Oral changes in cocaine abusers: an integrative review

Highlights • Integrative review aiming to detect oral changes in cocaine abusers.• The main oral changes, methods of diagnosis and treatment were identified.• Good anamnesis and qualified health professionals are necessary.


Introduction
A psychoactive drug is defined as a chemical, natural or synthetic product that, when administered by any route (inhalation, ingestion, intramuscular, intravenous) acts on the central nervous system and triggers physical and/or psychiatric alterations, causing changes in sensations or modifying the psychological state, i.e., altering the individual's behavior. 1 The consumption of psychoactive substances can be influenced by the users' social context and factors such as family income, level of schooling and place of residence. 2 In this sense, drug abuse is considered a public health problem due to the systemic and behavioral consequences. 3,4 Among the most common and most frequently used illicit drugs worldwide is mainly Cannabis sativa, popularly known as marijuana. 5,6 In addition, there are amphetamines, ecstasy, opiates and cocaine. 7 Benzoylmethylecgonine is a relatively recent drug among the psychoactive substances used by humans over time and can be found in and extracted from the leaves of the coca plant (Erytroxylus coca), which can reach the consumer through three different forms: in the form of salt, cocaine hydrochloride, and as powdered cocaine, which can be aspirated or dissolved in water for intravenous use. 8 Derived from cocaine, crack cocaine consists of a base, transformed into crystals, poorly soluble in water and volatile when heated, which can be smoked in pipes. Regardless of the type of drug use, all the effects are caused by the use of both; however, when smoked, they show greater potency. 8 Currently, cocaine is classified as a psychoactive substance that belongs to stimulating drugs that alter brain function, making it more active, acting on the central nervous system. 9,10 The consumption of this drug can be carried out in several ways; one of the main forms of cocaine administration is the intranasal route. 11 A few minutes after inhalation, a feeling of euphoria occurs, which lasts around 20−90 min.
Moreover, cocaine users can rub the drug on gingival tissue due to the similar architecture of the nasal and oral mucosa and abundant vascularization. 12 However, with this type of use, when rubbed on the gingival surface for more effective absorption, powdered cocaine can lead to irritation of this mucosa. E. coca absorption by the mucosa can cause oral lesions as a result of decreased blood supply due to vasoconstriction in the affected region, resulting in tissue necrosis. 13 As a consequence, drug abuse can cause or result in the occurrence of physical problems such as car-diac complications, respiratory depression, liver cirrhosis, nephropathy, or it can indirectly cause infectious diseases, such as hepatitis, AIDS and tuberculosis. It can also cause disability and mental disorders, such as depression. These conditions can progress to more advanced stages and cause significant disorders, as it often takes addicted patients some time until they seek medical care and they do so when symptoms worsen. 14 In addition to the consequences of cocaine use for one's general health and the systemic effects of the drug, it is also necessary to consider the occurrence of oral changes in users, 15 since the substance use can directly affect the dental tissues and the oral mucosa, which may cause xerostomia, changes in salivary flow, enamel erosion and abrasion, atypical caries, tooth loss 14 and gingival lesions. 10 Moreover, the regular use of cocaine can have serious orofacial effects, such as perforation of the nasal septum and palate, gingival lesions and tooth surface erosion, in addition to being associated with changes in the sense of smell and chronic sinusitis. 16 In this sense, the present study aimed to identify the oral alterations most commonly found in individuals who abuse cocaine, in addition to their diagnoses and treatments, available in scientific publications.

Methods
The steps of this integrative literature review were independently carried out by three researchers following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA). 17 For a better construction of the present study, the PICO strategy (population, intervention, comparison and outcome) was used to set up the question. 18 Based on this strategy, the following question was created: What are the most common lesions found in the oral cavity in users who abuse cocaine?

Search strategy
The search for the studies was carried out from September to November 2020, in the following databases: LILACS, BBO, LIS and MEDLINE via the Virtual Health Library (VHL) portal, Scientific Electronic Library Online (SciELO), Science Direct and MEDLINE via PubMed. Variable combinations of descriptors obtained from DeCS (Health Sciences Descriptors) and MeSH (Medical Subject Headings) in English and Portuguese (Table 1) were used in the search.

Study eligibility criteria
Studies that showed results related to lesions found in the oral cavity of cocaine abusers were included. The inclusion criteria were: original articles, articles in Portuguese, English and Spanish, case reports, cross-sectional studies, experimental studies, observational studies and field studies. There were no restrictions regarding the year of publication. Studies in animals, literature reviews, book chapters, theses and dissertations were excluded.

Study selection
After searching the databases, the titles and abstracts were listed in a standardized manner. Then, articles in duplicate were excluded, and based on the inclusion and exclusion criteria, the initial selection of studies that had the potential for full-text reading was performed. In case of disagreement, a fourth reviewer was consulted, and the decision was made by consensus. The full texts that were not available in the databases were requested directly from their authors. A manual search was also carried out in the list of references of the articles considered eligible. After reading the texts in full and deciding to include the articles in the present study, the most relevant results were extracted for sequential analysis.

Results
The electronic and manual search resulted in the identification of 1373 articles. Of these, after the initial exclusion by titles and abstracts, a total of 26 articles were selected according to the eligibility criteria. Finally, after reading the texts in full, 22 articles were included in the review. The study flowchart can be seen in Fig. 1.
The overall characteristics of the 22 selected articles can be seen in Table 2. The number of individuals in the studies ranged from at least one participant (case reports) to a maximum of 212 participants. The mean age of the individuals who participated in the studies ranged from 13 to a maximum of 70 years.
Regarding the type of study, of the 22 analyzed ones, 13 were case reports, 20---23,28---34,36,38,39 five were cross-sectional studies, 15,19,26,35,37 one was an experimental study, 24 two were observational studies, 26,35 and one was a field study. 25 Although literature reviews constituted an exclusion criterion, two studies 20,31 were included because they had more than one methodological type, being two case reports that contained literature reviews in their methodology.
Regarding treatments, some authors stated that the patient's oral manifestation must be taken into account and based on it, the best method of treatment that can be performed is determined. In patients with palatal perforation, reconstruction of the affected area is usually necessary, performed using flaps from the same palatal region or not, 20,21,23,27,34 or the use of adipose tissue from Bichat's fat pad 34 or the use of prosthetic obturators, 20,21,27,29,32,33 surgical reconstruction of the facial midline 23 or even salivary stimulants. 19

Discussion
This integrative review addressed the most common oral disorders found in individuals who abuse cocaine. The studies included in the review were mostly case reports and cross-sectional studies. The results showed that the most frequent types of oral alterations were palatal perforation, 20,22,26---29,31,33,34 bruxism, 25,33 periodontal diseases, 24---26,35 and presence of caries. 24---26,33 The main strategies used in the examination and diagnosis were The most frequently used drugs were crack, followed by cocaine and marijuana. There is a predominance of caries (87.5%), followed by the presence of signs of periodontal disease.   Only a few authors mentioned strategies to rehabilitate or replace oral tissues partially or completely destroyed by cocaine use. 20,21,23,27,34 Regarding the most common oral manifestations, it is necessary to consider that because cocaine has a high vasoconstrictor effect, it is possible that its use leads to the ischemia of soft and hard tissues of the oral cavity and, consequently, their necrosis. 20 This destructive process can cause ulcers or perforation in the hard and soft palate, culminating in an oronasal communication and a consequent nasal voice, 23,25,32 difficulties in eating and drinking 20,39 and even nasal regurgitation. 20,22,27,29,31 These were the patients' main motivations for seeking professional help. However, some studies mentioned that some users did not allow this identification, as they kept denying the drug use, aiming to avoid hospitalization or judgments. 20,21 Perforations can happen during the drug abuse period or even years after drug use discontinuation. For that to occur, the presence of an inflammatory process is necessary, through bacterial, viral 40 or fungal infections, which are usually also associated with ageusia. 24 In addition to these, inflammatory diseases associated with systemic diseases 21,30 or physical or chemical aggressions can be related to this type of alteration. In the case reported by Dovigi and Natarajan, 28 an individual with extensive bone loss in the palate and nasal septum caused by years of cocaine use experienced an oronasal communication after burning the ''palate'', making it impossible for him to eat comfortably, as everything invaded his nasal passage.
Regarding oronasal communications, the literature indicates that they can be small and transient, 20,28,31 extensive 23 or also multiple. 29,33,39 As they are anatomically very close to the palatal region and because they lack cartilaginous vascularization, it is also possible they are commonly accompanied by nasal septum perforations and destruction. 22,30---32 In addition to the previously mentioned consequences, patients who are addicted to cocaine may also have muscle disorders and, therefore, possible temporomandibular disorder. 33 Chaparro-González et al. 25 corroborates this finding by identifying that users of drugs such as cocaine, methamphetamine and opioids suffer from bruxism, which results in a higher frequency of TMD. An evaluation of the presence of harmful oral habits in the analyzed sample shows that 59.4% had bruxism, and 37.5% had onychophagia. 25 The form of cocaine use can be variable and the direct use of cocaine by rubbing it on the gums is one of them. This type of use acts as a substance purity test and can cause gingival recession, ulceration and necrosis. 20,36 An observational study showed that none of the addicts had periodontitis; however, 28 of the 43 patients had some form of gingi-val disease. Of the total number of affected individuals, five had mild gingivitis, 17 had moderate gingivitis and six had gingivitis with a periodontal pocket formation according to Russel's index. 35 Regarding oral manifestations in drug addicts, the most frequent condition in oral hard tissues is a high prevalence of caries, 25 due to the fact that drug users commonly neglect their oral hygiene. 24,26 A significant reduction in salivary flow was observed among cocaine users, with reports of xerostomia. 19,33,39 Moreover, cases of ageusia were described, and when drug addicts were compared to non-users, addicts showed a loss of taste especially regarding the sweet, bitter and salty flavors, indicating that cocaine abuse causes salivary and gustatory alterations, 24 caused by the damage to taste receptors, either directly or through secondary processes, altered production and composition of saliva and mucosal elements, changes in the processing of sensory information related to the palate and cortex 24 and oral mucosa dryness. 19,33,39 The physical examination is the fastest and most efficient way to identify palatal lesions. 25,29,35 For individual planning, two-dimensional examinations should not be the only form of diagnosis, and the use of three-dimensional images is essential, since the reference points, lines and plans facilitate a better understanding of cases with greater severity. 41,42 When necessary, to assess the extent of the lesions and have a better knowledge of their location, the use of head and neck CT can be requested, 20,22,23,32,33 aiming to reveal the structural relationships in depth, and show individualized images of the human body, which reduces the overlap of structures, thus obtaining a clear image. 43 Still in this context, it is important to emphasize that a good medical history can better direct the professional towards a more assertive diagnosis and treatment. 31,44 As the lesions investigated in the present study are associated with the use of illicit substances, sometimes the user/patients can deny their use, 21 making diagnosis difficult and delaying the start of the therapy.
In addition to the tomography, histopathological examinations of incisional biopsies of these lesions are carried out, which can often disclose the existence of acute, chronic and necrotizing inflammatory characteristics, 19,32 or even lacking necrotizing characteristics. 38 These examinations can be extremely important in clinical diagnosis, as different types of diseases can cause destructive lesions in the oral cavity that are similar to lesions caused by cocaine use. 31 The incidence of palatal perforations caused by cocaine use is likely to increase when left untreated. 20 More extensive defects can directly impair functions such as speech and mastication; however, obturator prostheses can minimize these problems, as they are a conservative and non-invasive form of treatment. 20 Another possible therapy is surgical intervention. 20,21,23,27,34 However, it is observed that treatment with an obturator prosthesis, as a palliative and less invasive measure, is often sufficient. 28,33,39 In specific cases of destructive lesions of the facial midline caused by cocaine abuse, 23 surgical reconstruction procedures are recommended. This surgical reconstruction can be especially indicated when the defect is located in the soft palate. 27 In cases where the hard and soft palate tissues are affected, there is an alternative, in which these structures are removed and subsequently replaced by a prosthesis, part of which is made of acrylic for the hard palate, whereas the other part is made of a resilient and malleable material used to replace the soft palate. 29 Another option is to use the Le Fort I osteotomy surgical technique and the use of a bilateral Bichat's fat pad flap, which is an effective method for the correction of small and medium-sized oronasal communications. This technique is easy to perform, and has a minimal impact on the patient's aesthetic appearance. 34 In this sense, this procedure is an effective alternative for young and elderly patients, guaranteeing an excellent intraoral approach in addition to great aesthetic result.
The present study has limitations that must be considered, as the studies used in this review may not represent the general population, 15,19 had a small sample size, 26,37 and showed difficulties locating the users that were addicted to a single drug. 37 In the study by Cury, 26 a sampling error of 5% was found and no correction factor was used; men addicted to cocaine were less cooperative during the oral examination, and there was also the possibility of bias in the response to the questionnaires applied to participants.

Conclusion
Several oral manifestations caused by cocaine abuse were identified, with the main ones being: palatal perforation, predisposition to periodontal disease, damage to oral tissues and presence of dental caries. Different approaches were used to attain a diagnosis, which had a direct effect on treatment. Therefore, it is necessary for health professionals to be able to recognize these alterations and manifestations, so that an accurate and assertive diagnosis and treatment planning can be carried out. A public health program aimed at the early diagnosis and treatment of lesions resulting from drug abuse is vital to improve the oral health of individuals who abuse cocaine.