From Volume 40, Issue 2, March 2013 | Pages 92-101
Pacifiers, otherwise known as dummies, have been around for many centuries. They have, however, taken many different forms, shapes and sizes. Their use is increasing and has remained controversial, with both potential risks and benefits identified in the medical and dental literature. The purpose of this article is to review some of the evidence available for and against the use of pacifiers and make recommendations for their application, maintenance and weaning.
Sucking is an inherent behaviour to the developing child at the intra-uterine, neonatal and infant stage. It has been observed that a foetus begins to suck his/her thumb as early as 12 weeks gestational age. This, together with some respiratory like movements, is thought to prepare oromusculature of the foetus for respiratory and swallowing function. The infants are also thought to have the sucking tendency as a part of two reflexes that exist only in early life: the rooting reflex which remains until 7 months of age and sucking reflex which remains until 12 months of age. The rooting reflex is where a child turns his or her head towards an object touching the cheek and this could be a finger or a mother's breast. The need for sucking can be satisfied through nutritive sucking, which includes breast and bottle feeding, or non-nutritive sucking on items such as digits, pacifiers or toys.
Pacifiers, also known as dummies or baby soothers, have been used to calm babies for centuries. The first evidence for their use recorded in medical literature dates to a book written by Metlinger in 1473.1 There is also evidence of their use in society in the form of ornaments or pieces of cloth that remain to this day. These would have either been filled with food or sweetened liquid to calm down the baby on sucking. A Madonna and child painted by Dürer in 1506 shows a tied-cloth ‘pacifier’ in the baby's hand (Figure 1). It has also been suggested that, in some cases, even alcohol or opiates may have been used to help the baby get to sleep.2 Pacifier use was a widespread practice up until the turn of the 19th Century in many parts of Northern Europe and elsewhere. In the 19th Century, an anti-pacifier movement grew in America and Europe which objected to its use, the reasons being that it encourages poor oral hygiene and pleasure-seeking behaviour. More recent evidence suggests that approximately 75–85% of children in western countries use a pacifier.3
A large number of studies have looked into the medical and dental effects of dummy-sucking. The dental literature in the past has been mainly focused on the use of pacifiers and the risk of their use in relation to the developing malocclusion. There have also been reports of their use being related to an increased prevalence of caries,4 oral infections5,6,7 and the risk of developing a temporomandibular joint dysfunction.8 In the medical literature, other aspects of pacifier use have been investigated, some of which are beneficial and others with the potential to cause harm. Based on the World Health Organization (WHO) Evidence for the Ten Steps to Successful Breastfeeding, published in 1998,9 women should be informed about the benefits of breastfeeding in the first six months of life and be discouraged from providing artificial treats or pacifiers to breastfeeding infants. The American Academy of Pediatrics Clinical Practice Guidelines, 200410 slightly differ in that they only discourage pacifier use from the second six months of life. The lack of general consensus amongst different bodies highlights that more conclusive research is needed in this area. The purpose of this article is to discuss some of the known effects of the use of pacifiers in the first five years of life.
Pacifiers have been used as a measure to provide pain relief during minor procedures such as catheterization, circumcision, immunization, insertion of an IV line, lumbar puncture and venipuncture. The evidence for their use comes from a number of randomized control trials. A systemic review article published by Stevens et al11 in the Cochrane Database concluded that sugary solutions may be of some benefit in children for reducing pain. The pain experienced by subjects was assessed by measuring their physiological response (eg heart rate) and behavioural pain indicators (eg crying pattern and facial expressions), as well as composite pain scores. This study did not investigate the optimal dose or route of administration. The delivery method of sucrose varied between studies examined in this paper. Sucrose was delivered to the infant by syringe, dropper or pacifier. It can be argued that a pacifier promotes non-nutritive sucking and the ensuing calming effect may also contribute to reducing pain-elicited distress compared to other routes of administration.
Sudden infant death syndrome is defined as ‘the sudden unexpected death of an infant less than two years old with peak occurrence of two to six months from an unidentifiable cause’.10
There are many factors attributed to SIDS. In 1996, the British Medical Journal launched a population-based case control study based on a two-year period into risk factors associated with SIDS. The study found that a side sleeping position, co-sleeping with someone who is a smoker or has consumed alcohol, infants sleeping in a room alone, use of duvets and pillows, whether bedclothes covered the infant's head, and postnatal exposure to tobacco smoke to be the main factors predisposing children to the risk of SIDS.12
The strongest evidence for pacifier use to reduce the incidence of SIDS comes from Hauck et al,13 who carried out a meta-analysis of case control studies and found that one death can be prevented for every 2733 pacifiers used. Table 114 highlights some of the possible ways in which pacifiers may produce this effect. The recommendation made from this paper was for infants to keep the pacifiers until the age of one year, when incidence of SIDS is much reduced.
| It is believed that the use of pacifiers before 12 months of age can help to prevent Sudden Infant Death Syndrome in the following hypothetical ways: |
However Hauck et al13 also recommended that, for children that are breastfed, it is best to avoid pacifiers in the first month of life until breastfeeding ability is well established. This is further supported by the fact that the risk of SIDS is found to be low in the first month of life.
The prevalence of digit-sucking appears to be inversely related to a pre-existing pacifier-sucking habit. Two studies have highlighted this phenomenon. The first study took place in Israel and showed that children in one area, where access to pacifiers was withdrawn, had a higher prevalence of thumb-sucking habit than those who were given pacifiers in another region.15 In a second study, Larsson and Dahlin16 carried out a retrospective study which showed the decline of digit-sucking habits from the 1940s to the 1980s, in line with the increased use of pacifiers in society.
There is some evidence that children and, in particular, girls who cease from dummy-sucking may resort to nail-biting and digit-sucking to satisfy their urge.17
Breastfeeding is generally thought to be superior to bottle or any other form of feeding as the breast milk is the best source of nutrition for infants. The Department of Health encourages mothers to breastfeed during the first six months of life. After this period, breastfeeding may be continued or weaned and substituted with bottle feeding.18
It has been suggested that the use of a pacifier may encourage early weaning from breastfeeding.19 However, evidence based on several randomized control trials does not show pacifier use to be adversely affecting breastfeeding duration or its non-use.20–23
Some authorities recommended avoiding pacifiers just for the neonatal period whilst the child is developing a breast-sucking reflex (ie the first 28 days after birth).24
Otitis media is inflammation of the mucosa lining of the tympanic cavity, which may be of bacterial or viral origin. The condition arises when the pathogenic organisms find access via the Eustachian tube to the middle ear. It is most common between the age of 3 months and 36 months, when children also happen to be in contact with pacifiers. The connection of the middle ear with the oral cavity via the Eustachian tube raised the question for more than a century of whether pacifiers could be a preventable risk factor for contracting otitis media. There are several ways in which pacifier use is postulated to lead to middle ear infections3,25 and these are summarized in Table 2.
| Alternation of oropharyngeal function |
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| Pacifiers transfering and promoting growth of pathogens |
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| Reduced benefits of breastfeeding |
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A randomized control trial3 and a dynamic cohort study26 show significant association between acute otitis media (AOM) and pacifier use. In the meta-analysis of Uhari et al,27 pacifiers were found to be one of the main risk factors for the development of acute otitis media, accounting for a 24% increased chance of contracting the disease.
Pacifier-sucking can be considered to be a form of oral parafunction. Oral parafunctions, such as bruxism, are associated with the development of temporomandibular joint dysfunction (TMJD). It can be argued that pacifier-sucking may alter the facial skeleton and its associated soft tissues such that tendency for TMJD is increased. There is limited evidence to support this view and the evidence thus far fails to indicate a direct link between pacifier use and temporomandibular joint dysfunction.8
The pattern of facial growth and dento-alveolar development is partly determined by genetic factors and partly by environmental factors. Amongst the environmental factors, the pressure exerted by soft tissues of the lips, cheek and the tongue has a major influence in determining the shape of the dental arch, as well as tooth position.28 Pacifier-sucking is different from a breast-suckling habit and therefore may alter soft tissue pressures whilst growth is taking place (Table 3).
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These forces are thought only to have significant effects on teeth and arch form if they are continued for more than six hours a day. Any duration less than this does not initiate cellular mechanisms that are required for the alteration of tooth-tissue structure.29
In a non-nutritive sucking habit, a negative pressure is created, mainly in the canine region.30 This negative pressure reduces the maxillary arch width.31 As maxillary arch width is reduced, discrepancies in maxillary and mandibular arch shape, and in tooth position, may lead to the formation of cross-bites, which are commonly unilateral and posterior.32
‘Suckling’ involves the child putting both the nipple and areola into the mouth and it is the movement of the lips and tongue that brings about the suckling motion. In dummy ‘sucking’ the child presses the tongue in a piston-like motion in the direction of the palate to compress the artificial teat.33
The prolonged presence of a pacifier in the anterior section of the mouth could theoretically also exert pressures that restrict vertical maxillary development, reduces the overbite and creates an anterior open bite (Figure 2). This distortion is likely to be circular in shape owing to the shape of pacifiers whilst they are placed in the mouth.34
In fact, the available evidence suggests that the long-term effects of pacifier-sucking on skeletal maturation are negligible. Most children stop the habit by the age of seven years.34 A retrospective cephalometric study carried out by Larsson17 on 134 subjects showed no significant difference in the skeletal pattern of those children who sucked pacifiers and those who did not in their earlier years.
It has been postulated that a prolonged non-nutritive sucking habit can lead to the development of an anterior tongue thrust with its associated anterior open bite,35 which is difficult to treat and requires a combination of mechanical and myofunctional orthodontics if the habit is not ceased early.
The pacifier can be made either out of latex or silicone. Pacifiers come in contact with the extra-oral environment and can act as a medium for the transfer of pathogens into the oral cavity. Latex material tends to be more receptive to the formation of a biofilm.36–38 Evidence comes from studies that have mainly focused on the transfer of cariogenic bacteria, Staphylococcus aureus and Candida as they account for a large proportion of the infections in the oral cavity. The results indicate all three types of organisms can be colonized from the biofilm on the pacifiers.5,6,7 Ollila et al6 suggested the following ways in which pacifiers may facilitate growth of pathogens:
Strict maintenance of hygiene and an efficient antibiofilm cleaning protocol should be established at home to reduce the chances of infection.36 The current guidance from the Department of Health states that the bottle teats should be cleaned using soapy water after every feed and sterilized, either using cold sterilization (eg using Milton's which is a stable solution of sodium hypochlorite) or steam sterilization (microwave or electric steam sterilization). No recommendations specific to pacifier sanitization is available on their website.
Pacifiers coated with sugary substances pose a high risk for developing caries, particularly in the anterior region of the maxilla, where most contact with the pacifier is made. This effect was first noted by Jacobi in 1861.39 Since then many studies have linked sweetened pacifiers to the development of caries in the deciduous dentition. This type of ‘comforter caries’ usually appears at or near the gingival margin of the tooth, more commonly on the labial than the palatal aspect. Deciduous teeth are often affected in chronological sequence as they erupt. Lower incisors are somewhat protected by the action of the tongue, lower lips and saliva produced from the sublingual glands. With the progression of caries, the colour of lesion changes from a whitish decalcification area (with or without pitting) to a light yellow colour. With time, caries may spread to proximal surfaces and involve the incisal edges. By this stage, the tooth is greatly weakened and becomes susceptible to fracture from minor forces.40
The ability of pacifiers to promote caries may also be related to their potential to harbour cariogenic bacteria and reduce salivary flow. Although sweetened pacifiers can lead to dental decay, the evidence so far fails to show a clear link between non-sweetened pacifier use and increased prevalence of caries.41 The general consensus is that, if pacifiers are used, the best practice is to avoid coating the pacifier with sugary substances to prevent caries.40
Pacifier-sucking peaks at around one year of age and declines thereafter.42,43 The majority of children stop the habit by the time permanent dentition erupts.34 For those few who continue the habit, they can be weaned off pacifiers simply by withdrawing the pacifier. Alternatively, a stepwise manner in eliminating the habit can be employed, gradually reducing its use to key times during the day when it is needed, such as bed-time or when the child is ill. Children can be rewarded with stickers or star charts so that a positive attitude is attained. If a child is reluctant to stop using the pacifier, it may work if the child is encouraged to leave the pacifiers with someone who they trust, such as grandparents, school worker or others. Positive reinforcement may also be obtained through modelling other children who have grown out of their habits. For a child of an older age when permanent dentition is through, the cessation of pacifier-sucking may be achieved through the use of an upper removable appliance that hinders placement of the pacifier into the oral cavity and acts as a reminder for the child.
In the 1950s, a new type of pacifier was introduced that was designed to encourage the natural sucking motion that is carried out during breastfeeding. These are made such that the teat is oval in cross-section and has vents to allow collapse of the teat during sucking (Figure 3). There are limited studies to demonstrate the effectiveness of these orthodontic pacifiers. In a study by Adair et al,44 no significant difference was observed in the dento-alveolar development of conventional and orthodontic pacifier users.
The decision to use pacifiers in infants and children remains controversial. The studies reviewed in this paper would indicate that there are potential risks and benefits to be gained from pacifier use. Appropriate use of pacifiers at the right age seems also to protect against SIDS, which is a life-threatening phenomenon. However, further research is needed in these areas to validate these suggestions. Owing to the lack of strong evidence, it is not possible to make firm conclusions. Based on this review the following recommendations can be made:
