Is a drill-less dental filling possible? Ryan L. Quock ⇑ , Shalizeh A. Patel, Felipe A. Falcao, Juliana A. Barros Department of Restorative Dentistry and Biomaterials, University of Texas at Houston Dental Branch, 6516 M. D. Anderson Blvd., Ste. 493, Houston, TX 77030, United States article info Article history: Received 11 November 2010 Accepted 2 May 2011 abstract Dental caries, a bacterial process that results in the acidic destruction of tooth structure, has historically been managed by the mechanical excavation of diseased tooth structure and then restoration with a syn- thetic material. The mechanical excavation of the infected site is most commonly achieved by a dental handpiece, or ‘‘drill’’; this handpiece may induce stress and anxiety in many patients. Alternatively, a drill-less filling will involve the utilization of silver diamine fluoride (38%) to arrest and prevent dental caries, followed by restoration with a bonded filling material to achieve adequate seal at the lesion mar- gins. This is a minimally invasive procedure that addresses both microbial and mechanical issues posed by dental caries. Ó 2011 Elsevier Ltd. All rights reserved. Introduction Dental caries is the bacterial process more colloquially known as tooth decay. Acid-producing bacteria, such as Streptococcus mutans, lower intraoral pH levels such that the mineral content of tooth enamel decreases. Similarly, if intraoral pH levels are raised, this process is reversed and tooth enamel can remineralize. In general, the pendulum swings between demineralization and remineralization, depending on pH level [1]. However, if teeth are persistently exposed to acidic environments of less than pH 5.5, demineralization of tooth structure can become irreversible – the resulting cavitation is not remineralizable. The traditional treatment for a cavitated tooth involves mechanical excavation of infected, irreversibly demineralized tooth structure and replacement with a synthetic filling material. In fact, the primary reason supporting operative preparation and filling of a tooth is to repair destruction from a carious lesion [2]. Excavation of a cavity site is most commonly achieved with a ro- tary dental handpiece, often thought of as a ‘‘drill’’ by patients. Such handpieces are able to efficiently remove infected tooth structure, as well as shape the remaining sound tooth structure. The intuitive philosophy is that the removal of bacteria-rich in- fected tooth structure will, at least in an acute sense, minimize risk of disease progression, especially if a well-adapted filling is placed in the cavity space. Arresting dental caries progression is especially important because if left untreated, it can result in systemic infec- tion [3]. A difficulty for the dental practitioner is that the very drill that is used to help treat the dental caries is often cited as trigger- ing patient fear and anxiety [4]. It is conceivable that this fear of the dental drill may be strong enough to deter some patients from seeking the intervention that is needed. As our understanding of caries progression has expanded, along with the improvements in dental materials, a more minimally invasive perspective towards caries management has arisen. Cavity preparations with the dental handpiece are kept to a minimal size, and then restored with a correspondingly conservative adhesive restoration [5]. Small cavity preparations and fillings are valued in minimally invasive dentistry not only for the immediate preser- vation of natural tooth structure, but also long term tooth-preser- vation – over the lifetime of a tooth, there is a tendency for replacement restorations to be increasingly larger in size, reducing the remaining natural tooth structure [6]. Despite advances in min- imally invasive dentistry, the use of dental drills (or some other form of mechanical excavation) continues. Hypothesis A drill-less approach to treat a cavitated carious tooth lesion will involve two steps: (1) arresting bacterial activity with 38% sil- ver diamine fluoride and (2) restoring the cavity space with a bonded resin-based composite filling. Silver diamine fluoride Cavitated dental caries lesions present several related problems for the patient. First, by definition, the cavity is formed by the col- lapse of demineralized tooth structure. This tooth structure col- lapses because, due to bacteria-generated acid attack, it has lost too much mineral content to remineralize. Second, along with con- taining softened and demineralized tooth structure, a cavity is also populated by a large quantity of cariogenic bacteria. Thus, the tooth cavity serves as a niche for an ever-multiplying colony of bacteria, such as S. mutans and Lactobacilli [7]. And thirdly, fer- mentable carbohydrates in the patient’s diet are easily trapped in a dental cavity; carious bacteria treat these carbohydrates as the 0306-9877/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2011.05.002 ⇑ Corresponding author. Tel.: +1 713 500 4276; fax: +1 713 500 4108. E-mail address: Ryan.Quock@uth.tmc.edu (R.L. Quock). Medical Hypotheses 77 (2011) 315–317 Contents lists available at ScienceDirect Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy