Looking Back and Looking Forward at Dentistry - A Centennial Commentary in 2025

Presented is a short review of major novel introductions in dentistry in the 20th and 21st century. Discussed are advantages, and the impact from computers, automation, digitizing, robotics and artificial intelligence in the practice of dentistry.

Dentistry in the 19th century was primitive, in that most tooth aches were treated by exodontia and makeshift prosthetic replacement. A mechanical philosophy dominated dentistry. The germ-theory in the mid19th century explained that tooth decay started with chemical decalcification, and subsequent microbial action to produce dental caries. Physical removal of decay and replacement with inert material like pliable amalgams and gold developed. Tooth decay was common and ubiquitous, and dentists relied on hand- or foot-powered hand-drills to remove decay and was salvaged with confirmative amalgam fillings. In the late 19th and through most of the 20th century, … amalgams and ‘silicates’ had structural limits in application, and metal (mostly gold) inlays, onlays, overlays and crowns were made laboriously from direct wax impressions on prepared teeth. This was the ultimate zenith of restorative dentistry. Tooth replacement evolved from removable hand carved pieces of ivory and vulcanite prostheses. Auxiliary dental materials were slowly introduced using zinc-oxide and eugenol and phosphate cements. Impression materials were mainly alginate or plaster-of-paris. The question frequently asked in the last two decades of the 20th Century was:” What is the future of dentistry now that computers are here?” At that time few dental health care workers could answer with insight, confidence or from experience. Now over four decades later and well into the 21st century (2025), an experienced based informed response is due [1,2].

Aim

This is a short summary of major novel introductions in the practice of dentistry in the 20th and beginning of the 21st century, comments on advantages, and discussion of the impact of computerization, digitizing, robotics and artificial intelligence in the practice of dentistry.

Commentary on Innovations in Dentistry from 1900 to 1985

The metamorphosis from a mechanical replacement, to a biomedical model of thinking. Principles dictate policies and for the training, qualifying professionals and practicing dentists, dentistry became regarded as a subspecialty of medicine, with a mission to save natural teeth for life. Awareness of oral hard and soft tissue morbidity as manifesting signs of vital systemic disease, and the importance of oral health for systemic well being brought about a renaissance of therapy, specialization and public service. General dentistry, periodontics, orthodontics, maxillo-facial surgery, oral pathology and oral medicine all became power driven biomedical subspecialties of biologically based Medicine [1-3].

Use of stainless-steel for partial- prosthesis, arch-wire, banding and spot welding. Stainless steel replaced gold and orthodontics as a specialty flourished. Partial-prostheses constructed on chrome-cobalt skeletons, advanced removable prosthetic replacement [4,5].

X-rays: Radiography was introduced and decay detection, as well as bone assessments improved diagnosis and management. Roentgenography allowed 2-D visualization of calcified structures (teeth and bone mainly) with consequent ease of detecting early caries formation on teeth, and also maxilla-facial bone morbidities [6].

The Use of an Electric Motor Powering Hand-Held Drills

The electric motor with geared loops drove straight-, and right-angled hand-pieces from 5 to 6000 revolutions per minute. Cutting sharp steel drill-bits facilitated decay removal and cavity shaping. Standard electric motors were used to drive hand-held hand-pieces. These motors were engineered with internal gearings of the handpiece, to facilitates the mechanical fit of cutting burrs to rotate at constant speeds independent of torque. This replaced manual and foot drills allowing for quicker and more complex tooth-cavity preparation. But this still required strong manual/digital power for cavity-prep even though it was less tedious and slow [7].

The Use of Local Analgesic Injections

After World War-I (1914-1918) local- injection technique virtually replaced the use of nitrous oxide anesthesia and conscious sedation for operative dentistry. General anesthesia and controlled conscious sedation are now not the first choice for pain control with dental procedures. Local anesthetic injection paraphernalia (thin stainless-steel needles and carpules of liquid anesthetic solution) is now mass produced, presterilized and vacuum packed for one-time rapid use [8].

Introduction or Rubber Polymers and Silicone Rubbers for Impression Materials

This allowed for indirect very accurate impressions of prepared teeth and more extensive restorative dentistry. Tooth restorations like inlays, onlays, overlays, crowns and bridges, were developed in Dental mechanical laboratories. Development of polymer chemistry to produce acrylic plastic for denture bases and artificial tooth manufacture [9].

High-Speed Air-Driven Hand-Drills

Electric belt-driven drills managed a maximum of 5000 rpm; the aerotor spins at speeds over 90 000rpm, and markedly facilitated rapid, precise cavity and crown preparations. A trained gentle touch with far less power was needed to prepare teeth for restoration [10].

Potable Municipal Water Fluoridation to Prevent Tooth Decay

Eufluoride at 1part per million (1mg/Liter) reduces caries prevalence by up to 80percent. Fluoride that exceeds 1.2mg/L is deemed toxic and will affect calcification and discoloration of teeth and bones. The ill-informed politicized a movement of anti-fluoridation, who aver that any fluoride, at any concentration level is lethal or toxic. Although fluoride is made available in tooth pastes and in diets (with black Camellia sinensis Tea and in fish), the decay reduction effect is minimal when compared to integrated calcium-fluorhydroxyapatite into developing dentin and enamel. Eufluoridation in potable drinking water is the optimal way of ensuring resistance to dietary induced dental decalcification, and any consequent decay formation in stagnant biofilm sites [11,12].

Osseointegrated Implants

The successful use of stable osseointegrated implants, founded on basic research and scientific principles, significantly advanced replacement of missing teeth. A fixed stable, durable and healthy anchor in the jaws has permitted very advanced oral reconstructions for dental and maxilla-facial prostheses. Individual tooth replacement, to successful (form and function) full mouth oral rehabilitation of partial or total edentulism is now a reality [13].

Introduction of Etch and In Situ Polymerization of Resins

Pit and fissure sealants (Etch and Fetch)) as a caries prophylactic measure was soon followed by composite resin use for conformative and restorative dentistry. Cavity-prepared-teeth with acid-etching allows for physical and chemical bonding to teeth by monomer in situ polymerization and accelerates all therapy from conservative dentistry to orthodontic banding. Preparing teeth with etching and use of in situ polymerization allowed for more conservative retention of tooth material. While ‘extension for prevention’ was minimized, larger expanded areas of missing tooth-material could be restored with chemical and physical bonding on prepared teeth, with composite resins [14].

Advanced imaging techniques, were introduced. This improved visualization of hard and soft tissue, and has vastly ameliorated diagnosis, treatment planning and monitoring outcomes. Tools used like pan-oral peri-apical and radiography, specialized regional tomography, cone-beam radiography, echography ultra sound, CAT scans (Computer Assisted Tomography), magnetic resonance imagery (MRI), and fluoroscopic techniques are all imaging techniques used to assist in most branches of dentistry [15].

Archiving Dental Records

Most countries world-wide passed laws that dentists must keep records of any and all work done on patients.  Retaining times vary but most stipulate ten years as a minimum. This practice is widely used in forensics for positive identification of people alive and dead. Radiographs especially are used to identify ‘points of concordance’ in at least six or more of focal points for certainty. Properly fixed silver-based radiographs do not degenerate. However, digital computer radiographic images are easier to store and occupy far less space than radiographs on plastic [16,17].

Practice Management

Running a single-person dental practice was akin to administering a mini-hospital, with all the needs and demands for success pivoting onto the dentist. Among the many duties of staff, and practice the financing of the set-up demanded a different set of budgeting, accounting, book-keeping and economic skills. Professional record keeping, payment records and billing were all done by hand and aided by copying machines, ledger filing systems and small calculators. This was a necessary chore done individually by hand and human error is frequent with this labor intensive and tedious modus operandi.18

Enter the era of Precision Automation from 1985-2025

Computers as instruments are as old the Abacus in ancient times. With the development of electricity, digitization and miniaturization of computer chips and electric circuits, computers which started as machines as large as haulage-truck in 1960’s, have now become much smaller, from small foot-high towers, flat foldable tablet desk-tops, to small portable hand-held models. Screens are manufactured to size for purpose and can be as high and wide as a screen-room-wall, or as small as the area of a wrist-watch. Machines that computed calculations, retained data, and created images that were once science fiction, are now a scientific reality. Programed computers and robotic actions have impacted the practice of 21st Century dentistry. Complex computer programs have hatched to assist operators to expedite speed of data acquisition, recognition with listing differential diagnosis, and assisting in successful accurate therapies [1,2].

Robotics as Assistants in Dentistry: Direct Examples of Use of Computer Adjuncts in Dentistry

Clinical Examination: Computer assisted examination explorers and probes now automatically record data as caries, cracks, lor leaking margins. Electronic probes for periodontics and endodontics are available. See comments below.

Pathology and Histology: Pathology and hematology relies on microscopic examination of tissues and cells for accurate confirming diagnoses. Abnormal or atypical cellular shapes and morphology can be recognized; in hematology and histology mild, moderate or severe dysplasia, and deviant morphology or neoplastic changes are identified and recorded by robotic processes. Differential diagnosis of macroscopic images is now achievable with A.I. visual comparisons. Aided by computers, audio-spoken remarks when examining microscopic slides are immediately recorded and automatically printed out as written reports. Use of biochemical analytic techniques involving liquid chromatography, assist in diagnosing specific disease related models. Computers recognize and match diagnostic shapes to previous confirmed diagnostic patterns [19,20].

Periodontics: Pressure sensitive probes recording of examination data are used for baseline data facilitating diagnosis and planning. The probe will note and record the pocket depths, bleeding on probing and/or pus formation at multiple sites on every tooth examined.  This is an essential base used in most branches of dentistry. Comparison of current observations against passed recorded data reaffirms clinical selection of treatment and skills for accuracy and successful outcomes [21].

Endodontics: Cleaning and preparing root canals are perfected with simple electronic circuits. A programmed computer will aid by signaling when the soft tissue of the apex is reached with endodontic reamers [22].

Imagery: Programs now can scan old radiographs and indicate subtle changes. Diagnosis of decay, change in bone morphology, and any change of calcification can easily be detected. Patterns of bone loss will yield probable differential diagnosis of lesions or presumptive list of pathology. Fluorescent radiograms, assist with sialography and can be stored for examination. Once digitized all radiographic images may be sent to remote experts for second opinions. Nearly all digitized imagery apparatus is now computer linked. Introduction of digitization onto electronic screens, in preference to hardcopy developing on plastic screens, has revolutionized investigations, diagnosis and therapy [23].

Osseointegrated Implants: The advanced imaging systems digitize and programme for guided implant placement, with sub-millimetric accuracy.  A computer program will calculate the best implant specs available for the bone and space available [24].

Mechanical Processing and Dental Prosthetic Construction: Computerized measuring photography of prepared teeth, instructs a programmed robot machine to carve out the required restoration for the recipient tooth, like the Cerek system. Digitally-controlled prosthetic milling reduces human error, accelerates the process, and maximizes technician’s output. Because the processing time is reduced from weeks or days to hours, placement of temporary restorations is generally eliminated [25].

Orthodontics: Successful realignment of teeth depends on the rigidity and elasticity of stainless-steel wire, shaped by bending to the exact requirements to pressure teeth. Automated orthodontic wire bending facilitates appliance construction with clasps, levers and arches. As noted above, placement of brackets is accelerated with composite-resins, and digitally pre-shaped wire-arches expedites therapy and saves time [26].

Molecular Biology: Computers have been used to facilitate RNA/DNA intracellular biochemistry. The arrival of long non-coding RNAs (lncRNAs) is a major change in molecular biology. These large RNA molecules, with over 200 nucleotides, have regulation effects, inducing intra-cellular biochemical reactions with multiple interactions with proteins, DNA, and RNA. Research with host lncRNAs’ immunity functions, especially with infectious bacteria, reveal important biochemical mechanisms. This expanding research continues to clarify the biochemical pathways derived from lncRNA-mediated immunity. Host lncRNAs are central with bacterial infections, inducing cellular biochemical pathways to establish a strong immune defense. Understanding these biochemistry pathways is essential in advancing novel approaches to therapies against infectious diseases. This rapidly advancing research into lncRNAs is yielding novel aspects by infective bacteria, as it embraces effects on cellular damage, immune responses, host–pathogen/microbiome interactions, and drug resistance [27].

Genetics: Computerized robotics are used to map out genetic loci. Gene editing of human genomes using advanced techniques like CRISP, allows for identification and moderation of defective genes. Correcting Sickle cell anemia is one example. But genes controlling tooth-bud formation and maturation, may be identified in future, but currently remains obscure. Instructing genes to regenerate new tooth-buds to mature into specific teeth into desired positions is an aspiration for the future [28].

Pharmacology: Antibiotics and tranquilizers

Antibiotics were discovered in the 1920’s (Penicillin by Fleming) and its use in Medicine was prevalent after World War-II (1939-1945).  These drugs have a significant positive effect on curing infectious diseases that have potential mortality when not treated, like pneumonia and bacterial cellulitis. But because antibiotic use increased growth and weight in chickens (mainly), excess use and abuse led to antibiotic resistance, especially penicillin.  Methicillin resistant Streptococci, Staphylococci and Clostridium species, among others, are now common in society in general and in hospitals. Potential adverse effects as the risk of intestinal dysbiosis, and antimicrobial resistance may materialize. Also, allergies to penicillin mushroomed and in some populations allergies to penicillin can be as high as 10 percent. Consequently, alternates like macrolides, and antimicrobials (metronidazole and/or sulphonamides) are used to prevent or cure microbial morbidity in dentistry. These outcomes have constrained the use of antibiotics and aseptic techniques have improved for operations in dentistry, which are now more frequently done without antibiotic cover [29]. In dentistry, sedatives as tranquilizers, especially from the benzodiazepine group, are frequently prescribed to control patient anxiety; they produce sedation for all dental procedures that can be painful. Administering these drugs embrace oral, intravenous, and inhalation methods. Commonly used drugs include midazolam, diazepam, and nitrous oxide all of which are often used to assist patients to be calm, and cooperative, with far less stress during dental treatment [30].

The hands are a bio-mechanical execution apparatus activated by action potentials generated in the brain. Haptics is the science concerned with tactile sensations. Dentistry relies on manual skills and digital manipulations to fully control executing conceptual ideas with specialized ordinates that hands and the fingers cannot do. The fingers manipulate specialized instruments to desired specialized actions. From root plaining (removal of infected or affected dental material), drilling and shaping cavities, reaming out root-canals, to apical peaks, handling dental materials   or to precise surgical incisions, the hands act as haptically extensions of the brain in executing dental treatment. Automated robots can be programmed to assist in the proficiency, accuracy and reliability to perfect most of these actions. Robots won’t replace dentists but are restructuring the practice of dentistry.

Computers are robotic machines that accurately and reliably follow instructions. Robots are only as effective as the judgment that guides them. The great advantage of computers is that they never forget. However, malfunction is a real risk of losing data, and damage to memory discs is possible but rare. Contemporary dental and medical health care workers must familiarize themselves with computer use as tools to assist in accurately performing their duties, to optimize their talents and maximize productivity from their efforts. Esthetic dentistry which is durable and emulates idealized nature is evolving rapidly, but judgement calls from dentists for esthetic enhancement will always rely on the dentist’s personal discretionary choice, which will be influenced by education, training and culture. Automated robots’ range and limits are constrained by the expertise and judgement determined by the people who create them.

Computerized automated robots refine (with reliable memory and accurate repetition) but are constrained and will be refined and defined by known existing skills. Expertise in the profession of dentistry remains essentially human. Artificial Intelligence can provide some guidance in principles, but pragmatic practice remains in the controlling hands of executing dental health care workers.

Authors Statement

The author has no conflicting interests to declare.