The Pros-CAT protocol critical appraisal method uses accepted strategies to identify and summarize best evidence to support patient care through evidence-based analysis that includes assessing the patient; developing a concise clinical question; conducting a literature search to identify pertinent research; critically appraising the identified literature for validity, reliability, and applicability to the patient situation; synthesizing the literature into a meaningful conclusion using an organized method; and applying that synthesis to the patient’s need. The Pros-CAT protocol is applicable for practicing clinicians, dental students, postgraduate students, and residents. The Pros-CAT index compares evidence strength for patient applicability.
Key points
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A thorough patient assessment identifies clinical questions about prognostic factors that affect patient care outcomes.
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Clinical questions in the population, intervention, comparison, outcome format organize terms and assist the development of focused publication database searches.
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The Pros-CAT worksheets guide meaningful assessment of identified publications that are prognosis, therapy, harm, or systematic review formats.
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The Pros-CAT index compares identified articles validity and patient applicability in the context of the evidence hierarchy to determine the most relevant, highest quality information that answers the clinical question.
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Using the Pros-CAT protocol and index, clinicians are able to identify current, relevant, best evidence to answer patient care decisions.
Introduction
Patient-centered decision making is the principle on which successful treatment plans are developed. Patients seek predictable, state-of-the-art solutions for their concerns with goals of health promotion, disease prevention, disability recognition, and rehabilitation with a decreased incidence of maintenance and complications. Clinicians must have full awareness of patient expectations regardless of the therapeutic intervention. Clinicians must integrate patient expectations with clinical experience and the available published knowledge regarding a multitude of prognostic factors. These fundamentals are essential for patient-centered decision making and care.
A clinician’s knowledge must continuously grow as the dental profession’s knowledge expands. Evidence-based decision making is described as the conscientious, explicit, and judicious use of the current best evidence in making decisions about the care of individual patients. Contemporary dental practice is therefore founded on treatment decisions supported by a meaningful synthesis of the current clinical research. Health care professionals risk antiquated practice when their knowledge growth is less than that of the profession as a whole.
A straightforward, patient focused, critically appraised topic (CAT) method for literature appraisal was named Pros-CAT because it evolved within the accredited University of Illinois at Chicago Advanced Education Program in Prosthodontics, and for recognition that the method originated from the prosthodontic community. The format was developed following the Journal of Prosthetic Dentistry Evidence-Based Dentistry article series. The series was written by 10 prosthodontists who visited McMaster University Medical School in the early 1990s to learn the decision-making process developed by Dr David Sackett, who is known as the father of evidence-based medicine. As a nephrologist and epidemiologist, Dr Sackett applied his skills in epidemiology and biostatistics in appraising the quality and validity of evidence for patient application, thereby setting the stage for structured appraisal in prosthodontics and dentistry as a whole.
The Pros-CAT approach has meaningful application for clinical decision making. Considering patient presentation and care goals, specific prognostic factors that relate to clinical concerns are recognized, and concise clinical questions for treatment decisions are developed. Clinicians can have confidence when applying current best information identified with skills in literature analysis and synthesis. After the pertinent clinical literature is identified and appraised, the publications of greatest merit are synthesized into meaningful and brief topic summaries for immediate clinical application. The goal is to improve care outcomes when clinicians are empowered by an organized approach that guides patient-centered decisions.
Beginning with the development of the clinical question, 2 straightforward dental implant patient scenarios will be presented to provide examples for using the Pros-CAT protocol:
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Scenario 1: Immediate Implant Placement, Immediate Restoration, and Esthetics; and
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Scenario 2: Implant Fixed Complete Denture Prostheses and Veneer Fracture Incidence.
Assessing the patient
The goal of patient assessment is to maximize success and minimize the risk of complications by first identifying relevant prognostic factors. Patient medical and dental history, signs, symptoms, and diagnoses are examples of prognostic factors that must be recorded accurately to identify care outcomes. For example, prosthodontists consider the implications of many factors in the decision of prosthesis design, support, and esthetics. Depending on patient need and care considerations, the medical history, patient ability to tolerate surgical procedures, dental condition, caries risk, history of periodontitis, and bruxism are only a few of the many factors that could affect care outcome. Incomplete information can compromise care results.
The effects of prognostic factors individually and in combination on short- and long-term dental implant prognosis are difficult to determine. Indicated prosthodontic care options, which meet patient esthetic and functional expectations, determine predictable prosthesis design, prosthesis support, and decisions for adjunctive care. Melding of objective clinical findings with patient concerns leads to the initial care goal, for example, fixed or removable prosthesis designs. Patient presentation, patient expectations, and determined prosthesis design guide required prosthetic support, for example, tooth, implant or oral mucosa. Each support type leads to different prognostic factor considerations, for example, periodontal history, bone quantity and quality, and the presence of keratinized tissue. The influence of these factors is complex, because each patient has unique medical and dental status, treatment expectations, prosthesis design considerations, and long-term maintenance needs.
For patient-centered decision making, the careful assessment and identification of prognostic factors leads the clinician into a concise, answerable clinical question that directly applies to a specific patient’s needs and expectations. Favorable or less favorable outcomes may be identified when such goals and factors are investigated in depth in the literature. Well-defined questions developed from correctly identified prognostic factors lead to the identification of patient-relevant literature and confidence in clinical decisions.
Developing the clinical question
Clinical questions can be developed in the straightforward population, intervention, comparison, outcome (PICO) format described by Sackett and colleagues. The PICO format describes the patient population in question. The intervention is the considered patient or prosthesis factor that could influence therapy. The comparison is the factor that may lead to a different therapy result, and the outcome is the specific therapy result of interest. Patient-specific prognostic factors are carefully related to these areas to define publication database search terms leading to a meaningful literature search. Concise PICO components lead to a well-defined database search and the best evidence for decision making.
Population
The population is the group of patients found in published clinical research that best describes an individual patient who will receive care. A clear description of the patient is the first critical step in developing an effective literature search, because the population later identified in the researched literature directly arises from the patient’s need. The conclusion from the investigation and critical appraisal then directly applies. Literature application for patient-centered relevant decision making brings greatest clinical meaning to the process.
A description of the patient population is infinitely broad and limited only by the clinician’s imagination and the clinical question’s applicability to the patient. Descriptions could include but are not limited to the surgical therapy they received, the specific prosthesis type, or the complications they developed. For example, the population might be described as (1) patients desiring dental implant therapy, (2) patients with mandibular dental implant overdentures, or (3) patients with periimplantitis. A clear definition of this population with carefully designed descriptors limits the literature search and identifies the articles most applicable to the patient about whom the question is generated.
Intervention and Comparison
The intervention is the potential prognostic factor or therapy approach that could directly affect the treatment results. Interventions could include but are not limited to medical history factors, clinical observations about the patient, prosthesis design factors, or proposed adjunctive therapy. As an example, for any patient receiving dental implants, interventions could include a (1) history of diabetes, (2) severe maxillary residual ridge resorption, (3) number of implants used in prosthesis design, or (4) the use of maxillary sinus augmentation. For any patient, each factor could predict care results.
The comparison describes the alternative patient descriptor or therapy approach that represents a potential pathway to a different therapeutic result. For example, with implant prognosis in the posterior maxilla, an intervention of long implants could be compared with short implants. If one is concerned with patient satisfaction based on therapy, a second intervention and comparison example could be single implant therapy compared with 3-unit, tooth-supported fixed partial denture therapy. Regarding periimplant bone loss, an intervention and comparison might be presence of periimplant keratinized tissue compared with a lack of keratinized tissue.
In the PICO question, the intervention and comparison concisely describe factors the clinician finds particularly important for treatment decisions. These suspected factors may influence the therapeutic outcomes.
Outcome
The outcome identifies a potential treatment result. Outcomes were described in 4 major categories, including (1) longevity, (2) physiologic, (3) psychological, and (4) economic outcomes. An additional update from Carr and colleagues 2011 provided further category clarity. Each outcome group can be further divided into subcategories ( Table 1 ). Within each category and subcategory, many prognostic factors with influence on outcome can be imagined. Table 2 presents a small sample of the outcomes and possible prognostic factors associated with dental implant survival. Each prognostic factor suggests possible interventions or comparisons that affect outcomes.
| Longevity | Functional | Psychological | Economic |
|---|---|---|---|
| Maintenance/follow-up | Speech | Treatment satisfaction | Direct costs |
| Implant survival | Swallowing | Self-image/confidence | Indirect costs |
| Implant success | Mastication | Esthetics | Disparities in health care |
| Prosthesis complications | Nutrition | Perception of function | Third-party policies |
| Prosthesis success | Motor/sensory function | Treatment preference | |
| Time to retreat | Health-related QoL | ||
| Overall QoL | |||
| Food preferences |
| Longevity/Survival | Outcome Categories | Prognostic Factor Categories | Example Prognostic Factors |
|---|---|---|---|
| Implant level | Implant success Implant survival |
Systemic health Oral health Implant site Implant design Timing for prosthetic restoration Oral habits |
Chemotherapy Periodontitis Bone quantity Bone quality Bone graft Implant length Implant diameter Implant surface Implant angulation Occlusion Bruxism |
The outcome describes one discreet aspect of patient therapy and does not represent the overall treatment result. For patients a mandibular implant supported fixed-complete prosthesis, the implant survival, prosthesis survival, occlusal force, nutritional intake, and patient satisfaction with esthetics or function each contribute to care success. Weighing the importance of these outcomes for an individual patient following literature appraisal is the defining action of the Pros-CAT analysis strategy. With these definitive clinical questions, a well-guided literature search focused on applicable prognostic factors can follow.
Assembling the Population, Intervention, Comparison, Outcome Question
Clear decision making results from a concise identification of the applicable prognostic factors and outcomes. The PICO question is assembled from the defined population, intervention, comparison, and outcome. The following clinical scenarios provide relevant examples for developing meaningful questions.
Scenario 1: Immediate implant placement, immediate restoration, and esthetics
A 35-year-old, partially edentulous patient desires a single implant to replace a maxillary central incisor. She requests immediate implant placement after extraction to expedite therapy, and she is focused on favorable esthetics throughout the care process. A thorough clinical evaluation suggests adequate alveolar bone and soft tissue quality exist to achieve favorable initial esthetics with immediate placement and immediate restoration. Decisions for the use of an immediate restoration compared with a more conventional, delayed approach are of interest. Stability of the periimplant soft tissue height is in question as it directly relates to prosthesis emergence, single implant crown dimensions, and the short- and long-term esthetic results.
For scenario 1, the PICO components are: P = patients with single maxillary incisor implants who desire immediate implant placement; I = immediate provisionalization; C = delayed provisionalization; and O = esthetics as determined by periimplant soft tissue dimensional change. The assembled PICO question is, “For patients who desire single maxillary incisor implant immediate placement, does immediate restoration compared with delayed restoration affect the esthetics as measured by soft tissue stability?” Implant survival is assumed with this question. Additional prognostic factors must be considered, such as bone volume and quality, soft tissue phenotype, immediate implant stability, immediate implant survival, and occlusal considerations. The risk of immediate implant failure or complications may be greater. Each of these relevant factors would be given full consideration during decision making when exploring immediate implant placement and restoration by constructing specific PICO questions.
Scenario 2: Implant fixed complete denture prostheses and complications incidence
A 50-year-old, edentulous patient is dissatisfied with the esthetics and function of her maxillary complete denture and mandibular implant-supported fixed complete denture she has worn for 5 years. Occlusal wear occurred with both prostheses, and her mandibular prosthesis has had frequent lost teeth and veneer fractures. Mandibular implants have no bone loss or periimplant inflammation. Consideration for care includes replacement of the existing prostheses. Further consideration includes additional implants in the maxilla for an opposing fixed complete prosthesis. Zirconia prostheses are an option, but further investigation is necessary to determine the incidence of complications with zirconia and veneered zirconia compared with other designs.
Based on this scenario, the PICO components could be: P = edentulous patients with implant-supported fixed complete denture prostheses; I = zirconia prostheses; C = resin-metal prostheses; and O = complications. The assembled PICO question would be: “For edentulous patients who desire implant supported fixed complete denture prostheses, do zirconia prostheses compared with resin-metal prostheses have different incidence of complications?” Many relevant patient factors can be considered. For example, this question does not define the potential incidence of complications as influenced by opposing prosthesis designs and material. When comparing opposing complete denture, a resin-metal fixed complete denture, or a zirconia fixed complete denture option, bite force and supporting structure compliance (soft tissue vs implant) may influence the rate of occlusal wear and prosthesis fracture. Additional concise questions are necessary to identify trends such as these in greater detail.
Conducting the literature search
Only clinical research literature specifically applicable to the PICO question is of value in answering a clinical question. Consider the patient in scenario 1 with immediate implant placement after maxillary incisor extraction. One must search for only those articles that report esthetics as determined by measurable soft tissue height and discount those that report survival for other sites. Other prosthesis designs are not considered, because prosthesis design, loading conditions, maintenance, and complications could be quite different in those studies. Only when no relevant information evidence is identified can parallel literature with disparate patient characteristics or prosthesis designs be related to the question with understanding that the results do not directly apply.
A literature search is conducted through electronic and hand searching methods. Well-recognized and reliable databases exist including the Cochrane Library, TRIP, PubMed, EMBASE, and Web of Science. Each has their individual strengths based on purpose. PubMed and EMBASE are a broad access starting point for literature, whereas the Cochrane Library and TRIP focuses on high-quality evidence in different ways. Not all evidence is indexed in all databases. Access to more than 1 database may be necessarily followed by hand searching for thorough literature search identification.
Specific terms are used to categorize articles in the National Library of Medicine MEDLINE database. Search engines such as PubMed are helpful in finding the primary references of interest. Population, intervention, comparison, and outcome search terms can be identified using Medical Subject Headings (MeSH) directly related to PICO by entering a relevant term in the search field. For example, if one searches dental implant, the search engine will identify MeSH headings of (1) dental implants, (2) dental implantation, (3) dental implants, single-tooth, (4) dental implant-abutment design, (5) immediate dental implant loading, and (6) dental prosthesis, implant supported. These are patient population descriptors. Similar searches can be completed for the intervention, comparison, and outcome groups. When all terms are identified through the MeSH heading search, Boolean operators (AND, OR, or NOT) can be used to best develop the search strategy. During the search, limits are imposed for clinical trial, randomized controlled trial, metaanalysis, and systematic review references to find the reference of greatest strength and applicability. After this search, additional electronic and hand searching methods can be used.
Clinicians must have access to published literature. Online periodic subscriptions are available, and these accounts can be used to maintain the clinician’s current practice standard. Single pay-per-view articles can provide access to the most relevant information in decision making in a broad range of periodicals most feasible. The cost for access to this information could be considered a necessary expense for contemporary practice and care.
The search focus is to identify systematic review and metaanalyses, followed by randomized controlled trials, clinical trials, and clinical studies. Straightforward searches arising from MeSH headings are likely to identify critical publications. Searches described in systematic reviews may help to develop additional search terms and searches that relate to the clinical question. Many searches may be required to identify the highest quality available evidence.
The following searches are examples that arise from a PICO question. Search strategy format must be consistent with search engine principles. For example, search field descriptors and tags can be added with PubMed to further focus the search. Scenario 2 applies as a mechanism to identify search terms within a publication’s title or abstract. The search focus is to preferably identify systematic reviews and higher order evidence, followed by evidence lower in the hierarchy.
Scenario 1: Immediate Implant Placement, Immediate Restoration, and Esthetics
Search terms for immediate implant placement and loading are assembled for the PubMed search limited for systematic reviews are (“Immediate Dental Implant Loading”[Mesh]) AND (“Esthetics, Dental”[Mesh]).
Scenario 2: Implant Fixed Complete Denture Prostheses and Veneer Fracture Incidence
Terms for the PubMed search limited for systematic reviews are (“zirconia”[tiab] OR “methacrylate”[All Fields] OR “polymethyl methacrylate”[All Fields] OR metal-resin[All Fields] OR metal-acrylic[All Fields]) AND (“dental implant”[tiab] OR “Dental Implants”[Mesh] OR “Dental Prosthesis, Implant-Supported”[Mesh] OR “Dental Prosthesis”[Mesh] OR “implant-supported”[tiab] OR “full arch restorations”[tiab] OR “full arch restoration”[tiab] OR “complete-arch”[tiab]). A modified search not limited to systematic reviews includes zirconia AND (“methacrylate”[All Fields] OR “polymethyl methacrylate”[All Fields] OR metal-resin[All Fields] OR metal-acrylic[All Fields]) AND (“dental implant”[tiab] OR “Dental Implants”[Mesh] OR “Dental Prosthesis, Implant-Supported”[Mesh] OR “Dental Prosthesis”[Mesh] OR “implant-supported”[tiab] OR “full arch restorations”[tiab] OR “full arch restoration”[tiab] OR “complete-arch”[tiab]). A portion of this search strategy was previously described.
Critically appraising the literature
The highest form of available evidence must be applied to the PICO question. Evidence is evaluated for validity and patient applicability, and the best evidence supports focused clinical decision making for each patient.
Identifying the Best Evidence
Literature is assessed based on its strength in research design ( Table 3 ). Expert opinion and personal clinical experience are the lowest forms of evidence. Stronger evidence includes clinical research of various designs, with the randomized controlled trials having greater strength. The true systematic review in which several randomized, controlled trials are selected based on specific, well-planned inclusion factors is higher on the clinical evidence pyramid. Cochrane Collaboration Study Groups have generated in-depth systematic reviews on a variety of topics in many areas of medicine and dentistry. The Cochrane reviews are considered higher order evidence because they strictly apply prospective randomized controlled trials for reviews.
A 6S hierarchy of evidence was introduced in 2009 as the publication of critical appraisal articles grew. The 6S model includes single studies, syntheses (structured systematic reviews), synopses (short critical analyses of studies or systematic reviews), summaries (assimilation of best evidence from lower evidence to form clinical practice guidelines), and systems (computer-automated focused analyses of prognostic factors and outcomes for a specific patient). These are included in Table 3 .
Clinicians regularly apply recently published prospective or retrospective designs that are not included in advanced metaanalyses or higher level reviews, although according to the 6S hierarchy individual original articles are low on the hierarchy. Traditional recognition of the publication hierarchy prefers as example, prospective randomized controlled trials with well-defined patient populations, well-controlled prognostic factors, and adequate patient follow-up. Such studies are difficult to control, require possibly years of long-term follow-up, and are expensive. For these reasons, cohort, case control, and case series designs may be suitable to answer patient-centered questions.
Prognosis, therapy, harm, and overview article analyses are frequently used to predict if a patient prognostic factor or care intervention might influence the care outcome. Incorrect article designation leads to an irrelevant critical analysis. Recognition of the correct article design is necessary for analysis of research validity and applicability. Sackett’s primer and the Journal of Prosthetic Dentistry series are sample references.
Study design and outcome type designate the format for critical appraisal. Prognosis articles are generally associated with prospective or retrospective cohort or case control studies. Therapy articles present comparative care within 1 study using 2 similar, well-identified patient populations, and these studies are ideally represented with prospective, randomized, controlled trials. Harm articles present comparative outcomes and may be presented in randomized, controlled trials, cohort studies, case control studies, and case series. Overview articles, or metaanalysis and systematic review articles, seek to provide a well-controlled assimilation of lower level studies that present similar data and outcomes. The study design and outcome type determine the assessment criteria for research validity and patient applicability. Incorrect article designation leads to an irrelevant critical analysis.
Research Validity
Tables 4–7 present focused question matrices that arise from the Journal of Prosthetic Dentistry series to assesses validity for prognosis, therapy, harm or overview articles. More favorable answers imply potentially greater perceived evidence strength. For example, with prognosis or therapy articles, a greater number of favorable answers in all categories are consistent with a well-designed randomized, controlled trial, high-level evidence among individual studies. Information from lower level studies (case series, cohort studies, case control studies) may also be useful when 10% to 50% of the answers to the worksheet questions are affirmative. Fewer affirmative answers are a commentary on the difficulty in completing a well-controlled, long-term trial, but studies lower in the hierarchy may still be relevant and valuable for the patient under consideration.
