should be instructed to place the tongue cleaner as back as possible without the stimulation of gag reflex.

Others

Gauze strips

The gauze strips can be easily used to clean plaque deposited on the teeth. It is specifically useful when a broad surface has been exposed due to loss of teeth, making plaque accumulation easy in that area. It may also be used to clean those areas which are not accessible to the toothbrush. It is readily available at home and can be used by moistening it and rubbing it gently around the gingival margin.

Oral irrigation device

The microbial accumulation in subgingival areas is the primary cause of initiation of periodontal diseases. The supra and subgingival irrigation with water or antimicrobial agents have been demonstrated to reduce the microbial load in the periodontal sulcus or pocket, reducing gingival inflammation ^36-39. The most important rationale for using intraoral irrigation devices is ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

     With the regular use of home and professionally applied oral irrigation devices, the periodontal health of patients can be improved. It has been demonstrated that patients on periodontal maintenance ^40-45, with orthodontic fixed appliances ^46-49, with crowns and bridges ⁵⁰, diabetics ⁵¹, patients with dental implants ⁵² and patients non-compliant to dental floss showed favorable results following regular use of intraoral irrigation ^{48, 53}. The first commercially available pulsating oral irrigator, Waterpik® was introduced in 1962. The device consisted of a plastic container to store water, a motor and tubing designed by a dentist and hydraulic engineer to generate water jet with pressure. Since then, many oral irrigation devices have been introduced for both professional and home use.

Mechanism of action:

When a stream of water is applied in the subgingival area, it expels bacteria and debris out of the sulcus, thus helping in reducing bacterial load in the periodontal environment. The two basic properties utilized in irrigation devices are pressure and pulsation. The initial devices were designed to deliver a continuous stream of water jet. Early studies showed a reduction in gingivitis but not in the plaque index. For this reason, the use of oral irrigators was restricted to orthodontic patients for many years until new irrigator devices with pulsating water jet were introduced. The pulsation of water jet results in the phases of compression and decompression of the tissue which not only helps in better removal of bacteria and debris from the pocket but also helps in the stimulation of gingival tissue ^54-56. It has been demonstrated that pulsating devices were three times more effective than continuous stream devices ^{54, 55}. Bhaskar et al. (1971) have shown that ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

      Another important factor which has been studied in subgingival irrigation by oral irrigators is the depth of delivery or irrigation solution. When water or any irrigation solution jet is put on the oral tissue surface, it created two different zones of hydrokinetic activity. One is the zone of impact where the solution initially makes contact with oral tissue and other is flushing zone, where the solution widens out in concentric circles and penetrates subgingivally ⁵⁷. The depth of penetration of irrigation solution also depends on the kind of tip used for irrigation. The standard tip which is used for irrigation has been found to result in around 50% penetration of complete pocket depth. However, the depth of penetration of the solution also depends on the pocket depth and angle of tip placement ^{58, 59}.

      Although, many tips are available in the market today, a tip that can be very helpful for periodontal patients is the Pik Pocket™ subgingival irrigation tip by Waterpik technologies. It is a soft latex-free rubber tip designed to fit Waterpik oral irrigators. One study has shown penetration of irrigation solution ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Use of antimicrobial solutions in oral irrigation:

The efficacy of various antimicrobial solutions has been compared with that of plain water in reducing plaque and gingival inflammation. A wide variety of solutions have been advocated for home irrigation, including chlorhexidine, acetylsalicylic acid, hydrogen peroxide, sodium hypochlorite, metronidazole and magnetized water ^{41, 44, 61-70}. The regular home usage of chlorhexidine irrigation is not recommended because it may result in staining of teeth. One study has demonstrated that irrigation with diluted (0.5%) sodium hypochlorite solution resulted in significantly greater and longer-lasting reduction in plaque and gingivitis as compared to irrigation with water ⁶⁵. However, patients may not comply with regular usage of sodium hypochlorite solution due to its bad taste.

     It must be understood that the plaque elimination by intraoral irrigators is primarily because of their mechanical action rather than the chemical action of the irrigation solution. Irrigation with antimicrobial solutions has been shown to increase the plaque elimination ^{40, 41, 43, 44, 69-72}. In one study, the effects of subgingival water irrigation were compared with that of water jet with 0.06% chlorhexidine on plaque reduction, marginal bleeding, and bleeding on probing. It was observed that water jet with chlorhexidine resulted in maximum plaque reduction ⁶⁹. It must be remembered that the subgingival irrigation ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Reduction in subgingival pathogens:

The reduction in subgingival pathogens by subgingival irrigation has been suggested as the primary biological mechanism involved in reducing periodontal inflammation. A lot of research has been done to evaluate the qualitative and quantitative changes in microflora in the periodontal pocket before and after application of intraoral subgingival irrigation devices. In one study, Newman et al. (1990) ⁷⁴ compared the effects of rinsing with 0.12% chlorhexidine (CHX) gluconate, irrigating with 0.06% CHX, and irrigating with water on the marginal and subgingival microflora in the subjects with gingivitis. All the subjects involved in the study used sodium fluoride dentifrice to brush their teeth. The data were collected at baseline, 3 months and 6-month intervals. All the groups were compared for Gram-positive cocci and rods, Gram-negative rods, and Gram-negative anaerobic rods and black-pigmented Bacteroides for logarithmic transformation (log10) of colony-forming units (CFU) and proportions (percent). The results of the study demonstrated that the reduction in CFU10 log, the percentage of Gram-negative anaerobic rods and the percentage of black-pigmented Bacteroides was maximum in chlorhexidine group. There was no significant difference found between water irrigation group and other groups in reducing the CFU log at 6 months.

     In contrast to these findings, Sanders et al. (1986) ⁶⁷ found no significant difference between most of the organisms measured from the irrigated and non-irrigated sites. The study compared supragingival irrigation with 0.02% CHX, 0.05% metronidazole, 0.01% quinine sulfate inactive control, and non-irrigated sites for measurements of micro-organisms in pockets ≥ 4 mm. However, some isolated differences were found between the groups for cocci at certain time points, favoring the irrigation sites.

     In another study ⁷¹, levels of Prevotella intermedia were found to be significantly reduced from baseline in the water irrigation group at 6 months and the 0.04% CHX irrigation group at 3 months interval after subgingival irrigation. Hurst and Madonia (1970) ⁴⁹ analyzed ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Effect on inflammation:

Multiple studies have reported a reduction in gingival inflammation after adding a dental water jet to tooth brushing as compared to tooth brushing alone ^{44, 45, 48, 51-53, 72}. In one study, Al-Mubarak et al. (2002) ⁵¹ studied the effects of subgingival irrigation in chronic periodontitis patients with type 1 or type 2 diabetes. 52 patients were included in the study. It was a single-center, single-blind, 3-month clinical and laboratory study. Scaling and root planing treatment was done on all the subjects who were then randomly assigned to either normal oral hygiene group (a manual toothbrush and any interdental device they used before the study) or the irrigation group with a subgingival tip plus normal oral hygiene. The results of the study demonstrated that the irrigation group showed significantly better improvement in measures, including gingivitis, plaque, and bleeding on probing, as compared to the controls. Further, the serum levels of interleukin-1 beta (IL-1β) and prostaglandin E2 (PGE₂) were significantly reduced from baseline in the irrigation group. The authors attributed these results to the host modulation effect of subgingival irrigation.

     In another study, Cutler et al. (2000) ⁴⁵ evaluated the changes in inflammatory parameters following daily irrigation with water in conjunction with routine oral hygiene measures. The pro-inflammatory mediators ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Fixed orthodontic appliances:

The patients undergoing orthodontic treatment are more prone to gingival inflammation due to food debris and plaque accumulation around orthodontic brackets. Intraoral irrigation helps in dislodgement of these deposits, thereby promoting periodontal health. Various studies have investigated the effects of dental jet devices on periodontal health in patients undergoing fixed orthodontic treatment ^46-49. In one study, dental water jet as an adjunct to tooth brushing was found to be 80% more effective than tooth brushing and rinsing in reducing the total aerobic flora and 60% more effective in reducing the lactobacillus count in orthodontic patients ⁴⁹. In another 2 months study, it was observed that the orthodontic patients who used dental water jet in addition to manual or powered toothbrushing demonstrated less plaque accumulation, reduced gingival inflammation and gingival bleeding as compared to patients using only tooth brushing ⁴⁷.

     Sharma et al. (2008) ⁴⁸ did a study on 105 adolescents undergoing orthodontic treatment, comparing plaque removal efficacy and the reduction in gingival bleeding with the application of a specifically designed orthodontic water jet tip + manual tooth brushing, brushing + flossing via a floss threader and manual toothbrushing alone. The results ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Bacteremia following subgingival irrigation:

The subgingival irrigation with oral irrigator devices is expected to result in bacteremia due to high pressure with which the irrigant is delivered. Studies have shown that incidences of bacteremia with the application of pulsating oral irrigators range from 7% in people with gingivitis ⁷⁵ to 50% in people with periodontitis ⁷⁶. However, the incidences are almost similar to that observed with routine oral hygiene measures such as tooth brushing and flossing (20% to 68%) and use of wooden toothpicks (20% to 40%) ^{77, 78}. Hence, oral subgingival irrigation can be used as an adjunct to standard oral hygiene procedures without any added risk of bacteremia.

Home use intra-oral irrigation:

The home use self-care devices for oral irrigation are widely available in the market these days. Most common of these devices are pulsed flow irrigators. One irrigator device for home use is pulsed flow, magnetized irrigator (Hydro Floss®). It is hypothesized that charged water decreases calculus formation as well as achieves the benefits found with non-magnetic irrigators 62. Some newer intraoral irrigators have been designed to water stream with micro air bubbles (Oral B OxyJet). They are proposed to help in better removal of plaque from the tooth surfaces. There are a variety of tips available for intraoral irrigation. Most commonly used tip is the standard tip which has been designed for supragingival placement.

     While using, the patient is instructed to direct the tip of the irrigator at a 90⁰ angle to the long axis of the tooth, placed approximately 3 mm from the gingival margin. After starting the irrigator, the tip is moved along the gingival margin and stopped at each interproximal area for five or six seconds, irrigating both the lingual and buccal aspects of the teeth.

Professionally applied intra-oral irrigation:

Intra-oral irrigation with various anti-microbial solutions has been shown to reduce plaque significantly greater than plain water. To take an advantage of these beneficial effects of intra-oral irrigation, many dental offices have incorporated irrigation to deliver antimicrobials subgingivally, especially after periodontal treatments. The antimicrobial solutions should be applied for an adequate time duration and frequency to achieve maximum benefit. Following subgingival irrigation, the bacterial counts return to baseline within one to eight weeks. For this reason, regular application of intra-oral irrigation is recommended in patients with periodontal diseases. The most widely investigated agent for intra-oral irrigation is chlorhexidine followed by 10% povidone-iodine solution (Betadine).

     The intra-oral subgingival irrigation in the dental office can be achieved by various methods. One method utilizes power scalers which utilize water or anti-microbial solution ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book ……… Contents available in the book  ……..

Conclusion

The mechanical plaque control is the cornerstone of oral hygiene maintenance procedures. In the present discussion, we discussed about various oral hygiene maintenance aids. However, all of these aids are not indicated for every individual. Except for toothbrushes, every mechanical oral hygiene aid has its own indications. Hence, it is recommended that every individual should be properly evaluated and should be prescribed oral hygiene aids as per his/her needs. In the next article, we shall read about various “brushing techniques”.

References

References are available in the hard-copy of the website.

Suggested reading

1. Westfelt E. Rationale of mechanical plaque control. Journal of clinical periodontology. 1996 Mar;23(3):263-7.
2. Van der Weijden FA, Slot DE. Efficacy of homecare regimens for mechanical plaque removal in managing gingivitis a meta review. Journal of clinical periodontology. 2015 Apr;42:S77-91.
3. Needleman I, Suvan J, Moles DR, Pimlott J. A systematic review of professional mechanical plaque removal for prevention of periodontal diseases. Journal of clinical periodontology. 2005 Oct;32:229-82.
4. Schroeder HE, Attström R. Effect of mechanical plaque control on development of subgingival plaque and initial gingivitis in neutropenic dogs. European Journal of Oral Sciences. 1979 Aug;87(4):279-87.
5. Iacono VJ, Aldredge WA, Lucks H, Schwartzstein S. Modern supragingival plaque control. International dental journal. 1998 Jun;48(S3):290-7.
6. Choo A, Delac DM, Messer LB. Oral hygiene measures and promotion: review and considerations. Australian dental journal. 2001 Sep;46(3):166-73.
7. Petersilka GJ, Ehmke B, Flemmig TF. Antimicrobial effects of mechanical debridement. Periodontology 2000. 2002 Jan;28(1):56-71.
8. Claydon NC. Current concepts in toothbrushing and interdental cleaning. Periodontology 2000. 2008 Oct;48(1):10-22.