Role of nanotechnology in dentistry: a systematic review

INTRODUCTION

“Curiosity is the mother of invention”, and it holds true in today’s modern era of science and technology. Man’s quest to create a new technology, which is better and more efficient, has led to the introduction of nanotechnology, a technology that deals with structures ranging in size of 100 nanometers or less in at least one dimension [1].
The term “nano” is derived from a Greek word meaning “dwarf”, and first definition of nanotechnology has been introduced by a Japanese scientist, Dr. Norio Tani­guchi in 1974. He defined it as a process of separating, consolidating, and deformating materials by one atom or one molecule [2]. The late Nobel Prize winning physi­cist Richard P. Feynman, contemplated the potential of nano size devices as early as in 1959. In his historic lecture called “There’s plenty of room at the bottom”, he concluded by saying: “This is a development, which I think cannot be avoided”. The term “nanodentistry” was invented by R.A. Freitas Jr in the year 2000.
The basic idea of nanotechnology is to employ individualatoms and molecules to construct functional structures. Nanotechnology has revolutionized all fields from healthcare to engineering into a new archetype beyond traditional, and dentistry is no exception.
The aim of this systematic review of the literature was to evaluate and summarize the role of nanotechno­logy in dentistry.

METHODOLOGY

This systematic review was based on PRISMA (preferred reporting items for systematic reviews and meta-analyses).

FOCUSED QUESTION

Does nanotechnology have an effective role in dentistry for management of oral diseases?

SEARCH STRATEGY

The literature was searched systematically, and studies published between June, 2020 to October, 2020 were taken into consideration. Electronic database search of PubMed, Medline, Cochrane, and clinicaltrials.gov were examined holistically. Key words used for the literature search included “Nanotechnology”, “Nanotechnology in dentistry”, and “Nanotechnology in dental practice”. Articles published in last 6 years, i.e., from 2014 to 2020, were reviewed. Additionalmanual search was also conducted by two authors, Akanksha Raj and Ali Atif, for off-line publications. Duplicated and repeated articles were excluded (Figure 1).

INCLUSION AND EXCLUSION CRITERIA

Random clinical trials (RCT) that have been published in last 6 years and were published in English language only. Exclusion criteria were articles not relevant to dentistry, letters to editor, short or rapid communications, review articles, observational studies, phase I clinical trials, editorials, case reports, articles published before 2014, and articles published in any other language than English.

EXTRACTION OF INFORMATION

Data extraction was performed by review author and an assistant researcher after assessing all selected articles, such as RCT to evaluate biasing risk, and data was extracted using data extraction form.

RISK OF BIAS ASSESSMENT

Risk of bias assessment was performed according to guidelines issued by Cochrane, and was done under following domains (Table 1). Accordingly, studies were divided into 3 domains (Table 2).

RESULTS

SEARCH RESULTS AND EXCLUDED TRIALS

900 papers were retrieved in initial electronic search, and 6 clinical trials were identified when search was performed by review authors manually. In first stage of screening, 194 papers were selected based on the title and abstract. 14 clinical trials were selected, but only 11 were identified for inclusion, as for 2 clinical trials data was insufficient due to results not given and for 1 clinical trial, full text could not be found. 38 review articles, 18 animal studies, and 1 letter to editor, along with 1 editorial were excluded. In vitro studies and ex vivo studies were also excluded. Summary of studies are presented in Table 3.
Risk of bias assessment was also performed according to guidelines given in Cochrane handbook, and results are presented in Table 4.

DISCUSSION

Nanotechnology has an effective role in the management of the following oral diseases:
1. A study evaluating effectiveness of nano-hydroxy­apatite (nHA) toothpaste in reducing dentinal hyper­sensitivity problem was conducted, and results showed that nHAP toothpastes had better re-mine­ralization effects than fluoridated toothpastes [6]. Other study showed that 20% nHA toothpaste or dental cream has an effective role in treating dentinal hypersensitivity when applied daily [10].
2. In a double-blinded randomized controlled clinical trial conducted on 20 teeth of 10 patients of age 18-21 years, showed that 10% of nHA solution has an effective role in increasing micro-hardness of enamel in permanent teeth, following exposure to soft drinks [14].
3. A study done on 159 lesions in 50 children of age 6-10 years concluded that effect of applying 5% nano-silver fluorides annually has same effect as that of 38% silver diamine fluoride in prevention of caries progression in primary molars, and also concluded that its’ application does not stains dentinal tubules [7].
4. In cross-over clinical trials, nano-sodium fluoride (nNaF) can be used as an anti-biofilm, as it has proven to have bactericidal effects against Streptococcus mutans. Hence, nNaF can be used in clinical control as well as in prevention of oral biofilm formation [11].
5. Nanogen and BoneGen TR can be used to treat infra-bony periodontal defects as stated by authors, who conducted their study on 16 individuals in age range of 20-64 years [8].
6. Nano-surface-treated implants: Results have shown that no statistically significant difference was found when comparing laser collar and nano-surface-treated implants in terms of PD, including probing depth, modified bleeding index, and assessment of implant mobility at different follow-up intervals. Amount of bone loss observed was consistent with peri-implant tissue stability observed at 12 months. Also, bone loss had not caused any implant mobility [9].

LIMITATIONS

For the present systematic review, articles published in English language only were considered, which may lead to biasing in results and interpretations.
Due to non-availability of sufficient number of clini­cal trials, effective assessment of various interventions could not be done.

CONCLUSIONS

It can be concluded that nanotechnology has a pivo­tal role in prevention and management of oral diseases. The use of nanotechnology in treatment of dental diseases has been extended to treat dentinal hypersensitivity, dental tissue re-mineralization, treatment of dental implant’s surface, prevention of formation of oral biofilm, and prevention of progression of dental caries [17]. Nanotechno­logy in dentistry may have an important role in maintaining oral health, but the risk and toxicity associated with these nano-therapeutics may need extensive research for better understanding [18, 19].

CONFLICT OF INTEREST

The authors declare no conflict of interest.

References