Implant Treatment in the Predoctoral Clinic: A Retrospective Database Study of 1091 Patients.

PURPOSE: This retrospective study was conducted at the Marquette University School of Dentistry to (1) characterize the implant patient population in a predoctoral clinic, (2) describe the implants inserted, and (3) provide information on implant failures. MATERIALS AND METHODS: The study cohort included 1091 patients who received 1918 dental implants between 2004 and 2012, and had their implants restored by a crown or a fixed dental prosthesis. Data were collected from patient records, entered in a database, and summarized in tables and figures. Contingency tables were prepared and analyzed by a chi-squared test. The cumulative survival probability of implants was described using a Kaplan-Meier survival curve. Univariate and multivariate frailty Cox regression models for clustered observations were computed to identify factors associated with implant failure. RESULTS: Mean patient age (±1 SD) at implantation was 59.7 ± 15.3 years; 53.9% of patients were females, 73.5% were Caucasians. Noble Biocare was the most frequently used implant brand (65.0%). Most implants had a regular-size diameter (59.3%). More implants were inserted in posterior (79.0%) than in anterior jaw regions. Mandibular posterior was the most frequently restored site (43%); 87.8% of implants were restored using single implant crowns. The overall implant-based cumulative survival rate was 96.4%. The patient-based implant survival rate was 94.6%. Implant failure risk was greater among patients than within patients (p < 0.05). Age (>65 years; hazard ratio [HR] = 3.2, p = 0.02), implant staging (two-stage; HR = 4.0, p < 0.001), and implant diameter (wide; HR = 0.4, p = 0.04) were statistically associated with implant failure. CONCLUSIONS: Treatment with dental implants in a supervised predoctoral clinic environment resulted in survival rates similar to published results obtained in private practice or research clinics. Older age and implant staging increased failure risk, while the selection of a wide implant diameter was associated with a lower failure risk.

Defining periodontal health.

Assessment of the periodontium has relied exclusively on a variety of physical measurements (e.g., attachment level, probing depth, bone loss, mobility, recession, degree of inflammation, etc.) in relation to various case definitions of periodontal disease. Periodontal health was often an afterthought and was simply defined as the absence of the signs and symptoms of a periodontal disease. Accordingly, these strict and sometimes disparate definitions of periodontal disease have resulted in an idealistic requirement of a pristine periodontium for periodontal health, which makes us all diseased in one way or another. Furthermore, the consequence of not having a realistic definition of health has resulted in potentially questionable recommendations. The aim of this manuscript was to assess the biological, environmental, sociological, economic, educational and psychological relationships that are germane to constructing a paradigm that defines periodontal health using a modified wellness model. The paradigm includes four cardinal characteristics, i.e., 1) a functional dentition, 2) the painless function of a dentition, 3) the stability of the periodontal attachment apparatus, and 4) the psychological and social well-being of the individual. Finally, strategies and policies that advocate periodontal health were appraised.

Principles of periodontology.

Periodontal diseases are among the most common diseases affecting humans. Dental biofilm is a contributor to the etiology of most periodontal diseases. It is also widely accepted that immunological and inflammatory responses to biofilm components are manifested by signs and symptoms of periodontal disease. The outcome of such interaction is modulated by risk factors (modifiers), either inherent (genetic) or acquired (environmental), significantly affecting the initiation and progression of different periodontal disease phenotypes. While definitive genetic determinants responsible for either susceptibility or resistance to periodontal disease have yet to be identified, many factors affecting the pathogenesis have been described, including smoking, diabetes, obesity, medications, and nutrition. Currently, periodontal diseases are classified based upon clinical disease traits using radiographs and clinical examination. Advances in genomics, molecular biology, and personalized medicine may result in new guidelines for unambiguous disease definition and diagnosis in the future. Recent studies have implied relationships between periodontal diseases and systemic conditions. Answering critical questions regarding host-parasite interactions in periodontal diseases may provide new insight in the pathogenesis of other biomedical disorders. Therapeutic efforts have focused on the microbial nature of the infection, as active treatment centers on biofilm disruption by non-surgical mechanical debridement with antimicrobial and sometimes anti-inflammatory adjuncts. The surgical treatment aims at gaining access to periodontal lesions and correcting unfavorable gingival/osseous contours to achieve a periodontal architecture that will provide for more effective oral hygiene and periodontal maintenance. In addition, advances in tissue engineering have provided innovative means to regenerate/repair periodontal defects, based upon principles of guided tissue regeneration and utilization of growth factors/biologic mediators. To maintain periodontal stability, these treatments need to be supplemented with long-term maintenance (supportive periodontal therapy) programs.

Analysis of four dental alloys following torch/centrifugal and induction/ vacuum-pressure casting procedures.

STATEMENT OF PROBLEM: Previous studies have shown casting methodology to influence the as-cast properties of dental casting alloys. It is important to consider clinically important mechanical properties so that the influence of casting can be clarified. PURPOSE: The purpose of this study was to evaluate how torch/centrifugal and inductively cast and vacuum-pressure casting machines may affect the castability, microhardness, chemical composition, and microstructure of 2 high noble, 1 noble, and 1 base metal dental casting alloys. MATERIAL AND METHODS: Two commonly used methods for casting were selected for comparison: torch/centrifugal casting and inductively heated/ vacuum-pressure casting. One hundred and twenty castability patterns were fabricated and divided into 8 groups. Four groups were torch/centrifugally cast in Olympia (O), Jelenko O (JO), Genesis II (G), and Liberty (L) alloys. Similarly, 4 groups were cast in O, JO, G, and L by an inductively induction/vacuum-pressure casting machine. Each specimen was evaluated for casting completeness to determine a castability value, while porosity was determined by standard x-ray techniques. Each group was metallographically prepared for further evaluation that included chemical composition, Vickers microhardness, and grain analysis of microstructure. Two-way ANOVA was used to determine significant differences among the main effects. Statistically significant effects were examined further with the Tukey HSD procedure for multiple comparisons. Data obtained from the castability experiments were non-normal and the variances were unequal. They were analyzed statistically with the Kruskal-Wallis rank sum test. Significant results were further investigated statistically with the Steel-Dwass method for multiple comparisons (α=.05). RESULTS: The alloy type had a significant effect on surface microhardness (P<.001). In contrast, the technique used for casting did not affect the microhardness of the test specimen (P=.465). Similarly, the interaction between the alloy and casting technique was not significant (P=.119). A high level of castability (98.5% on average) was achieved overall. The frequency of casting failures as a function of alloy type and casting method was determined. Failure was defined as a castability index score of <100%. Three of 28 possible comparisons between alloy and casting combinations were statistically significant. The results suggested that casting technique affects the castability index of alloys. Radiographic analysis detected large porosities in regions near the edge of the castability pattern and infrequently adjacent to noncast segments. All castings acquired traces of elements found in the casting crucibles. The grain size for each dental casting alloy was generally finer for specimens produced by the induction/vacuum-pressure method. The difference was substantial for JO and L. CONCLUSIONS: This study demonstrated a relation between casting techniques and some physical properties of metal ceramic casting alloys.

Examiner alignment and assessment in clinical periodontal research.

Periodontal research typically relies on clinical examiners to assess variables such as gingival inflammation, plaque scores or probing depths as a means of determining treatment outcomes or for performing group comparisons. The quality of the gathered information is dependent, to a large extent, on the skills of the examiner(s) and on the validity of the assessment methods that are used. Attempts have been made to increase the objectivity of periodontal assessments, for example by introducing scoring systems for gingival inflammation, but within these systems there is often considerable scope for variation when interpreting the scoring criteria, leading to subjectivity when assigning scores to individual periodontal sites. This has led to an awareness of the importance of examiner alignment and assessment to improve the data quality by standardizing techniques and improving examiner reliability. Examiner alignment and assessment is used in preference to the term 'examiner calibration' because calibration implies comparison with an accurate or 'gold' standard, which is not available in periodontal research. In this review, we consider the historical perspective that led to the development of clinical scoring systems for periodontal research using gingival inflammation as an example. A clinical protocol for undertaking examiner alignment and assessment is presented, and we review the common sources of error and bias that can lead to difficulties in aligning examiners, and consider how they can be eliminated. It is particularly important that subjects who are recruited to the examiner alignment and assessment study present with a comparable level of disease to the subjects who will ultimately be recruited to the planned clinical trial. Another challenge in examiner alignment and assessment is applying appropriate statistical tests to assess the outcome of the alignment exercise. In the periodontal literature, the statistic kappa is frequently used to confirm an adequate degree of examiner agreement, but kappa is bound to significant restrictions when applied for this purpose. Through the use of case studies, we present different approaches to data analysis from calibration studies, focusing on continuous variables (such as probing depths and attachment levels) or ordinal data (such as gingival or plaque indices), to enable a correct, although frequently conservative, interpretation of data generated during examiner alignment and assessment studies.

Bonding with self-etching primers--pumice or pre-etch? An in vitro study.

The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (± 1 SD) for groups 1-4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs.

Moving an incisor across the midline: a treatment alternative in an adolescent patient.

A 13-year-old sought treatment for a severely compromised maxillary left central incisor and an impacted fully developed left canine. Extraction of both teeth became necessary. As the key component of the revised comprehensive treatment plan, the right maxillary central incisor was moved into the position of the left central incisor. All other maxillary teeth were moved mesially to close any gaps. Active orthodontic treatment was completed after 34 months. Frenectomy, minor periodontal surgeries, and bonded lingual retainers were used to improve aesthetics and stabilize the tooth positions. The patient was pleased with the treatment outcome. Cone-beam computed tomography provided evidence that the tooth movement was accompanied by a deviation of the most anterior portion of the median palatine suture. This observation may make relapse more likely if long-term retention cannot be ensured. Root resorption was not observed as a consequence of the major tooth movement.

Total protein concentration and total bacterial load as measures of residual interproximal plaque in comparative clinical trials.

AIM: Establish total protein concentration and total bacterial load as quantitative measures of residual interproximal plaque (IPP) in a clinical model designed to evaluate oral hygiene interventions. MATERIAL AND METHODS: This clinical model was a randomized, examiner and laboratory technician-blinded, parallel-design study whereby levels of residual IPP were compared for subjects using a manual toothbrush or a toothbrush+floss. Differences between interventions were compared after 7 and 21 days of use. Protein concentration was measured using 3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde in a fluorescence microplate format and bacterial load was assessed by quantitative real-time PCR with universal primers specific for 16S rRNA and detected by SYBR Green. ancova was used to assess the statistical significance of the differences between interventions while clinical relevance was evaluated by a statistical model described by Man-Son-Hing et al. 2002. RESULTS: Ninety-three subjects completed the study. Significant differences between interventions, using both outcome measures, were observed after 7 and 21 days. The difference between interventions by total protein concentration were further determined to be clinically relevant. CONCLUSIONS: Only total protein concentration provided both statistically significant and clinically relevant differences between two clinically distinct oral hygiene interventions in this clinical model for evaluating IPP.

A randomized, parallel design study to evaluate the effects of a Sonicare and a manual toothbrush on plaque and gingivitis.

OBJECTIVE: This study was designed to determine the effects of twice daily tooth brushing with the Sonicare Elite (Elite) and the Oral-B P40 manual toothbrush (MTB) on plaque accumulation and plaque-induced gingival inflammation. METHODS: One-hundred and eighty (180) subjects, with moderate gingival inflammation and a Silness and Löe Plaque Index (PI) of > or = 0.8 after refraining from oral hygiene for three to six hours, were randomly assigned to receive the Elite or MTB in this single-blinded, controlled clinical trial. At baseline and after two and four weeks of using the product at home twice daily for two minutes, efficacy was assessed with the PI and the Löe and Silness Gingival Index (GI) after brushing three to six hours prior to assessment The primary efficacy variable was reduction of baseline plaque scores over the four weeks for Elite compared to MTB. Secondary outcomes included a change in GI and number of bleeding sites. Safety was appraised using adverse event reports and soft tissue examinations. RESULTS: One-hundred and sixty-eight subjects (81 Elite, 87 MTB) completed the study. The four-week study period resulted in significant reductions of PI and GI from baseline at weeks two and four for both brushes. Reduction in mean PI from baseline to week four for Elite was 0.84 (95% CI: 0.80, 0.88), and 0.72 (0.68, 0.76) for MTB, p < 0.0001. Reduction in mean GI from baseline to four weeks for Elite was 0.56 (0.53, 0.59), and 0.47 (0.45, 0.50) for MTB, p = 0.0001. Both treatment groups demonstrated a significant reduction in number of bleeding sites relative to baseline (p < 0.0001); however, a significant difference in percent reduction in favor of Elite relative to MTB was found at week four: 82.5% vs. 75.8% (p = 0.026). Both toothbrushes were safe on oral tissues. CONCLUSION: Elite was significantly more effective than MTB in the reduction of plaque after two and four weeks of product use, and significantly more effective in the reduction of gingivitis and bleeding sites than MTB after four weeks.

Persistently high levels of periodontal pathogens associated with preterm pregnancy outcome.

BACKGROUND: Few studies examining the association between periodontal diseases and preterm birth have explored the underlying microbial and antibody responses associated with oral infection. METHODS: A nested case-control study was performed using data from a recent interventional trial following the delayed-treatment control group of 31 subjects with periodontal diseases. The levels of eight oral bacteria and the maternal immunoglobulin G (IgG) responses in serum to these bacteria were measured at antepartum and postpartum visits to determine the relationship to cases (preterm delivery <37 weeks' gestation) and controls (term delivery). RESULTS: Antepartum, the levels of periodontal pathogens tended to be higher in the preterm (case group) deliveries compared to the term deliveries (control group). Maternal anti-Porphyromonas gingivalis IgG was significantly lower in the preterm group compared to the term group (P = 0.028). Postpartum, levels of P. gingivalis, Tannerella forsythia, Prevotella intermedia, and Prevotella nigrescens were statistically significantly higher in preterm births compared to term deliveries, adjusting for baseline levels. The joint effects of red and orange microbial clusters were significantly higher in the preterm group compared to the term group. CONCLUSIONS: High levels of periodontal pathogens and low maternal IgG antibody response to periodontal bacteria during pregnancy are associated with an increased risk for preterm delivery. Further studies elucidating the role of the microbial load and maternal immune response as related to pregnancy outcome seem merited.

Using a Delphi panel to survey criteria for successful periodontal therapy in posterior teeth.

BACKGROUND: Health care providers have focused on outcome measures to determine the success or failure of treatment. In periodontics, there is no consistent view regarding what outcome measure(s) is(are) important for successful treatment. This study used a Delphi surveying technique to determine which outcome measures were clinically relevant to an expert panel of periodontists. METHODS: The Delphi surveyed 35 periodontists from the United States to determine the level of importance of attachment level, probing depth, furcation involvement, mobility, plaque, inflammation, esthetics, pain, and patient satisfaction following periodontal treatment of posterior teeth in a patient with severe chronic periodontitis. The Delphi panelists were questioned concerning the relative importance of each outcome measure, a minimally acceptable level considered necessary for success for each outcome measure, and the length of time required for these outcome measures to remain stable. RESULTS: Following two rounds of Delphi surveys, the panelists considered the control of pain to be an "extremely important" outcome measure for successful periodontal treatment. Attachment levels, probing depths, plaque levels, degree of inflammation, function, furcation involvement, and patient satisfaction were considered to be "very important" outcomes for successful periodontal treatment. The minimally acceptable reduction in probing depths following 1 year of treatment was 2 mm; whereas up to 1 mm of attachment loss was considered acceptable. The panel found that Glickman grade 2 furcation involvement or Miller degree II mobility would be considered an acceptable outcome for clinical success. Finally, the panel agreed that the 1-year results of treatment should remain stable for a minimum of 5 years. CONCLUSIONS: The Delphi surveying technique proved useful in developing a hierarchy for the relevance of periodontal outcome measures. Absence of pain was the only outcome measure considered to be "extremely important" for successful therapy. Although panelists considered attachment loss, furcation invasions, and mobility as "very important" outcomes, they were willing to accept loss of attachment of up to 1 mm, grade 2 furcation involvement, and degree II mobility following treatment as long as outcomes remained stable for 5 years. These data suggest that minimal standards for success of posterior teeth can be established among periodontal practitioners.

Using a Delphi panel to survey criteria for successful periodontal therapy in anterior teeth.

BACKGROUND: Valuable decision making for periodontal treatment success in situations where there is ambiguous or conflicting information was previously reported using a consensus building method, the Delphi survey, for posterior teeth with chronic periodontitis. This study focuses on outcome measures relevant in assessing therapy of anterior teeth with chronic periodontitis. METHODS: The Delphi panelists were the same American periodontists who participated in the previous Delphi survey evaluating successful therapy in posterior teeth. In this study, panelists determined the level of importance of attachment level, probing depth, mobility, plaque, inflammation, esthetics, pain, and patient satisfaction following periodontal treatment of a single tooth or multiple anterior teeth in a patient with severe chronic periodontitis. The panelists were questioned concerning the relative importance of each outcome measure, a minimally acceptable level considered necessary for success for each outcome measure, and the length of time required for these outcome measures to remain stable. RESULTS: The 35 panelists considered the control of pain, esthetics, and patient satisfaction to be "extremely important" outcome measures for successful periodontal treatment of single or multiple teeth. Attachment levels, probing depths, plaque levels, degree of inflammation, and mobility (for multiple teeth) were considered to be "very important" outcomes. The minimally acceptable reduction in probing depths following 1 year of treatment was 2 mm; whereas 2 mm of attachment gain was considered necessary for successful treatment. The panel also found a Miller degree I mobility as an acceptable outcome for clinical success. Finally, the panel agreed that the 1-year results of treatment should remain stable for a minimum of 5 years. CONCLUSIONS: The Delphi technique proved a practical instrument to transform expert opinion into a group consensus for relevant periodontal outcome measures. Absence of pain, esthetics, and patient satisfaction were outcome measures considered "extremely important" for successful therapy. Although panelists considered attachment loss, probing depths, and mobility somewhat less important outcomes, they wanted an attachment gain of 2 mm and would accept a degree I mobility as long as outcomes remained stable for 5 years. These data suggest that minimal standards for successful therapy of anterior teeth can be established among periodontal practitioners.

Intrapocket anesthesia for scaling and root planing in pain-sensitive patients.

BACKGROUND: In 2 previous multicenter studies evaluating the efficacy of a novel anesthetic gel (lidocaine 25 mg/g plus prilocaine 25 mg/g), there was a rather small, although statistically significant, overall difference between the active and placebo gels. There were, however, large center variations. At centers where the placebo-treated patients reported high pain scores, the difference between treatments was large, suggesting that the anesthetic gel is most effective in patients who experience the procedure as painful. The present multicenter, double-blind, randomized study evaluated the anesthetic effect of this gel in pain-sensitive patients by using a visual analog scale (VAS) and a verbal rating scale (VRS). METHODS: One hundred thirteen (113) patients with moderate to severe periodontitis were screened for pain sensitivity upon probing. Eighty-five reported VAS > or = 30 mm on probing and were included in the treatment phase (43 anesthetic and 42 placebo gel). The periodontal pockets of one quadrant in each patient were treated with gel for 30 to 45 seconds, followed by scaling and/or root planing. RESULTS: The results were similar between centers. The median overall VAS pain score was 11 mm in the anesthetic group and 27 mm in the placebo group. The Hodges-Lehmann point estimate of the treatment difference was 10 mm (P = 0.004). No pain or only mild pain was reported by 70% in the anesthetic group and by 48% in the placebo group (P = 0.003). Two patients in the anesthetic group and 7 patients in the placebo group required rescue anesthesia. CONCLUSIONS: This study confirms the favorable anesthetic efficacy of active gel over placebo in selected pain-sensitive patients. It suggests that the gel may be a valuable alternative to conventional injection anesthesia.

Subantimicrobial dose doxycycline enhances the efficacy of scaling and root planing in chronic periodontitis: a multicenter trial.

BACKGROUND: Previous studies have shown that subantimicrobial dose doxycycline (SDD) is of clinical benefit in the treatment of chronic periodontitis (CP). The aim of this study was to further assess the role of SDD as an adjunct to scaling and root planing (SRP) in the treatment of CP. METHODS: A double-blind, randomized, placebo-controlled, multicenter clinical study was conducted to test the efficacy of SDD (20 mg doxycycline B.I.D.) in combination with SRP in subjects with moderate to severe CP. Two-hundred ten subjects were treated with a standardized episode of SRP and randomized to receive either adjunctive SDD or placebo for 9 months. Efficacy parameters included per-subject mean changes in clinical attachment level (CAL) and probing depth (PD) from baseline, and the total number of sites with attachment gains and probing depth reductions > or = 2 mm and > or = 3 mm from baseline. RESULTS: In periodontal sites with PD 4 to 6 mm and > or = 7 mm (N = 209, intent-to-treat population), mean improvements in CAL and PD were greater following SRP with adjunctive SDD than SRP with placebo, achieving statistical significance in all baseline disease categories at month 9 (P < 0.05). At month 9, 42.3% of sites in the SDD group demonstrated CAL gain > or = 2 mm compared to 32.0% of sites in the placebo group (P < 0.01). CAL gain > or = 3 mm was seen in 15.4% of sites in the SDD group compared to 10.6% of sites in the placebo group (P < 0.05). When considering the same thresholds of change in PD, 42.9% of sites in the SDD group compared to 31.1% of sites in the placebo group demonstrated PD reduction > or = 2 mm (P < 0.01), and 15.4% of sites in the SDD group compared to 9.1% of sites in the placebo group demonstrated PD reduction > or = 3 mm (P < 0.01). CONCLUSION: Adjunctive subantimicrobial dose doxycycline enhances scaling and root planing. It results in statistically significant attachment gains and probing depth reductions over and above those achieved by scaling and root planing with placebo.

Three-dimensional fit of lithium disilicate partial crowns in vitro.

OBJECTIVES: A novel three-dimensional scanning technique was used to investigate the effects a one-step and a two-step impression methods can have on the three-dimensional fit of ceramic partial crowns. METHODS: An acrylic model of a mandibular first molar was prepared to receive a partial coverage all-ceramic crown (mesio-occlusal-distal inlay preparation with reduction of all cusps and rounded shoulder finish line of buccal wall). Type IV plaster replicates were cast based on one-step single viscosity (OS/SV), one-step dual viscosity (OS/DV), and two-step dual viscosity (TS/DV) impressions. Five partial crowns were fabricated per impression method using hot-pressed lithium disilicate ceramics. Then, preparation and restorations were digitized using a non-contact, white-light scanner featuring self-calibrating optics (overall measurement uncertainty of <5µm). Data were entered into quality inspection software which superimposed the records (best-fit-algorithm), calculated fit-discrepancies for every pixel, and colour-coded the results to aid visualization. Furthermore, mean quadratic deviations (RMS) were computed and analyzed statistically with a 1-way ANOVA. Scheffé's procedure was applied for multiple comparisons (α=0.05). RESULTS: Mean RMS-values for marginal (internal) surfaces were: OS/SV 70 (20)µm, OS/DV 78 (34)µm, and TS/DV 107 (52)µm. Differences among impression techniques were statistically significant at p=0.006 (0.001). Qualitatively, occlusal ridges and preparation finish lines were over contoured, whereas inner occlusal boxes and the proximal-occlusal isthmus were under contoured. CONCLUSIONS: OS/SV and OS/DV impressions resulted in statistically significantly smaller marginal and internal discrepancies than the two-step technique. CLINICAL SIGNIFICANCE: Marginal and internal fit of hot-pressed lithium disilicate partial crowns depended on the employed impression technique. One-step impressions are preferred over two-step techniques in many day-to-day clinical situations, especially for the fabrication of partial coverage crown restorations.

Effect of CNC-milling on the marginal and internal fit of dental ceramics: a pilot study.

OBJECTIVES: Machined restorations have been investigated for their preciseness before, while detailed information on the milling-step itself are lacking. Therefore, the aim of this laboratory study was to quantify the effect of a novel milling-procedure on the marginal and internal fit of ceramic restorations. METHODS: An acrylic model of a lower left first molar was prepared to receive a ceramic partial crown and was duplicated by one step dual viscosity impressions. Gypsum casts were formed and laser-scanned to realize virtual datasets, before restorations were designed, exported (PRE) and machined from lithium disilicate blanks. Crowns were digitized by a structure-light-scanner to obtain post-milling-data (POST). PRE and POST were virtually superimposed on the reference tooth and subjected to computer-aided-inspection. Visual fit-discrepancies were displayed with colors, while root mean square deviations (RMSD) and degrees of similarity (DS) were computed and analysed by t-tests for paired samples (n=5, α=0.05). RESULTS: The milling procedure resulted in a small increase of the marginal and internal fit discrepancies (RMSD mean: 3µm and 6µm, respectively). RMSD differences were not statistically significant (p=0.495 and p=0.160 for marginal and internal fit, respectively). These results were supported by the DS data. SIGNIFICANCE: The products of digital dental workflows are prone to imprecisions. However, the present findings suggest that differences between computer-aided designed and actually milled restorations are small, especially when compared to typical fit discrepancies observed clinically. Imprecisions introduced by digital design or production processes are small.

Biomimetic mineralization: long-term observations in patients with dentin sensitivity.

OBJECTIVE: Cervical tooth erosion is increasingly observed among adults and frequently associated with dentin sensitivity (DS). This study evaluated the effectiveness on DS of a biomimetic mineralization system (BIMIN) in comparison to the current standard treatment (Gluma(®) Desensitizer, Gluma). METHODS: In this single-blind, 2-arm study, 40 patients with confirmed cervical DS were randomized to either the test group or the positive control group. A Visual-Analog-Scale (VAS) was used to assess DS following stimulation of the exposed dentin with a 2-s air blast. Assessments were made at baseline (pre-treatment), 2 days, 4, 8 and 12 weeks, and 12 months after treatment. Two-stage replicas were obtained from the treated teeth and gold sputtered at baseline, and 2 days, 3 and 12 months after treatment. Surface topography of the treated cervical lesions and occlusion of dentinal tubules were investigated using scanning electron microscopy (SEM). RESULTS: Both treatments led to a statistically significant reduction (P<0.0001) in DS that persisted over the entire 12-month observation period. Differences in DS between the treatments were not statistically significant. SEM photomicrographs demonstrated that a mineral layer concealed the dentinal tubules in the test group. In contrast, numerous dentinal tubules remained visible in cervical defects that were treated with Gluma. SIGNIFICANCE: A biomimetic mineralization kit was successfully used to treat patients exhibiting DS. The effect was similar to using Gluma, and was likely the result of the deposition of an enamel-like layer on the exposed cervical dentin.

Adjunctive subantimicrobial dose doxycycline in smokers and non-smokers with chronic periodontitis.

OBJECTIVES: Previous studies have demonstrated the clinical benefits of sub-antimicrobial dose doxycycline (SDD) in the treatment of chronic periodontitis (CP). The aim of this study was to retrospectively evaluate the role of SDD as an adjunct to scaling and root planing (SRP) in the treatment of smokers and non-smokers with CP. MATERIAL AND METHODS: A meta-analysis of two previously reported clinical studies was undertaken. Both were 9-month, double-blind, randomized, placebo-controlled, multi-centre clinical trials that investigated the efficacy of SDD (20 mg doxycycline twice daily) in combination with SRP in subjects with moderate-severe CP. 36.9% of the combined study population were smokers. Three hundred and ninety-two subjects were included in the meta-analysis, which evaluated per-subject mean changes in clinical attachment level (CAL) and probing depth (PD) from baseline and the total number of sites with attachment gains and PD reductions > or =2 and > or =3 mm from baseline in four subgroups: smokers/SDD; smokers/placebo; non-smokers/SDD; non-smokers/placebo. RESULTS: A hierarchical treatment response was observed, with non-smokers who received SDD demonstrating the greatest CAL gains and PD reductions. Smokers who received placebo demonstrated the smallest clinical improvements following treatment. Smokers who received SDD demonstrated an intermediate treatment response that was broadly equivalent to that seen in non-smokers who received placebo. In sites with baseline PD 4-6 mm, month 9 CAL gains were 19-45% better in non-smokers who received SDD compared with all other subgroups (p<0.05), and were 21% greater in smokers who received SDD compared with smokers who received placebo (p<0.05). Furthermore, month 9 PD reductions were 21-53% greater in non-smokers who received SDD compared with all other subgroups (p<0.01), and were 26% greater in smokers who received SDD compared with smokers who received placebo (p<0.05). CONCLUSION: Adjunctive SDD enhances therapeutic outcomes compared with SRP alone, resulting in clinical benefit in both smokers and non-smokers with CP.

Long-term treatment with sub-antimicrobial dose doxycycline has no antibacterial effect on intestinal flora.

AIM: The purpose of this study was to determine if a 9-month regimen of sub-antimicrobial doxycycline (20 mg, bid) had an effect on either the intestinal or the vaginal microflora. MATERIAL AND METHODS: A total of 69 periodontally diseased subjects were randomized to receive drug or placebo control for a 9-month period. Stool specimens and vaginal swabs were collected at baseline and after 3 and 9 months of therapy. Samples were examined for total anaerobic counts, opportunistic pathogens, and doxycycline-resistant (>or=4 microg/ml) bacteria. All isolates that survived sub-culture were identified and their susceptibilities determined to six antibiotics. Analyses were performed to determine if treatment differences were present. RESULTS: The only statistically significant differences (p<0.05) between the two treatment groups occurred in the doxycycline-resistant counts at the baseline sample period for the faecal samples. This imbalance was before treatment initiation and the administration of the study drug. No between-treatment differences were detected at either the 3- or 9-month sample period either in the predominant bacterial taxa present or in their antibiotic susceptibilities. CONCLUSIONS: There was no evidence that sub-antimicrobial doxycycline treatment exerted an effect on the composition or doxycycline resistance level of either the faecal or the vaginal microflora.

Adjunctive subantimicrobial dose doxycycline in the management of institutionalised geriatric patients with chronic periodontitis.

OBJECTIVE: To assess the efficacy of subantimicrobial dose doxycycline (SDD; 20 mg doxycycline twice daily) as an adjunct to scaling and root planing (SRP) in the treatment of moderate-severe chronic periodontitis (CP) in institutionalised elderly patients aged 65 years or older. BACKGROUND: Previous studies have shown that SDD is of clinical benefit in the treatment of CP. However, the benefits of SDD in geriatric populations (65+ years) have not been determined. MATERIAL AND METHODS: A 9-month, double-blind, randomised, placebo-controlled pilot study was conducted. 24 institutionalised geriatric patients (65 years or older) with evidence of CP manifested by baseline clinical attachment levels (CAL) 5-9 mm, probing depths (PD) 4-9 mm and bleeding on probing (BOP) were recruited. At baseline, patients were treated by a standardised episode of SRP, and randomised to receive either adjunctive SDD or placebo. Full mouth PD and CAL were measured using the manual UNC-15 periodontal probe at 3, 6, and 9 months post-baseline to assess the response to treatment. Periodontal sites were stratified by baseline PD value: sites with PD 4-5 mm were considered moderately diseased and sites with PD > or = 6 mm severely diseased. RESULTS: The SRP + placebo resulted in PD reductions similar to those reported previously in the literature. At all time-points and in both moderate and deep sites, SRP + SDD resulted in significantly greater PD reductions relative to baseline than SRP + placebo. At month 9, in moderate sites, mean PD reductions of 1.57 +/- 0.11 mm were reported in the adjunctive SDD group, compared with 0.63 +/- 0.11 mm in the adjunctive placebo group (p < 0.001). In deep sites at month 9, mean PD reductions of 3.22 +/- 0.29 mm were reported in the adjunctive SDD group, compared with 0.98 +/- 0.31 mm in the adjunctive placebo group (p < 0.05). Similar improvements were observed for CAL in the SDD group compared with the placebo group. Significantly lower BOP scores were also recorded at month 9 in the SDD group (7.5%) compared with the placebo group (71.2%) (p < 0.01). CONCLUSION: SDD used as an adjunct to SRP provides significant benefit for elderly patients with CP compared with SRP alone.