Long-Term Follow-Up of Turned Single Implants Placed in Periodontally Healthy Patients After 16 to 22 Years: Microbiologic Outcome

Screw loosening in angulation-correcting single implant restorations: A systematic review of in vitro studies

STATEMENT OF PROBLEM

Various options are available to allow angle correction for screw-retained restorations for malaligned implants, including angled abutments, angled screw channel abutments, and angled implants. However, the effect these angle correction components have on prosthetic screw loosening is unclear.

PURPOSE

The purpose of this systematic review was to assess the effect of angled abutments, angled screw channel abutments, and angled implants on prosthetic screw loosening.

MATERIAL AND METHODS

This manuscript followed the Preferred Reporting Items for the Systematic Review and Meta-Analyses (PRISMA) statement. Searches were performed through 31 December 2021 in PubMed/MEDLINE, EMBASE, and Web of Science with no year limit targeting in vitro studies evaluating the effect of angulation correction components on screw loosening.

RESULTS

A total of 460 articles were identified. After removing duplicates, 306 titles were screened. Nine of the remaining 36 articles selected for full-text analysis met the selection criteria. The qualitative analysis used data from 394 implants. All studies featured straight abutments as the control group, and, in 8 studies, the angle correction component was included on the level of the abutment. Only in 1 study was the angle correction component at the level of the implant. The angle correction of the prosthetic component varied from 0 degrees in all studies up to a maximum correction of 30 degrees. Statistically significant increases in screw loosening with increasing abutment angle correction were reported by multiple authors (P<.05). However, other articles reported nonsignificant differences in screw loosening because of angulation after cyclic loading (P>.05). The only study investigating angle correction at the implant level found significantly less screw loosening (P<.05) in the angled implant group compared with the nonangled implant group.

CONCLUSIONS

Several options are available to correct discrepancies between the surgical axis and the ideal prosthetic axis for rehabilitations supported by dental implants. The current evidence does not clearly indicate the superiority of any single solution for minimizing screw loosening.

Do Concurrent Peri-Implantitis and Periodontitis Share Their Microbiotas? A Pilot Study

The microbial compositions from concurrent peri-implant and periodontal lesions were compared, since the results reported in the literature on the etiological relationship between these oral pathologies are contradictory. Microbial compositions from nine patients were evaluated using Illumina MiSeq sequencing of 16S rRNA gene amplicons and Principal Components Analysis. Comparisons between the use of curettes or paper points as collection methods and between bacterial composition in both pathologies were performed. Paper points allowed the recovery of a higher number of bacterial genera. A higher bacterial diversity was found in peri-implantitis compared to periodontal samples from the same patient, while a greater number of operational taxonomic units (OTUs) were present in the corresponding periodontal samples. A higher abundance of oral pathogens, such as Porphyromonas or Treponema, was found in peri-implantitis sites. The opposite trend was observed for Aggregatibacter abundance, which was higher in periodontal than in peri-implantitis lesions, suggesting that both oral pathologies could be considered different but related diseases. Although the analysis of a higher number of samples would be needed, the differences regarding the microbial composition provide a basis for further understating the pathogenesis of peri-implant infections.

Single crowns on tooth root-resected molars: A retrospective multicentric study

STATEMENT OF PROBLEM

Data regarding single restorations on molars treated with root resection and separation are limited.

PURPOSE

The purpose of this retrospective study was to evaluate the clinical success and survival of single crowns on root-resected molars.

MATERIAL AND METHODS

Eighty-six molars were treated with root resection or hemisection, prepared with feather-edge margins and restored with single crowns in 73 patients. The patients were clinically evaluated during regular recall appointments in 2018. Data were analyzed with descriptive statistics.

RESULTS

The mean follow-up time was 88.7 months (standard deviation, 70.6; range, 6 to 284). Six failures were recorded during the observation period, with a cumulative survival rate of 93%.

CONCLUSIONS

In this retrospective evaluation, single crowns on root-resected molars with feather-edge margins had clinical outcomes similar to those reported for single crowns on implants in the molar area. First molars and molars with 2 retained roots showed a better survival rate than second molars.

Experimental mucositis/gingivitis in persons aged 70 or over: microbiological findings and prediction of clinical outcome

OBJECTIVES

To assess in persons aged 70 years or older the microbiological alterations occurring around implants and natural teeth during and after 3 weeks of undisturbed plaque accumulation. Furthermore, to test the predictive value of several markers at baseline for the extent of inflammation around implants and teeth after this period.

MATERIALS AND METHODS

Twenty partially edentulous participants with titanium implants refrained from oral hygiene practices while being clinically monitored in weekly intervals for 21 days. Teeth and implants were then cleaned, oral hygiene resumed, and the participants were further monitored. Levels of six subgingival plaque microorganisms, the plaque index (PI), and the gingival index (GI) were assessed before (baseline), during (days 0, 7, 14, 21), and after plaque accumulation (days 28, 42). Six microorganisms; demographic and clinical variables at day 0 were further evaluated as potential predictors for presence of GI > 1 at days 21 and 28.

RESULTS

The detection frequency of the selected bacteria did not differ between implants and teeth at any time point. Bacteria counts decreased in the preparatory phase and increased in the plaque accumulation phase. Patterns observed at implants and teeth were similar. Only Parvimonas micra at day 21 reached significantly higher counts at implants than teeth. For the prediction of clinical outcome at day 21, in the multivariable model, only implant vs. tooth was significant indicator for the primary outcome (p = 0.01).

CONCLUSIONS

Overall, the analysis of subgingival/submucosal samples revealed only minor differences between implants and teeth during the development and resolution of inflammation.

CLINICAL RELEVANCE

Within the limitations of our study, with plaque accumulation, elders develop more inflammation around implants than around teeth, in spite of similar bacterial profiles.

Additive manufacturing of titanium alloy could modify the pathogenic microbial profile: an in vitro study

Additive manufacturing (AM) is an emerging process for biomaterials and medical devices. Direct Laser Metal Sintering (DLMS) is an AM technique used to fabricate Ti-6Al-4V implant materials with enhanced surface-related properties compared with wrought samples; thus, this technique could influence microbial adsorption and colonization. Therefore, this in vitro study was conducted to evaluate the impact of different implant production processes on microbial adhesion of periodontal pathogens. Titanium discs produced using two different processes-conventional and AM-were divided into three groups: conventional titanium discs with machined surface (G1), AM titanium discs with chemical treatment (G2) and AM titanium discs without chemical treatment (G3). Subgingival biofilm composed of 32 species was formed on the titanium discs, and positioned vertically in 96-well plates, for 7 days. The proportions of microbial complexes and the microbial profiles were analyzed using a DNA-DNA hybridization technique, and data were evaluated using Kruskal-Wallis and Dunnett tests (p < 0.05). Lower proportions of the red complex species were observed in the biofilm formed in G2 compared with that in G1 (p < 0.05). Moreover, the proportions of the microbial complexes were similar between G2 and G3 (p > 0.05). Compared with G1, G2 showed reduced levels of Porphyromonas gingvalis , Actinomyces gerencseriae, and Streptococcus intermedius , and increased levels of Parvimonas micra , Actinomyces odontolyticus, and Eikenella corrodens (p < 0.05). The microbial profile of G3 did not differ from G1 and G2 (p > 0.05). The results of this in vitro study showed that titanium discs produced via AM could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm these findings.

Detection of T. forsythia and other important bacteria in crestal and subcrestal implants with ligature-induced peri-implant infection in dogs

BACKGROUND

The study was designed to compare peri-implant microbial colonization of inflamed implants placed at different levels in dogs.

METHODS

Two screwed-in (SI) and two tapped-in (TI) conical connection implants were placed on each side of mandibles in six dogs respectively. Four experimental groups were constituted according to implant types and placement depth in one side: SI crestally (SIC), SI 1.5 mm subcrestally (SIS), TI crestally (TIC), and TI 1.5 mm subcrestally (TIS). Plaque accumulation of implants was promoted by cotton ligatures at either side randomly selected in each dog four weeks after abutment connection. Peri-implant sulcular fluid (PISF) samples were collected at 4 weeks, 10 weeks, and 16 weeks after abutment connection. Common periodontal pathogens in PISF were analyzed by PCR and realtime-PCR to investigate the influence of placement depth on microbial accumulation. The microbial results were further correlated with clinical parameters.

RESULTS

At ligatured sides, detection rates of T. forsythia and P. gingivalis increased significantly in four groups. T. forsythia levels increased significantly from baseline in four groups at ligatured sides at 16 weeks (p < 0.05). TIS group harbored significantly more T. forsythia than TIC at ligatured sides at 16 weeks (p < 0.05). At ligatured sides, probing depth was correlated to T. forsythia level in four groups as well as in total.

CONCLUSIONS

Subcrestal placement could increase the peri-implant T. forsythia level at the early stage of peri-implantitis. The T. forsythia level in the peri-implant sulcus is associated with probing depth.

Orthodontic Canine Substitution for the Management of Missing Maxillary Lateral Incisors May Have Superior Periodontal and Esthetic Outcomes Compared to an Implant- or Tooth-Supported Prosthesis

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Prosthetic replacement vs space closure for maxillary lateral incisor agenesis: A systematic review. Silveira GS, Almeida NV, Pereira DMT, Mattos CT, Mucha JN. Am J Orthod Dentofacial Orthop 2016; 150(2):228-37.

SOURCE OF FUNDING

None listed TYPE OF STUDY/DESIGN: Systematic review.

Initial and long-term crestal bone responses to modern dental implants

Successful osseointegration is the result of a controlled foreign body reaction to dental implants. Osseointegrated implants have demonstrated excellent long-term survivability, although they may be subject to limited marginal bone loss. Marginal bone loss during the first few years after implant placement seldom represents disease, but is instead the result of an adaptive bone response to surgical trauma and implant loading. It is not uncommon for implants with early marginal bone loss to enter a long-lasting state of bone stability. Extensive bone resorption after the first year is generally due to an exacerbation of adverse body reactions caused by non-optimal implant components, adverse surgery or prosthodontics and/or compromised patient factors. Disease in the form of peri-implantitis is a late complication that affects some implants with suppuration and rapid loss of crestal bone, and is probably caused by bacterial pathogens and immunological reactions. Unfortunately, the literature is not consistent with respect to the type or magnitude of clinical implant problems, including how they are defined and diagnosed. If the peri-implantitis diagnosis is confined to cases with infection, suppuration and significant bone loss, the frequency of the disease is relatively low, which is in sharp contrast to the frequencies reported with unrealistic definitions of peri-implantitis. We suggest that when modern implants are placed by properly trained individuals, only 1-2% of implants show true peri-implantitis during follow-up periods of 10 years or more. Peri-implantitis must be separated from the initial and self-limiting marginal bone loss.

Microbial Profiles and Detection Techniques in Peri-Implant Diseases: a Systematic Review

Objectives

To describe the microbial profiles of peri-implant diseases and the main detection methods.

Material and Methods

A literature search was performed in MEDLINE via PubMed database to identify studies on microbial composition of peri-implant surfaces in humans published in the last 5 years. Studies had to have clear implant status definition for health, peri-implant mucositis and/or peri-implantitis and specifically study microbial composition of the peri-implant sulcus.

Results

A total of 194 studies were screened and 47 included. Peri-implant sites are reported to be different microbial ecosystems compared to periodontal sites. However, differences between periodontal and peri-implant health and disease are not consistent across all studies, possibly due to the bias introduced by the microbial detection technique. New methods non species-oriented are being used to find ‘unexpected’ microbiota not previously described in these scenarios.

Conclusions

Microbial profile of peri-implant diseases usually includes classic periodontopathogens. However, correlation between studies is difficult, particularly because of the use of different detection methods. New metagenomic techniques should be promoted for future studies to avoid detection bias.

Transplant vs implant in a patient with agenesis of both maxillary lateral incisors: A 9-year follow-up

INTRODUCTION

Agenesis of a maxillary lateral incisor occurs in about 2% of the population. Treatment options should adapt to natural biologic changes in a lifelong perspective.

METHODS AND RESULTS

A young woman with bilateral agenesis of the maxillary lateral incisors was treated with transplantation of a developing maxillary third molar on one side and a dental implant on the contralateral side, after orthodontic space opening. The periodontal examination, including bacterial testing of the transplant, the implant, and the control central incisor, was performed 9 years after the treatment. A radiologic assessment was also performed. The transplanted tooth did not differ from a natural incisor, except for the pulp obliteration, and the total bacteria count was higher at the implant site. The periodontal tissues around the implant showed progressive signs of recession.

CONCLUSIONS

Both tooth transplants and dental implants for replacing missing maxillary incisors can be effective in the long term. This report supports natural tooth substitution rather than implant placement for dental agenesis in the anterior maxilla.