Digital versus conventional prosthetic workflow for dental students providing implant-supported single crowns: A randomized crossover study.

STATEMENT OF PROBLEM: Digital scanning has become popular and has been reported to be more comfortable for patients and equally or more accurate than conventional impression techniques. However, clinical evidence to support the advantages of digital scanning is sparse. PURPOSE: The purpose of this randomized crossover study was to examine and compare the patient and provider perceptions of digital scanning and conventional impression making for implant-supported single crowns (ISSCs) provided by dental students under supervision. Furthermore, the quality and patient-reported outcome of the definitive restorations were compared. MATERIAL AND METHODS: Forty participants in need of a single tooth replacement were enrolled. Three months after initial implant placement, recordings were made for implant-supported crowns. The participants were randomized into a conventional or a digital group but underwent both procedures. Only the designated impression or scan was sent to the dental laboratory technician to be processed. All participants and students were asked questions concerning which technique they preferred. Furthermore, the participants filled out an oral health impact profile (OHIP-14) questionnaire before and after treatment. The restorations' esthetic and technical quality was evaluated using the Copenhagen Index Score (CIS). RESULTS: The participants preferred the digital technique (80%) over the conventional technique (2%), while 18% of the participants had no preference. The participants were bothered significantly more (P<.001), experienced significantly more shortness of breath (P<.001), and were significantly more anxious during the conventional impression than during the digital scan (P<.001). Most students also preferred the digital technique (65%) over the conventional technique (22%), and 13% had no preference. The students found that the conventional impression procedure was less time-consuming but more uncertain in comparison with the digital technique. The digital technique was perceived as significantly more impractical than the conventional technique (P<.05). The results from CIS showed no significant difference in the quality of the restorations. Following treatment, the OHIP-14 scores showed a significant drop, suggesting an increase in oral health-related quality of life (P<.001). CONCLUSIONS: The perceptions of the participants and students of the digital intraoral scanning were significantly better than those of the conventional technique. No significant differences in the quality of the restorations or OHIP scores were observed using the two recording techniques.

SURVIVAL RATE OF IMPLANT-SUPPORTED, SINGLE-TOOTH RESTORATIONS BASED ON ZIRCONIA OR METAL ABUTMENT IN PATIENTS WITH TOOTH AGENESIS: A 5-YEARS PROSPECTIVE CLINICAL STUDY.

OBJECTIVES: The primary aim was to investigate survival rate of zirconia versus metal abutments, and the secondary aim was clinical outcomes of all-ceramic versus metal-ceramic crowns on single-tooth implants. METHODS: Patients with tooth-agenesis participated to previously published prospective clinical study with 3-year follow-up were recalled after 5 years. Biological variables included survival and success rate of implants, marginal bone level, modified Plaque and Sulcus Bleeding Index and biological complications. Technical variables included restoration survival rate, marginal adaptation and technical complications. The aesthetic outcome of crowns and peri-implant mucosa in addition to patient-reported outcome were recorded. Descriptive analysis, linear mixed model for quantitative data, or generalized linear mixed model for ordinal categorical data were applied; significance was set to 0.05. RESULTS: Fifty-three patients (mean age: 32.4 years), with 89 implants participated to the 5-years examination. The implants supported 50 zirconia abutments with 50 all-ceramic (AC) crown and 39 metal abutments with 29 metal-ceramic (MC) and 10 AC crowns. The Implant and restoration survival rate was 100% and 96%, respectively. No clinically relevant biological difference between implants supporting metal or zirconia abutments was registered. The technical complications were veneering fracture of AC-crowns (n = 3), crown loosening of MC-crowns (n = 4) and one abutment screw loosening (MC-crown on metal abutment). MC-crowns had significantly better marginal adaptation than AC-crowns (p = .01). AC-crowns had significantly better color and morphology than MC-crowns (p = .01). CONCLUSIONS: Zirconia-based single-tooth restorations are reliable alternative materials to metal-based restorations with favorable biological and aesthetic outcome, and few technical complications.

Patient-reported outcomes for bone regenerative procedures.

Evidence-based dentistry used for decision-making and assessment of treatment includes three components: evidence from the literature, clinical expertise, and patient expectations. Patient satisfaction embraces affability, availability, and ability and can be examined using questionnaires or structured questions to the patient to evaluate patient perception of the treatment. The questions can be quantified using dichotomous, point, or visual analog scales. This would be a straightforward patient-reported outcome measure (PROM). Validated and specific oral health-related quality of life (OHRQoL) questionnaires such as the oral health impact profile (OHIP), oral impact on daily performance (OIDP), or the dental impact on daily living (DIDL) can be used as PROMs, and these measures are appropriate for population studies, where you can measure changes over time and differences between treatment groups. PROMs have shown to enhance patient engagement when integrated into clinical care. PROMs for bone regenerative procedures are mainly used as secondary outcome and are concentrating on the prosthetic outcome more than the pain, discomfort, anxiety, and cost of the surgical procedures. Surprisingly, most patients are satisfied and willing to have the procedures performed again. Whether this is recall bias or not and how the information's from the dentist and the team influence the patients answers to PROMs questionnaires are discussed. The importance of patient perspectives in bone regeneration procedures is obvious and combined with clinical outcome measures, it increases our ability to provide better care. Studies using PROMs as a primary outcome variable are required.

Efficacy and risks of removable partial prosthesis in periodontitis patients: A systematic review.

AIM: The aim of this systematic review was to answer the following focused question: "In partially edentulous patients with periodontitis, are removable dental prostheses (RDPs) more efficacious than no prosthetic treatment, treatment to a shortened dental arch (SDA), or tooth-supported fixed dental prostheses (FDPs)?" MATERIALS AND METHODS: A systematic literature search was performed electronically for the period 1966-2020. Two authors independently assessed the studies for eligibility according to the PRISMA guidelines. Risk assessment was performed using RoB 2.0 and the Newcastle-Ottawa Scale. RESULTS: Two retrospective studies indicated that RDPs increased the risk of tooth loss compared to FDPs in patients with a history of periodontitis. Prospective studies found that RDPs could be maintained without any significant periodontal destruction on a long-term basis. Owing to the heterogeneity of the data, no meta-analysis could be performed. Several studies indicated that RDP increased plaque accumulation. RDPs had only a limited effect on masticatory efficiency and nutritional status. RDPs may improve oral-health-related quality of life (OHRQoL), but to a lesser extent compared with that of patients treated to an SDA. CONCLUSIONS: There is no strong evidence that RDPs per se will cause periodontal destruction including tooth loss. RDPs do not inevitably improve masticatory efficiency but improve OHRQoL, although less than for patients treated with FDPs including resin-bonded FDPs.

A 5-year randomized controlled trial comparing zirconia-based versus metal-based implant-supported single-tooth restorations in the premolar region.

OBJECTIVE: To compare 5-year biological, technical, aesthetic, and patient-reported outcomes of single-tooth implant-supported all-ceramic versus metal-ceramic restorations. MATERIALS AND METHODS: Thirty patients with 63 premolar agenesis participated in the 5-year follow-up. The prosthetic treatment on single-tooth implants was randomly assigned to all-ceramic crowns on zirconia abutments (AC = 31) or metal-ceramic crowns on metal abutments (MC = 32). All patients were recalled to clinical examinations at baseline, 1, 3, and 5 years after prosthetic treatments. Biological, technical, and aesthetic outcomes including complications were clinically and radiographically registered. The patient-reported outcomes were recorded using OHIP-49 questionnaire before treatment and at each follow-up examination. RESULTS: At the 5-year examination, the survival rate was 100% for implants and 100% for AC and 97% for MC crowns and abutments. The marginal bone loss after 5 years was minor and not significantly different (p = .056) between AC (mean: 0.3, SD: 1.1) and MC (mean: -0.1, SD: 0.4) restorations. The success rate of the implants based on marginal bone loss was 77.4% for AC- and 93.7% for MC restorations. The marginal adaptation was significantly better for MC than for AC restorations (p = .025). The aesthetic outcomes and patient-reported outcomes between AC and MC restorations were not significantly different. CONCLUSIONS: The biological, aesthetic and patient-reported outcomes for implant-supported AC and MC restorations were successful and with no significant difference after 5-years. The marginal adaptation of the MC crowns cemented on titanium abutments showed a significantly better fit than restorations based on zirconia crowns cemented on zirconia abutments.

Patient's perception of timing concepts in implant dentistry: A systematic review.

Protocols for implant dentistry, most frequently include periods until healing of the extraction sockets and osseointegration of the implant. Deductional thinking imply that patients would prefer if treatment time in implant dentistry were reduced. AIM: What is the patient perception of immediate or early implant placement or loading in comparison with traditional, delayed placement, and/or loading assessed by patient-reported outcome measures, as evidenced in randomized controlled clinical trials or prospective controlled studies? MATERIAL AND METHODS: A systematic review was performed following the PRISMA guidelines with a literature search up to June 30. All hits were imported into Rayyan online software and analyzed by two authors for eligibility. Cochrane RoB2.0 and Newcastle-Ottawa Scale were used to evaluate risk of bias in the individual studies. RESULTS: Of the initially 1439 articles, 76 underwent full-text analysis and finally 40 articles, representing 35 cohort studies, were included. The quality evaluation demonstrated some concerns among most of the studies. CONCLUSION: a) There is no strong evidence to support that the time for implant placement or loading of implant-supported single or short-span reconstructions or overdentures influence patients´ discomfort, satisfaction with function or esthetics or overall satisfaction with the implant treatment. b) There is some evidence that studies including edentulous patients rehabilitated with implant-supported full-arch FDPs demonstrate more satisfied patients with immediate than for the early or delayed loaded implant reconstructions after short time, but the difference is not clear one year after treatment.

Fully versus conventionally guided implant placement by dental students: A randomized controlled trial.

OBJECTIVE: To compare fully guided with conventionally guided implant surgery performed by dental students in terms of deviation of actual implant position from an ideal implant position. MATERIALS AND METHODS: Twenty-five patients in need of 26 straightforward implant-supported single crowns were randomly allocated to a fully guided (FG, n = 14) or a conventionally guided (CG, n = 12) implant surgery. In the preoperative CBCTs, 3 experienced investigators placed a virtual implant in the ideal position, twice, allowing deviational analysis in the facio-lingual (coronal) and mesio-distal (sagittal) planes for 7 parameters. Facio-lingual crestal deviation, facio-lingual apical deviation, facio-lingual angular deviation, mesio-distal crestal deviation, mesio-distal apical deviation, mesio-distal angular deviation, and vertical deviation between the ideal, virtually placed position and actual implant position for the FG and CG groups were compared statistically (p < .05). RESULTS: Statistically significant differences between ideal and actual implant position were only seen for the facio-lingual apical deviation (p = .047) and for the facio-lingual angular deviation (p = .019), where the CG group deviated more from the ideal position than the FG group. The 5 other examined variables did not show any significant differences, and none of the implants in the FG group and CG group were placed in conflict with the clinical guidelines. CONCLUSIONS: The present study reported no difference in 5 out of 7 deviational parameters concerning actual implant position in relation to ideal implant position between a FG and CG implant placement protocol performed by dental students. Facio-lingual angular deviation and apical deviation were lower, when a FG protocol was followed. All implants were positioned according to clinical guidelines.

Impact of timing of dental implant placement and loading: Summary and consensus statements of group 1-The 6th EAO Consensus Conference 2021.

OBJECTIVES: This publication reports on the EAO workshop group 1 summaries, discussions and consensus statements based on four systematic reviews evaluating the impact of timing of dental implant placement and loading. MATERIALS AND METHODS: The first of the systematic reviews was on the influence of the timing of implant placement and loading in the biological outcomes of implant-supported fixed partial dentures. The second systematic review evaluated the influence of the timing of implant placement and loading on the aesthetic outcomes in single-tooth implants. The third systematic review was on the long-term outcomes of maxillary single-tooth implants in relation to timing protocols of implant placement and loading and the fourth on patient's perception of timing concepts in implant dentistry. The group evaluated these systematic reviews, provided comments and additions as required and agreed on the relevant consensus statements as well as on clinical and research recommendations. RESULTS: Different timings of implant placement/loading presented with high implant survival rates. The systematic reviews evaluated from this working group provided a number of conclusions based on the available/current literature. However, the specific topic of timing is an area that further research is required in order to provide detailed guidelines for the different protocols to be employed.

Tissue changes at implant sites in the anterior maxilla with and without connective tissue grafting: A five-year prospective study.

OBJECTIVES: To evaluate the biological and aesthetic outcome of connective tissue grafting around single-tooth implant replacements in the anterior maxilla after five years. MATERIALS AND METHODS: Nineteen patients (mean age: 22) received 33 implants in combination with bone grafts. After healing, 10 implant sites received facial connective tissue grafts harvested from the palate (test group). The remaining 23 implant sites without soft tissue grafts were used as a control group. The biological outcomes included survival rate, complications, marginal bone level, keratinized mucosa height and soft tissue level. The aesthetic outcomes included soft tissue thickness, spectrophotometric colour of mucosa, 3D facial dimensional changes and professional reported aesthetic outcomes. All data were recorded preoperatively and postoperatively after six months and one, three and five years. RESULTS: After five years, the survival and success rate of implants was 100% and 93.9% (one aesthetic and one biological complication). The soft tissue level changed significantly more towards the incisal direction in the test than in the control group from one to five years of observation (p = .024). The facial dimension increased significantly more in the test group than in the control group (3 mm marginally: p = .010). The subjective evaluation of mucosa colour was significantly better in the test versus control group (p = .035). Other biological and aesthetic parameters were not significantly different between the test and control group. CONCLUSION: Augmentation using a connective tissue graft may result in better mucosal colour match and more facial dimensional gain compared to implant sites without soft tissue grafting.

Patient-reported effect in patients receiving implant or tooth-supported fixed prosthesis.

OBJECTIVES: To compare the patient-reported effect of treatment with implant-supported fixed prosthesis (ISFP) and fixed dental prosthesis (FDP) in patients with a small number of tooth losses to replace. METHODS: From a population of 155 patients receiving either ISFP or FDP, 68 patients were matched in pairs based on gender, number of teeth replaced, zone of replacement, age and number of remaining teeth. The patient-reported effect was prospectively obtained by measuring change in the short-form oral health impact (OHIP-14) from before to one month after treatment. Effect size (ES), standardised response mean (SRM) and a minimal important difference of two units were applied to estimate the magnitude of the change. RESULTS: Both the ISFP and FDP groups decreased significantly in OHIP-14 after treatment (P < .01). The change was not significantly different between the ISFP and FDP groups. The magnitude of the change was for both treatments moderate and slightly higher in the ISFP group (ES = 0.52 and SRM = 0.58) than in the FDP group (ES = 0.48 and SRM = 0.47). Applying the minimal important difference showed that 23 participants in the ISFP group and 21 in the FDP group had good effect. CONCLUSIONS: The patient-reported effect of treatment with ISFP or FDP was similar, clinically meaningful and of moderate magnitude in patients with a small number tooth losses to replace.

Implant-supported 2-unit cantilevers compared with single crowns on adjacent implants: A comparative retrospective case series.

STATEMENT OF PROBLEM: The replacement of 2 adjacent missing teeth remains a clinical challenge. Among the different treatment options, the use of a single implant to support a 2-unit cantilever fixed dental prosthesis (FDP) has been proposed in situations of limited mesiodistal space, even though the evidence for its use is low. PURPOSE: The purpose of this retrospective comparative case series was to evaluate hard and soft peri-implant tissues in patients with 2 adjacent missing teeth in the anterior area (incisors or canines) rehabilitated with implant-supported 2-unit cantilevers or single crowns on adjacent implants. MATERIAL AND METHODS: Twenty-three from a cohort of 34 patients rehabilitated with 2-implant systems between September 2006 and November 2015 with 2-unit cantilever FDPs (test group) (n=16) or 2 adjacent dental implants supporting single crowns (control group) (n=7) were available for follow-up. At the baseline and follow-up examinations, the implant survival rate, peri-implant probing pocket depth, marginal bone level (MBL), as well as papilla scores and prosthetic outcomes from the Copenhagen Index Score were recorded and evaluated. RESULTS: One implant in the control group was lost during the observation period, leading to an overall implant survival rate of 97%. Mean peri-implant probing depths were low (≤5 mm) in both the groups. Stable marginal bone levels were detected around adjacent implants and around implants supporting cantilevers. Medium to high esthetic scores were obtained in most patients. Papilla index scores were high (score 1 and 2) in both the groups. Finally, no technical complications were recorded. CONCLUSIONS: The use of a single-implant-supported 2-unit cantilever FDP in anterior sites is a valid treatment option compared with 2 adjacent implants, especially when the available mesiodistal space is limited.

Mechanical and biological complications after implantoplasty-A systematic review.

OBJECTIVES: Implantoplasty, that is, the mechanical modification of the implant, including thread removal and surface smoothening, has been proposed during surgical peri-implantitis treatment. Currently, there is no information about any potential mechanical and/or biological complications after this approach. The aim of the current review was to systematically assess the literature to answer the focused question "Are there any mechanical and/or biological complications due to implantoplasty?". MATERIALS AND METHODS: A systematic literature search was performed in three databases until 23/09/2018 to assess potential mechanical and/or biological complications after implantoplasty. All laboratory, preclinical in vivo, and clinical studies involving implantoplasty were included, and any complication potentially related to implantoplasty was recorded and summarized. RESULTS: Out of 386 titles, 26 publications were included in the present review (six laboratory, two preclinical in vivo, and 18 clinical studies). Laboratory studies have shown that implantoplasty does not result in temperature increase, provided proper cooling is used, but leads in reduced implant strength in "standard" dimension implants; further, preclinical studies have shown titanium particle deposition in the surrounding tissues. Nevertheless, no clinical study has reported any remarkable complication due to implantoplasty; among 217-291 implants subjected to implantoplasty, no implant fracture was reported during a follow-up of 3-126 months, while only a single case of mucosal discoloration, likely due to titanium particle deposition, has been reported. CONCLUSIONS: Based on all currently available, yet limited, preclinical in vivo and clinical evidence, implantoplasty seems not associated with any remarkable mechanical or biological complications on the short- to medium-term.

Patient-reported effect of oral rehabilitation.

OBJECTIVES: To quantify the patient-reported effect of oral rehabilitation and investigate aspects associated with this. METHODS: The patient-reported effect in participants treated with fixed dental prosthesis (FDP; n = 72) or removable dental prosthesis (RDP; n = 58) was measured using the Oral Health Impact Profile 14 (OHIP-14) and global oral ratings (GOR) of aesthetics, chewing and comfort before and after treatment and global transition judgements (GTJ) of aesthetics, chewing and comfort after treatment. Explanatory variables included gender, age, if a prosthetic replacement was present before treatment, type of prosthetic treatment performed, number of teeth replaced and zone of the teeth replaced. RESULTS: The RDP and FDP treatments both significantly improved the OHIP-14 score with a moderate to large effect and most participants had good patient-reported effect. The effect varied depending on the method used. In the bivariate analyses, the number of participants with good effect was higher in the RDP group than the FDP group when using the OHIP-14 and GOR whereas the effect was higher in the FDP group when using the GTJ. Multiple regression analyses showed that poor chewing ability before treatment was associated with good effect measured by the OHIP-14 and GOR and that poor effect in chewing ability and RDP treatment was associated with poor effect in comfort measured by GTJ. Functional problems after treatment were associated with no/poor effect. CONCLUSIONS: Oral rehabilitation with fixed or removable prostheses in general yields good patient-reported effect. Masticatory aspects highly influence the patient-reported effect and treatment with RDP is associated with poor effect in oral comfort.

Oral health-related quality of life, oral aesthetics and oral function in head and neck cancer patients after oral rehabilitation.

Head and neck cancer (HNC) is diagnosed in more than 500 000 patients every year worldwide with increasing prevalence. Oral rehabilitation is often needed after HNC treatment to regain oral function, aesthetics and oral health-related quality of life (OHRQoL). The objectives were to evaluate OHRQoL, oral aesthetics and oral function after oral rehabilitation in HNC patients and compare it to that of non-HNC patients. Eighteen patients treated for HNC who subsequently had oral rehabilitation (2014-2017), and a control group of eighteen age- and gender-matched non-HNC patients treated with removable prostheses (2014-2018) were included in a cross-sectional study. The OHRQoL was assessed by the Oral Health Impact Profile 49 questionnaire (OHIP-49), the oral aesthetics by the Prosthetic Esthetic Index (PEI) and the Orofacial Esthetic Scale (OES), and the oral function by the Nordic Orofacial Test-Screening (NOT-S). The HNC patients had worse oral function and OHRQoL than the control patients (mean NOT-S score 4.56 vs 0.56, P < 0.01 and mean OHIP-49 score 42.50 vs 20.94, P = 0.050). When including number of replaced teeth and type of prosthesis in the tests, no significant difference in OHRQoL was found between the groups. No difference was found in the overall aesthetic outcomes (mean PEI total score 32.28 vs 30.67, P = 0.367 and mean OES total score 48.78 vs 53.56, P = 0.321). Multiple regression analyses showed that being HNC patient compared to control patient impaired the oral function. Oral function is significantly impaired in HNC patients compared to non-HNC patients after oral rehabilitation.

Evaluation of marginal and internal fit of acrylic bridges using optical coherence tomography.

BACKGROUND: The potential of non-invasive optical coherence tomography (OCT) as a tool for assessment of fit of indirect reconstructions is not fully explored. OBJECTIVES: The objectives were to investigate the feasibility and validity of OCT, and to measure the internal and marginal fit of acrylic bridges fabricated using direct and indirect digitalisation. METHODS: The accuracy of the employed swept source OCT (wavelength: 1310 nm) was assessed by comparing with an object with known dimensions. Validity was assessed by measuring an OCT measurements on replica, mimicking the cement film thickness, with stereomicroscopic measurements. The reconstructions were placed on the abutments without cementation. The internal and marginal fit of acrylic bridges from direct and indirect digitalisation techniques were then assessed by obtaining 5 OCT B-scans per abutment tooth at pre-defined positions located 250 µm apart. The marginal and internal cement gaps were measured using image-processing software (ImageJ). Mean and standard deviation were calculated for both groups and t test assuming unequal variances was carried out. The level of significance was defined at 0.05. RESULTS: A strong linear correlation (r = 0.865) between OCT and stereomicroscopy was found. T test showed significantly (P < 0.01) better internal fit of bridges made from indirect digitalisation, but no difference in marginal fit. CONCLUSION: OCT is a feasible and valid tool for investigating internal and marginal fit of acrylic dental reconstructions. Better internal fit was observed in bridges fabricated using the direct digitalisation technique. No difference in marginal fit was found between the two fabrication methods.

Reconstructive aspects: Summary and consensus statements of group 3. The 5th EAO Consensus Conference 2018.

OBJECTIVES: The tasks of this working group were to evaluate the existing evidence on the efficiency and efficacy of the digital and conventional workflows for the fabrication of fixed implant reconstructions, to assess the performance of all-ceramic fixed implant reconstructions and, finally, to evaluate the outcomes of internally and externally connected implant abutments and reconstructions. METHODS: Four reviews were available analyzing the current literature on the respective topics. One review dealt with the efficiency and efficacy of digital and conventional fabrication workflows. Two reviews analyzed the outcomes of all-ceramic fixed implant reconstructions, one focusing on single-implant reconstructions and the other evaluating multiple-unit implant fixed dental prostheses (FDPs). The fourth review evaluated the clinical outcome on external, respectively, internal implant-abutment connections. These reviews were the basis for the discussions within the group and at the plenary sessions. RESULTS: The present consensus report gives the consensus statements, the clinical recommendations, and the implications for future research as discussed and approved by the plenum of the consensus conference. The four manuscripts by Mühlemann et al., Rabel et al., Pieralli et al., and Pjetursson et al. are published as part of the journal supplement of the present EAO consensus conference.

Accuracy of stereolithography additive casts used in a digital workflow.

STATEMENT OF PROBLEM: Despite the increasing demand for a digital workflow in the fabrication of indirect restorations, information on the accuracy of the resulting definitive casts is limited. PURPOSE: The purpose of this in vitro study was to compare the accuracy of definitive casts produced with digital scans and conventional impressions. MATERIAL AND METHODS: Chamfer preparations were made on the maxillary right canine and second molar of a typodont. Subsequently, 9 conventional impressions were made to produce 9 gypsum casts, and 9 digital scans were made to produce stereolithography additive (SLA) casts from 2 manufacturers: 9 Dreve SLA casts and 9 Scanbiz SLA casts. All casts were then scanned 9 times with an extraoral scanner to produce the reference data set. Trueness was evaluated by superimposing the data sets obtained by scanning the casts with the reference data set. Precision was evaluated by analyzing the deviations among repeated scans. The root mean square (RMS) and percentage of points aligned within the nominal values (±50 µm) of the 3-dimensional analysis were calculated by the software. RESULTS: Gypsum had the best alignment (within 50 µm) with the reference data set (median 95.3%, IQR 16.7) and the least RMS (median 25.8 µm, IQR 14.6), followed by Dreve and Scanbiz. Differences in RMS were observed between gypsum and the SLA casts (P<.001). Within 50 µm, gypsum was superior to Scanbiz (P<.001). Gypsum casts exhibited the highest precision, showing the best alignment (within 50 µm) and the least RMS, followed by Scanbiz and Dreve. CONCLUSIONS: This study found that gypsum casts had higher accuracy than SLA casts. Within 50 µm, gypsum casts were better than Scanbiz SLA casts, while gypsum casts and Dreve SLA casts had similar trueness. Significant differences were found among the investigated SLA casts used in the digital workflow.

Can hyaluronan injections augment deficient papillae at implant-supported crowns in the anterior maxilla? A randomized controlled clinical trial with 6 months follow-up.

OBJECTIVES: The present randomized controlled trial aimed to assess the effect of hyaluronan (HY) injections to augment deficient interproximal papillae at implant-supported crowns in the anterior maxilla. METHODS: Twenty-two patients with a deficient papilla in the anterior maxilla next to an implant-supported crown were randomly assigned to receive twice either HY (test) or saline solution (control) injection. The following parameters were recorded prior to injection (baseline) and 3 and 6 months after injection: distance between the papilla tip and contact point (PT-CP), modified papilla index score (MPIS), and standard clinical periodontal parameters. Pain level after injection was recorded on a visual analogue scale (VAS). The deficient area was evaluated on clinical photographs, and the esthetic appearance was recorded on a VAS. Differences in mucosal volume were assessed after 3 months by intraoral scans. The bone level was assessed on periapical radiographs. RESULTS: No differences were observed between groups, neither at baseline nor at 3 and 6 months post-treatment. Mean PT-CP ranged between 1.8 mm and 2.3 mm without significant differences between groups or over time within groups; MPIS was 2 for all patients at all time points. Similarly, insignificant differences between groups or time points were observed for deficient area, gingival volume changes, bone level, and esthetic appearance. There were no differences in pain level between groups during injection, but discomfort after injection lasted longer in the test group. CONCLUSIONS: Injection of HY adjacent to maxillary anterior implant-supported crowns did not result in any clinical conspicuous volume augmentation of deficient papillae.

Adverse reaction after hyaluronan injection for minimally invasive papilla volume augmentation. A report on two cases.

OBJECTIVES: To report two cases of adverse reaction after mucosal hyaluronan (HY) injection around implant-supported crowns, with the aim to augment the missing interdental papilla. MATERIAL AND METHODS: Two patients with single, non-neighbouring, implants in the anterior maxilla, who were treated within the frames of a randomized controlled clinical trial testing the effectiveness of HY gel injection to reconstruct missing papilla volume at single implants, presented an adverse reaction. Injection of HY was performed bilaterally using a 3-step technique: (i) creation of a reservoir in the mucosa directly above the mucogingival junction, (ii) injection into the attached gingiva/mucosa below the missing papilla, and (iii) injection 2-3 mm apically to the papilla tip. The whole-injection session was repeated once after approximately 4 weeks. RESULTS: Both patients presented with swelling and extreme tenderness with a burning sensation on the lip next to the injection area, after the second injection session. In one of the cases, a net-like skin discoloration (livedo reticularis) was also noted. The symptoms lasted for up to 7 days, and in both cases, symptoms resolved without any signs of skin or mucosal necrosis or any permanent damage. CONCLUSION: Most likely, water attraction over time by the highly hygroscopic HY, exerted progressively an external vascular compression and at least partial occlusion of neighbouring blood vessels. An infection or an allergic reaction seems unlikely, since all symptoms gradually disappeared within a week irrespective use of antimicrobials, while an allergic reaction most likely would not have been restricted to one side.

Pectin nanocoating of titanium implant surfaces - an experimental study in rabbits.

INTRODUCTION: A major determinant of successful osseointegration of endosseous implants is the surface of the implant, which influences the cellular response of the surrounding tissues. A new strategy to improve osseointegration and bone healing is biochemical stimulation by surface nanocoatings that may increase adhesion of bone proteins, and bone cells at the implant surface. Nanocoating with pectins, plant cell wall-derived polysaccharides, is frequently done using rhamnogalacturonan-I (RG-I). AIM: The aim of the study was to evaluate the effect of nanocoating titanium implants with plant cell wall-derived rhamnogalacturonan-I, on bone healing and osseointegration. MATERIAL AND METHODS: Machined titanium implants were coated with three modifications of rhamnogalacturonan-I (RG-I). Chemical and physical surface properties were examined before insertion of nanocoated implants (n = 96) into the left and right tibia of rabbits. Machined titanium implants without RG-I nanocoating were used as controls (n = 32). Total number of 128 implants was placed in tibias of 16 rabbits. Fluorochrome bone labels, calcein green and alizarin red S were given intravenously after 9 and 12 days, respectively. The bone response to the nanocoated implants was analyzed qualitatively and quantitatively after 2, 4, 6, and 8 weeks of healing using light microscopy and histomorphometric methods. RESULTS: The RG-I coating influenced the surface chemical composition; wettability and roughness, making the surface more hydrophilic without any major effect on surface micro roughness compared to control implant surfaces. The different modifications of pectin RG-I did not significantly enhance bone healing and osseointegration analyzed after 2, 4, 6, and 8 weeks of healing compared to control implants. Although the qualitative analyses of the fluorochromes indicated a higher activity of bone formation in the mineralization front at the early stage, after 9 and 12 days at the RG-I nanocoated implants compared to the control implants although no significant quantitative difference was demonstrated. CONCLUSION: The present study showed that nanocoating of titanium implants with pectin RG-Is did not significantly enhance bone healing and osseointegration when placed in rabbit tibia bone.