Crown Insertion Research Articles

One-Piece Versus Two-Piece Abutments for Single Crowns in the Esthetic Zone: A Clinical Trial.

To evaluate whether a two-piece abutment is equivalent to a one-piece in peri-implant esthetics, patients' satisfaction, and oral health-related quality of life (OHRQOL) for implant-supported anterior single crown placement. Thirty implants were allocated sequentially: 15 in the one-piece abutment group (OP) and 15 in the two-piece abutment group (TP). Peri-implant esthetics were evaluated by the pink esthetic score (PES) at temporary crown insertion (T1), after tissue conditioning (T2), and at 30 days after the final crown insertion (T3). OHRQOL was measured using the OHIP-14 and satisfaction was evaluated using the visual analog scale (VAS) at baseline, T1, and T3. Treatment was considered equivalent if the 95% coefficient interval (CI) for mean difference in PES was between -1.5 and +1.5 points. Statistical analysis was performed using Mann-Whitney, SPANOVA, and Student's t-test, with Sidak's posttest, adopting p < 0.05. No differences were found between the groups for any variable and during follow-up. A significant increase in OHRQOL and satisfaction was observed at T3, when compared to baseline (p < 0.05) for both groups. Significant improvements in peri-implant esthetics were also observed throughout the treatment, particularly after tissue conditioning (p < 0.05). Primary and secondary outcomes were evaluated for equivalence, and both abutment types were considered equivalent following the insertion of the temporary crowns. Two-piece abutment was equivalent to one-piece abutment for peri-implant esthetics, quality of life, or the satisfaction of patients rehabilitated with metal-free single crowns. Tissue conditioning and final crown insertion appear to play a role in improving these outcomes.

Survival analysis of teeth following clinical crown lengthening and crown insertion procedures up to 14 years: A retrospective cohort study.

The purpose of this study was to conduct survival analysis of teeth following clinical crown lengthening procedures (CLPs) and crown insertions via a retrospective cohort study. Patient- and tooth-related data were collected from 268 participants who received CLPs from 2009 to 2015. The Kaplan-Meier curve and the log-rank tests were used to estimate the probability of survival and compare the survival probabilities among different variables. A Cox multivariate proportional hazard regression model was used to investigate the collective effects of root canal treatment (RCT) and the types of opposing dentition. The rate of tooth loss was 21.6% during the observation period from 1 to 14 years, with 58 teeth extracted. The most attributable reason for tooth extraction was coronal tooth fracture, followed by endodontic failure such as root fracture. The survival probability was 0.87 at 5 years and 0.7 at 10 years. No significant differences in the survival probabilities were found among different providers and locations, the presence of a post, and the types of crowns. The hazard ratio for tooth loss was 6.3, 95% confidence interval (CI) [2.6 to 20.9] in the teeth with RCT (p<0.001) and 2.4, 95% CI [1.1 to 4.8] in the teeth occluding implant-retained prostheses (p=0.016). Tooth loss following CLPs and crown insertions appeared least among the teeth without RCT when occluding natural teeth, while tooth loss was most among the teeth with RCT when occluding implants.

Immediate loading on two adjacent single dental implants with definitive nonsplinted restorations: A proof of concept in the posterior zone.

To evaluate clinical, clinician- and patient-reported outcomes (PROs) of two adjacent single posterior implants immediately loaded with definitive single crowns up to 1 year. Ten patients in need of two adjacent posterior single implants were included. All implants were placed applying a fully digital workflow. Definitive screw-retained single zirconia crowns were delivered within 72 h after implant placement. Clinical parameters, patient- and clinician-reported outcomes were assessed up to 1 year of follow-up. Clinical outcomes remained stable, with no implant failures or technical and biological complications throughout the observation period. Patient satisfaction was very high at baseline (crown delivery) and remained consistently high at 6 and 12 months of follow-up. Crown insertion 3 days after implant placement was rated as an easy procedure by clinicians. Two adjacent single implants with immediate definitive restorations(<72 h) in the posterior region appear to be a viable and easy treatment option to shorten the overall treatment time and potentially enhancing patient satisfaction. However, randomized controlled trials are needed to confirm the advantages of this treatment protocol over a delayed loading approach. In selected cases, immediate implant loading with definitive restorations in the posterior region appears a valuable and straightforward option to shorten the overall treatment time.

Clinical and Radiographic Outcomes of Single Implant-Supported Zirconia Crowns Following a Digital and Conventional Workflow: Four-Year Follow-Up of a Randomized Controlled Clinical Trial.

This study aimed to compare the clinical and radiographic outcomes of single posterior screw-retained monolithic implant crowns following a digital and conventional workflow and to report on the survival/complication rate after a mean 4-year follow-up. Thirty patients with a single posterior tooth missing were rehabilitated with a bone-level implant. After a healing period of ≥3 months, they were subjected to both a digital and conventional workflow to fabricate two screw-retained monolithic implant crowns. The quantitative clinical adjustments to both crowns (intrasubject comparison) and a questionnaire were recorded at try-in. Thereafter, a crown of the digital and conventional workflows was randomly inserted. At the last follow-up, the marginal bone level (MBL), peri-implant health-related parameters (bleeding on probing (BoP), plaque, pocket probing depth (PPD)), and functional implant prosthodontic score (FIPS) were assessed. Furthermore, the implant survival and success rates and technical complications were evaluated. A total of 27 patients were followed for a mean period of 4.23 ± 1.10 years. There was no significant difference between the digital and conventional workflows regarding clinical adjustments and questionnaire outcomes. More than twice as many participants recommended digital (n = 16) compared to conventional impressions (n = 7) to friends. The implant survival and success rate were 100% and 96.3%, respectively. Furthermore, two de-cementations and one fracture of the ti-base abutment occurred. There were no significant differences in BoP, plaque, and PPD metrics between the two groups. The changes in the MBL between implant crown insertion (baseline) and the last follow-up were 0.07 ± 0.19 mm and 0.34 ± 0.62 mm in the digital and conventional groups, respectively (p = 0.195). The mean overall FIPS score was 8.11 ± 1.37 (range: 5-10). The clinical and radiographic outcomes of single screw-retained monolithic implant crowns were similar between both workflows after a mean of 4 years of service. The patients did not clearly prefer an impression technique for their restoration, although they would recommend the digital impression more often to friends. Thus, decision regarding clinical workflows may be based on the patient's and/or clinician's preference.

Early implant placement in sites with ridge preservation or spontaneous healing: histologic, profilometric, and CBCT analyses of an exploratory RCT.

The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion. Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis. Patients were followed up after the final crown insertion and again at 1 year post-procedure. Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by -2.11 mm for the DBBM-C/CM group, -1.62 mm for the DBBM-C group, and -1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by -0.27 mm for the DBBM-C/CM group, -2.73 mm for the DBBM-C group, and -1.48 mm for the SH group. The median contour changes between crown insertion and 1 year were -0.19 mm in the DBBM-C/CM group, -0.09 mm in the DBBM-C group, and -0.29 mm in the SH group. Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year.

A two-year prospective study to compare the peri-implant parameters of posterior implant-supported single crowns with and without mesial proximal contact loss

Background/purposeInterproximal contact loss may lead to food impaction and result in subsequently periodontal complications. The purpose of this prospective study was to investigate the peri-implant parameters of posterior implant-supported single crowns (SCs) with and without mesial proximal contact loss after 2 years of follow-up. Material and methodsTwenty-six patients with a total of 40 posterior implant-supported SCs with mesial adjacent natural teeth were observed for 24 months after crown insertion. The mesial proximal contacts were assessed by dental floss, then were classified as tight, weak, and open contacts. The following peri-implant parameters were evaluated, including modified plaque index (MPI), modified gingival index (MGI), and probing depth (PD) were conducted at six sites per tooth (mesiofacail, midfacial, distofacial, mesiolingual, mid-lingual and distolingual) in the 6-, 12-, 18- and 24-month following visits. Furthermore, radiographs were taken regularly in 12- and 24-month recall sections for measuring the marginal bone loss (MBL). ResultsAt 12-month observation, the incidence rates of weak and open contacts were 22.5 % and 12.5 %; whereas after 24 months of clinical service, the rates came up with 12.9 % and 25.6 %, respectively. No significant differences were found between the tight, weak, and open contact groups in the parameters of MPI, MGI, or PD (P > 0.05) at 12- and 24-month follow-up. None of the mean differences of the peri-implant parameters: MPI, MGI, PD and MBL had significant differences between the tight, weak, and open contact groups after 1 and 2 years of clinical service (P > 0.05). ConclusionThe presence of open, weak, and tight mesial proximal contacts had no significant effects on the peri-implant tissue conditions.

Comparison of functional and esthetic outcomes in digital versus analog rehabilitation of one-piece screw-retained implant crowns placed at second stage surgery.

Analog and digital impressions are established procedures for restoration of single-tooth implants. In this study, single-tooth implants were restored with definitive restorations during second-stage surgery. Analog and digital workflows were compared. Eighty single-tooth implants were examined in total. In 40 implants, an index was taken immediately after implant placement using composite resin to fabricate the final crowns (analog workflow). For the other 40 single-tooth implants, intraoral intraoperative scans were performed (digital workflow) during primary surgery. The custom-fabricated screw-retained crowns were placed during second-stage surgery. Photographs and examinations for the scores were taken at the time of the follow-up visit, 1-4 years after placement of the crowns. The number of treatment appointments required was recorded and the modified pink esthetic score (PES) was determined. Additionally, the functional implant prosthetic score (FIPS) was measured. The mean PES was 12.15/14 for the digital workflow and 11.95/14 for the analog workflow. The most common deficit was incomplete papillae for both workflows. Three treatment appointments were required for both workflows: (1) Scan and/or impressions making and patient consent, (2) implant placement, and (3) second-stage surgery with crown insertion. The FIPS was 9.1/10 for the digital workflow group and 9.2 /10 for the analog workflow group. Common deficits presented as missing papillae as well as open approximal contacts. The FIPS was not significantly different between workflows (p = 0.679). The PES also did not show a statistically significant difference for both workflows (p = 0.654), however the analog workflow showed better values for the papillae (p < 0.05). A significant difference was also found in the other PES values, with the digital workflow showing better results here (p < 0.05). A chronological analysis of the results of the digital technique showed that the cases treated last had significantly better values than the cases treated first. According to the results of this study, both workflows allowed placement of the definitive crowns on single-tooth implants during second-stage surgery. Both workflows were found to be equivalent in terms of esthetic results in this study, although the digital workflow demonstrated a learning curve. This article is protected by copyright. All rights reserved.

Evaluation of Patient’s Aesthetic Satisfaction after the Cementation of the Porcelain Fused to Metal Crown

Aim: To assess the aesthetic satisfaction with the metal-ceramic dental prosthesis in relation to patient education, age and gender. Methods: This prospective longitudinal study was undertaken by selecting 360 adult patients from both genders indicated for single maxillary porcelain fused to metal crowns. These patients were categorized into three groups based on gender, age, and education. Patients were assessed for aesthetic satisfaction for tooth shape; color, angulation, visibility, and shade at the time of insertion and at a follow-up of 12 weeks. At the time of the prosthesis insertion, a self-evaluation questionnaire was provided to each patient to record their satisfaction levels with the prosthesis. Satisfaction levels among the participants were evaluated based on participants' age, gender, and education level (Chi-square). A p-value of 0.05 was considered statistically significant. Results: The study enrolled 150(41.67%) males and 210(58.33%) females with the participant age ranging from 19 to 60 years and a mean age of 30.53 (± 10.88 years). 84(23.3%) were uneducated participants, 210(58.3%) were high school graduates, and 66(18.3%) were university graduates. A decrease in the level of satisfaction was observed with increasing years of patient education at insertion. The overall aesthetic satisfaction among patients at PFM crown insertion (65%) and at 12 weeks follow-up (69.2%) was statistically comparable (p&gt;0.05). Practical implication: Aesthetic is the most important consideration for the replacement of anterior teeth. Numerous studies evaluated the aesthetic satisfaction of the patients after providing full ceramic prosthesis, however, data regarding patient satisfaction after the metal ceramic dental prosthesisis scarce in the scientific literature. Conclusion: Satisfaction with the esthetic restoration depends on patient education and awareness. Age and education add to a person's experience and increase awareness with respect to better aesthetics. Keywords: Aesthetics; patient satisfaction; assessment; patient care, metal ceramic prosthesis

Marginal bone loss associated with unilateral free end mandibular implant supporting superstructures constructed with different occlusal schemes

AimsThis study was designed to evaluate the amount of bone resorption related to implant in free end saddle in response to different occlusal designs.Patients and methodsTwenty patients with unilateral free end saddle in the lower arch till the second premolar were selected and received delayed single dental implants replacing the first molar tooth. They were divided into two main groups according to the implant superstructure deign (n = 10). Group 1: implant-supported fixed dental prosthesis which follow the principals of implant protected occlusion, and with the occlusal contact area of the crown smaller than the occlusal contact area of adjacent tooth. Group 2: implant-supported fixed dental prosthesis which follow the principals of implant protected occlusion, and with the occlusal contact area of the crown larger than the occlusal contact area of adjacent tooth. Patients were evaluated for the amount of marginal bone level at the time of crown insertion, after 3 and 6 months of function.ResultsThere was a statistically significant change by time in marginal bone loss in both groups especially during the first 3 months. However, there was no statistically significant difference between marginal bone loss regarding the two groups.ConclusionIt was concluded that increasing the occlusal contact area of the implant superstructure has no effect on marginal bone loss.

Grouping behaviour impacts on the parasitic pressure and squamation of sharks.

The evolution of grouping behaviour involves a complex trade-off of benefits and costs. Among the latter, an increase in the risk of parasitic transmission is a well-documented phenomenon that has likely promoted the evolution of defensive mechanisms in aquatic vertebrates. Here, we explore the relationship between grouping behaviour, parasitic richness (∼parasitic pressure), and the evolution of potential defensive traits in the squamation of sharks through phylogenetic, standard and zero-inflation regression models. Our results demonstrate that sharks that frequently aggregate show increased parasitic pressure, which may constitute an agent of selection. Accordingly, their squamation is characterized by large-scale crown insertion angles and low-scale coverage, which are interpreted as traits that compromise parasite attachment and survival. These traits are less evident in regions of the body and ecological groups that are subjected to high abrasive stress or increased drag. Thus, the squamation of sharks responds to a compromise between various functions, where protective and hydrodynamic roles prevail over the rest (e.g. ectoparasitic defence and bioluminescence aiding). This work establishes a quantitative framework for inferring parasitic pressure and social interaction from squamation traits and provides an empirical basis from which to explore these phenomena through early vertebrate and chondrichthyan evolution.

Esthetic and functional outcomes of narrow-diameter implants compared in a cohort study to standard diameter implants in the anterior zone of the maxilla.

The aim of this study was to evaluate functional and esthetic clinical outcomes and patient satisfaction with narrow-diameter implants in comparison to standard-diameter implants in the anterior zone of the maxilla in a follow-up examination after 1 to 6 years. The study was designed as a retrospective cohort study investigation including 27 patients receiving a 3.3-mm diameter single implant (NDI, n = 14) or a standard-diameter 4.1-mm single implant in the anterior zone of the maxilla (SDI, n = 16). Descriptive and analytical statistics were performed comparing both groups with regard to clinical examination including esthetic outcome, sulcus fluid flow-rate, crown esthetics, patients' satisfaction on visual analog scales, occurrence of biologic or technical complication, probing pocket depths (Fisher exact test), pink esthetic score (PES) and Periotest (Mann-Whitney U test). The level of significance was set at α = .05. The mean observation period was 4.8 years after crown insertion in the NDI group, and 4.9 years in the SDI group. Significant differences were observed for Periotest values in favor of the 4.1-mm implants (P = .014). No differences were found with regards to esthetics (PES; P = .27) or sulcus fluid flow-rate (P = 0.73) and probing pocket depths (P = .35). Overall patient satisfaction was high for both groups with visual analog scale scores of 9.3 ± 1.1 for NDI and 9.4 ± 1.0 for SDI (P = .39). Clinical outcome with narrow-diameter implants was comparable to standard-diameter implants in the anterior zone of the maxilla with similar esthetic assessments and patients' satisfaction.

Cemented versus screw-retained zirconia-based single-implant restorations: 5-year results of a randomized controlled clinical trial.

ObjectivesTo compare cemented and screw‐retained one‐piece zirconia‐based restorations in terms of clinical, radiographic, and technical outcomes 5 years after insertion.Materials and methodsThirty‐four patients with single‐tooth implants were randomly restored with either a cemented lithium disilicate crown on a one‐piece customized zirconia abutment (CEM, 17 patients) or a screw‐retained crown based on a directly veneered one‐piece customized zirconia abutment (SCREW, 16 patients). All patients were recalled for a baseline examination (7–10 days after crown insertion) and then annually up to 5 years. The following outcomes were assessed: marginal bone level (changes), technical, and clinical (bleeding on probing, plaque control record, probing depth, and keratinized tissue) parameters. The Mann–Whitney U‐test was used to assess differences between the two groups.ResultsAt 5 years, 26 patients (13 in each group) were re‐examined. The survival rates on the implant and restorative levels were 100% and 82.4% (equally for both groups), respectively. At 5 years, the median marginal bone level was located at −0.15 mm (IQR: −0.89 mm; 0.27 mm) (CEM) and −0.26 mm (IQR: −0.38 mm; 0.01 mm) (SCREW) below the implant shoulder (intergroup p = .9598). The median changes between baseline and the 5‐year follow‐up amounted to −0.23 mm (CEM; intragroup p = .0002) and −0.15 mm (SCREW; intragroup p = .1465) (intergroup p = .1690). The overall technical complication rate at 5 years was 15.4% (CEM) and 15.4% (SCREW) (intergroup p = 1.00). Clinical parameters remained stable over time (baseline to 5 years).ConclusionsAt 5 years, screw‐retained and cemented restorations rendered largely the same clinical, technical, and radiographic outcomes. Technical complications were frequent in both groups.

Perbandingan Pemasangan Implan Dental Single-Tooth Loss: Faktor Risiko dan Penyulit

Background: Edentulous cases or missing teeth is one of the problems complained about by patients in daily dental practice. Missing teeth are mostly discovered in adult patients, especially in posterior teeth such as premolar and molar. Nowadays, dental implant restoration in posterior single-tooth loss cases has been stated as the best treatment option. Nevertheless, hypertension is one of the risk factors that might cause difficulties in the dental implant procedure. Purpose: to compare the insertion of a dental implant in single-tooth loss between a patient without any systemic disease and a patient with a history of hypertension, using the same dental implant system and in the same timeframe. Case and Procedure: Case # 1, female patient age 43 years old came to RSGM-P FKG Usakti to have a dental implant insertion in the lower right posterior region. There was an absence of system disease in this patient. There were no difficulties during the dental implant insertion in tooth 46, therefore the osseointegration occurred nicely and the restorative crown insertion was precisely inserted. Case # 2, male patient age 49 years old with a chief complaint of missing tooth in the lower left posterior region, wanted to have a dental implant insertion. The patient had a history of hypertension with a regular daily intake of Amlodipine 5 mg once a day. Osseointegration occurred well after the dental implant insertion in tooth 35. However, during the screw uncovering stage, there was bone growth covering the surface of the cover screw. Therefore, removal of the bone growth should be done by using a round bur. In the impression-taking stage, there was slight gingival enlargement or overgrowth that almost covered the path of crown insertion. Gingivectomy had to be done before taking the impression in order to achieve precise crown insertion. The risk factor in the second case is that the patient consumed Amlodipine 5 mg daily, which causes overgrowth of bone and soft tissue surrounding the cover screw and implant fixture. Conclusion: There are differences in the outcome of the dental implant insertion in a patient without systemic disease and a patient with a history of hypertension with a daily intake of Amlodipine 5 mg medication; the factor that caused difficulties in the prosthetic stage is the presence of the alveolar bone and soft-tissue overgrowth.

Peri-implant tissue changes at sites treated with alveolar ridge preservation in the aesthetic zone: Twenty-two months follow-up of a randomized clinical trial.

To compare tissue changes at implant sites previously treated with two biomaterials for alveolar ridge preservation (ARP) in the aesthetic zone, 1 year after restoration. Sixty-six participants were treated with ARP using demineralized bovine bone mineral (DBBM) or DBBM +10% of collagen (DBBM-C), both covered with a collagen matrix (CM). Dental implants were placed, and definitive crowns were installed. Silicon impressions were taken before tooth extraction (T0), 2 weeks after crown insertion (T1) and 1 year after restoration (T2). Mid-facial mucosal level change (MLC), soft tissue thickness changes (TT), and marginal bone loss (MBL) were analysed using inter-group comparisons. Fifty-four participants were included in the analysis. The mid-facial level change between T0-T1 and T1-T2 showed no statistical difference between DBBM and DBBM-C. Between T0 and T1 for soft tissue thickness, DBBM performed significantly better at 3 and 5 mm below the mucosal margin. From T1 to T2, no significant differences between groups were found at any level for soft tissue thickness and MBL. At the aesthetic zone, advanced recession from tooth extraction to crown placement can be expected at sites treated with ARP regardless of biomaterial used. However, after crown insertion, tissue stability can be predicted.

Implant Placement With Graftless Sinus Floor Elevation via the Lateral Approach: A Case Series With 4 Years Post-Loading Radiographical Outcomes and Implant Survival Rate.

The purpose of the present study was to evaluate the radiographical outcomes, survival rate, and amount of bone formation around implants placed during graftless lateral sinus lift approach (GLSLA). Five patients (6 sinus augmentations) were consecutively treated with GLSLA. After Schneiderian membrane elevation and implant insertion, only blood clot was left to fill the new sinus compartment. After 4 months of healing, implants were functionally loaded. in all cases, samples were taken for biopsy at the time of second-stage surgery. The radiographical marginal bone variations and apical bone gain were assessed using cone beam- computed tomography taken 4 months after the surgery (at crown insertion) and after 4 years of loading. A total of 14 implants were placed in a mean initial residual bone height of 3.1 mm (range 1.64 mm). No failure was recorded, and all the implants were successfully loaded yielding a 100% survival rate. Vital bone formation was 33% according to the histomorphometry data. Four years after loading the mean radiographic bone remodeling was 1.3 mm. The mean ridge height was 7.6 mm and the mean apical bone gain amounted for 3.8mm. Within the limitations of this study, the placement of dental implants in conjunction with GLSLA seems to be feasible and accompanied by high implant survival rate.

Baseline selection for evaluation of peri-implant soft tissue changes: a clinical trial

BackgroundTo select the optimal baseline for evaluation of peri-implant soft tissue changes among 1, 2, and 3 weeks after definitive crown insertion.MethodsA total of 22 individuals who required implant restoration were recruited to this study. Each participant received a screw-retained conventional implant restoration. Peri-implant soft tissue was captured by an intraoral scanner and analyzed by 3D analysis software. Soft tissue changes [mucosal margin (MM) and soft tissue thickness (STT)] on the buccal side of implant sites were evaluated at 1, 2, and 3 weeks after definitive crown insertion. One-way analysis of variance (ANOVA) for repeated measurement and Tukey’s test were used to analyze significant differences between the 3 time points (α=0.05).ResultsAn increased volume of peri-implant soft tissue was observed shortly after definitive crown insertion. Based on the findings of peri-implant soft tissue changes, significant differences were observed between weeks 1 and 2 (P<0.01), and weeks 1 and 3 (P<0.01), while there was no significant difference between weeks 2 and 3 (P>0.05).ConclusionsMinimal peri-implant soft tissue changes occurred in this study. The time point of 2 weeks after definitive crown insertion was preliminarily selected as the baseline. The small sample size and few time points must be taken into consideration when interpreting these findings.Trial RegistrationThis study was retrospectively registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2000037954; Date of registration: 6 September 2020).

Primary bone augmentation leads to equally stable marginal tissue conditions comparing the use of xenograft blocks infused with BMP‐2 and autogenous bone blocks: A 3D analysis after 3 years

ObjectivesTo test whether or not primary bone augmentation using xenograft blocks infused with BMP‐2 or autogenous bone blocks lead to similar results regarding the implant survival and 3D marginal soft tissue contours.MethodsTwenty‐four patients with an insufficient ridge width for implant placement in need of primary augmentation were randomly assigned to either a block of deproteinized bovine bone mineral infused with rhBMP‐2 (BMP) or an intraorally harvested block of autogenous bone (ABB). At 4 months, 1–4 dental implants were placed in the regenerated area. After crown insertion and at 3 years, peri‐implant tissue parameters, two‐ and three‐dimensional radiographic parameters, and soft tissue contour changes were evaluated. Explorative mixed model analyses were performed. The level of significance was set at 5%.ResultsAt the 3‐year follow‐up, 23 patients with 40 implants were evaluated. The implant survival rate was 100% in both groups. At baseline, the marginal hard tissue levels amounted to −0.4 ± 0.8 mm (mean ± standard deviation) in the BMP group and −0.7 ± 1.0 mm in the ABB group. At 3 years, these values were −0.2 ± 0.4 mm (BMP) and −0.6 ± 1.0 mm (ABB). At baseline, the thickness of the buccal hard tissue at the level of the implant shoulder measured 1.1 ± 1.1 mm (BMP) and 1.4 ± 1.0 mm (ABB). At 3 years, it measured 0.9 ± 0.9 mm (BMP) and 0.7 ± 0.6 mm (ABB).ConclusionsThe present study demonstrated excellent implant survival rates and stable marginal hard tissue levels in both augmentation groups, 3 years after crown insertion. In addition, the clinical stability of soft and hard tissues was demonstrated in both groups.

CROWN MORPHOMETRY FOR TWO VALUABLE TIMBER SPECIES FROM MIOMBO WOODLAND IN MOZAMBIQUE

Pterocarpus angolensis DC and Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. &amp; Wiersema are two hardwood species found in Miombo woodland. Crown size, being closely related to the photosynthetic capacity of a tree, is an important parameter in studies of the growth of individual trees. In this sense, the present study aimed to study the morphometric relationships of P. angolensis and B. madagascariensis as a resource to describe the morphometric features of these species. Data were sampled in 60 rectangular plots of 20 x 50 m, systematically distributed within the forest. In each plot, the diameter at breast height (DBH), height (h), crown insertion point (cih) and four crown radii of all trees with DBH ≥ 10 cm were measured. Results indicated that crown diameter and crown length of P. angolensis grow as DBH and height increase, the larger the crown, the greater the trees dimensions; as for B. madagascariensis, crown features have shown low correlation when considering DBH. It was concluded that crown features influence on tree growth and are important measures of description and planning of silvicultural activities to be performed in natural forests. The results are of interest to forest managers since they make decisions about silvicultural operations. Keywords: crown dimensions; prediction models; umbila; pau-ferro; forest management.

Implants sites with concomitant bone regeneration using a resorbable or non-resorbable membrane result in stable marginal bone levels and similar profilometric outcomes over 5years.

To assess clinical and radiographic outcomes as well as the profilometric contour alterations of peri-implant hard and soft tissues around single implants treated with simultaneous guided bone regeneration (GBR) at 5years. Twenty-seven patients presenting with a single tooth gap in the esthetic zone received a two-piece implant. GBR was randomly performed using a resorbable (RES) or a non-resorbable membrane (N-RES) combined with a bone substitute material. Follow-up examinations were performed at baseline (BL=crown insertion), 1year (FU-1), 3years (FU-3), and at 5years (FU-5) including clinical and radiographic parameters as well as profilometric changes. Statistics were performed by means of parametric and nonparametric tests. At 5years, 20 out of 27 patients (9 RES, 11N-RES) were re-examined. Median values for probing depth changed insignificantly between BL and FU-5 in both groups. The median marginal bone levels were located 0.23mm (0.06; 0.46; RES) and 0.17mm (0.13;0.28; N-RES) below the implant shoulder at FU-5 (changes over time p<.05). The calculated median profilometric change between BL and FU-5 was -0.28mm (-0.53;-0.20; RES; p=.016) and -0.24mm (-0.43;0.08; N-RES; p=.102; intergroup p=.380). The horizontal bone thickness decreased significantly between re-entry and FU-5 for group RES at all measured levels (p<.05) measuring 0.87mm (0.0; 2.05) at the implant shoulder, whereas the decrease for group N-RES was insignificant (p=.031) with 0mm (0; 0.84) at the implant shoulder at 5years. Implants sites with concomitant GBR using a resorbable or non-resorbable membrane revealed stable marginal bone levels and clinical outcomes. Profilometric changes were clinically negligible over 5years. The observed change in hard tissue thickness was partially compensated by an increase in soft tissue thickness.

Implants Placed in Adolescents Followed for Up to 15.5 Years: A Retrospective Case Series.

To evaluate the clinical outcomes of unsplinted implant-supported single crowns placed in adolescents, ages 10 to 19 years, and followed up from 5 to 15 years. This retrospective case series evaluated the outcomes of implant-supported single crowns placed in adolescents between June 2002 and January 2015. The patients were treated with locking-taper connection implants under a two-stage rehabilitation technique. The variables assessed included patient identification, age and reason for implant placement, implant dimensions, follow-up time, status at follow-up, and event description. To analyze peri-implant changes, bone crest level relative to the adjacent tooth was measured from periapical radiographs taken after implantation and the latest follow-up. A paired t test was performed to determine initial and follow-up differences, and data are shown as mean and 95% confidence interval. Cumulative Kaplan-Meier survival rates for implants and prostheses were calculated. Twenty-one adolescent patients with ages ranging from 14 to 19 years, mainly 16 to 18 years, received a total of 37 implant-supported single crowns more frequently placed in the anterior maxilla as a result of congenital aplasia and trauma. Mean changes in bone crests were 1.99 (± 0.4) mm at the day of crown insertion and 2.23 (± 0.4) mm at the latest follow-up (average: 10 years; P = .08). No implant was lost during the follow-up period, leading to 100% implant survival. A total of 34 surviving crowns and 3 crown failures at the time of the latest follow-up led to a cumulative survival rate of 70%. The most commonly observed event was loss of proximal contacts and infraocclusion, which were handled chairside by adding resin composite. Unsplinted implant-supported single crowns placed in adolescents showed high implant and prosthesis survival rates, with a mean bone crest level increase of approximately 0.23 mm relative to the adjacent teeth.