The effect of excess cement on peri-implantitis: A literature review

Peri-implantitis (PI) is a major dental implantology challenge. Excess cement (EC) significantly impacts PI onset and progression. This review clarifies unremoved EC's effects on peri-implant tissue. A literature search from 2012 to 2024 was conducted. Eleven studies examining EC's impact on peri-implant health were included. Investigated parameters were cement type, implant diameter, EC duration, and oral microbiota-cement interaction. Studies show EC as a key PI risk, with better outcomes post-removal. Larger implant diameters correlated with higher EC risks. EC retention duration directly affected PI severity. Different cements, like methacrylate-based cement (MeC) and zinc oxide and eugenol-based cement (ZOEC), varied in affecting PI. ZOEC notably mitigated PI risks and lacked in EC cases. Early PI detection and prompt removal are crucial. Choosing ZOEC cement can significantly reduce PI risks. Dentists should use minimal cement for implant restorations. Developing standard research methods is key to validate findings and guide practice.


Introduction
Implant-supported cemented prostheses (ICP) have gained attention due to their potential advantages over implantsupported screwed prostheses (ISP).These advantages encompass manufacturing simplicity and enhanced aesthetics, particularly as ICPs lack the visible prosthesis fixation screw canal (Chee et al., 2013;Fiorellini et al., 2019).Certain studies indicate increased resistance to occlusal loads in ICPs, credited to advanced ceramic layering and a denser metallic mass (Reda et al., 2022;Zaugg et al., 2018).Additionally, the reduced number of prosthetic components in ICPs might simplify occlusion control and make it more cost-effective (Frisch et al., 2016;Quaranta et al., 2017).However, a significant concern with ICPs is the high incidence of excess cement (EC) leakage into peri-implant tissues, reported in up to 60% of cases (Korsch et al., 2018;Linkevicius et al., 2013;Zaugg et al., 2018).Such leakage can lead to peri-implant disease (PID) and, in extreme cases, implant loss (Burbano et al., 2015;Reda et al., 2022).
Several factors contribute to EC occurrences.Notable among them are the termination position of the prosthetic crown, the implant diameter (ID), and the cement type (Ayyadanveettil et al., 2021;Korsch & Walther, 2015;Rohr et al., 2018;Romanos, 2019;Rotim et al., 2021).The location of crown terminations is pivotal; a deeper subgingival positioning increases the challenge of identifying and removing EC (Linkevicius et al., 2013;Zeinabadi et al., 2020).The ID also plays a significant role, with the difficulty of EC removal increasing proportionally to the ID size.The choice of cement has garnered research attention due to factors such as its viscosity and radiolucency, which can impact EC formation, detection, and the potential for biofilm development near the peri-implant tissue (PIT) (Wadhwani & Piñeyro, 2009).Wilson et al. (2019) indicates a surge in peri-implant tissue inflammation-up to 81%-when EC is not thoroughly removed.This inflammation arises because the cement, as a foreign body, provides an ideal surface for plaque buildup (Zandim-Barcelos et al., 2019).Conversely, while numerous studies have highlighted the potential negative effects of EC on dental implants, excessive material has been linked to complications, including pain, aesthetic issues, bleeding on probing (BoP), suppuration (Su), and bone support loss (BL) (Fiorellini et al., 2019;Quaranta et al., 2017;Santiago Garzón et al., 2018).

Recent research by
This study aims to review the literature to elucidate the negative consequences of unremoved EC on PIT, with a goal of deepening clinicians' understanding of these effects.

Methodology
To conduct this review eligibility criteria were rigorously defined based on the PICOS (Participants, Interventions, Comparisons, Outcomes, and Study Design) framework.

Search strategy
This review was guided by the fundamental question: "What are the negative consequences of unremoved EC on PIT?" To address this inquiry, a comprehensive literature search was conducted across PubMed/Medline, Web of Sciences, Embase, Scopus, Cochrane Library, Lilacs, and Scopus databases, also a search on Google Scholar was conducted so gray literature could be included.The search strategy employed keywords such as 'cement ', 'dental', 'implant', and 'effect' and was limited to articles published between 2012 and 2024.Additional studies were identified through hand-searching the reference lists of included articles and reviews.

Eligibility criteria
Studies were imported into Mendeley (Reference Manager Software, Elsevier) for de-duplication.Inclusion and exclusion criteria were defined as follows based on the PICOS framework: • Participants: Human participants with implant-supported cemented prostheses.
• Interventions: Any type of cement used in dental implants.
• Comparisons: Comparisons between different types of cement or cemented vs. screw-retained prostheses.
• Study Design: Randomized and non-randomized clinical trials published in peer-reviewed journals.
Exclusion criteria included in vitro studies, animal studies, case reports, reviews, and studies focusing on other types of prostheses.

Data extraction
Two investigators (K.A.S.B and J.E.A.R) independently screened titles and abstracts against the eligibility criteria.Fulltext articles were then assessed for final inclusion.Data extracted from the studies included sample size, interventions applied, outcomes observed, and study design.Discrepancies at any stage were resolved through discussion, and a third investigator (P.R.M) was consulted when consensus could not be reached.

Article selection
The article screening process is visualized in Figure 1, which outlines the reasons for exclusions during each step.An initial set of 506 studies was retrieved from the database search.After reviewing titles and abstracts, 68 studies were identified as relevant and cataloged in Mendeley software.Following this, KS and JA closely examined the 68 studies, scrutinizing their abstracts and applying the predefined inclusion and exclusion criteria.This in-depth evaluation resulted in the selection of 10 articles suitable for this review.Each of these articles then underwent a quality assessment.
Separately, JS conducted a manual search, identifying an additional article that met the inclusion criteria.As a result, the total number of studies included in this review stands at 11.

Relationship between screw-retained and cement-retained prostheses and peri-implant disease
In a study by Kotsakis et al. (2016), the relationship between the type of ICP and PID was explored through an examination of 135 participants.Of this group, 31 had partial coverage restorations using zinc oxide and eugenol-based cement (ZOEC), while 83 opted for full-coverage ICPs.An intraoral clinical examination (ICE) assessed the presence of BoP, probing depth (PD), and the oral hygiene index (OHI).Based on these findings, participants were divided into two groups: those with healthy PIT and those showing signs of diseased PIT.
Among the ISP users, 64 individuals (77.11%) showed signs of PID.Conversely, in the ZOEC group, 25 participants, or 80.65%, displayed PID symptoms.However, despite these high percentages, there was no statistically significant difference between the ISP and ZOEC groups in the prevalence of PID.Kotsakis et al. (2016) suggested that, with thorough removal of excess cement, the use of partial coverage restorations does not compromise patients' peri-implant health.

Relationship between the presence of residual cement and peri-implant disease.
Numerous studies have investigated the link between residual EC in ICP and the development of PID.In this review, nine out of eleven articles specifically examined this relationship.Across these studies, 777 crowns were removed from implants, with EC identified in an average of 61.5% (± 2.95%) of these cases.Afterward, these crowns were disinfected with chlorhexidine and cemented using zinc oxide and ZOEC.

Relationship between the implant diameter and the presence of excess cement.
Several factors can influence the presence of EC in PCIs.Exploring this, Korsch et al. (2015a) examined 126 PCIs, assessing for EC, BoP, Su, IL, BL, ID, and the specific cement type used.When comparing implant diameters, EC was found in 66.8% of larger-diameter implants.In contrast, regular and narrow-diameter implants showed EC rates of 59.1% and 45.2%, respectively.Based on these observations, the study suggests that an increase in ID is linked to heightened risks of EC, PID, and potential implant failure.

Relationship between the residence time of excess cement and the severity of pid.
The duration of EC retention within the PIT plays a role in PID progression.To explore this, Korsch and Walther (2015) studied 171 ICPs, all cemented using methacrylate-based cement (MeC).The sample was divided based on the intraoral duration of the cement: one group had shorter residence times and the other had longer residence times.During the ICE for each prosthesis, the presence of EC, BoP, and Su was recorded.Initial findings for the shorter duration group showed 60 cases (47.6%) with both BoP and EC and 16 cases (12.6%) with Su alongside EC.For the longer duration group, 28 cases (62.2%) displayed BoP and EC, while 25 cases (55.5%) showed Su in association with EC.The study concluded that the clinical inflammation indicators were related either to the duration of EC retention or its mere presence.

Types of cement and their behavior in pit
Following their initial ICE, Korsch and Walther (2015) proceeded with a non-surgical peri-implant treatment for all studied implants.All MeC residues were meticulously removed from the PCIs, which were then cemented with zinc oxide and ZOEC.A subsequent ICE showed a decline in BoP cases: nine implants in group 1 and eight in group 2. When compared with initial ICE findings, this represented a reduction of 74% and 71% in BoP manifestations for the respective groups.As for Su, group 1 showed a total reduction (100%), while group 2 had a decline of 88%.Based on these results, the study concluded that the presence of MeC was directly related to the onset of clinical symptoms indicative of PID.

Relationship between the oral microbiota and the different types of cement.
The influence of oral microbiota on different dental cements was investigated in two selected studies.In both studies, prostheses initially cemented with MeC were detached, and the presence of EC and Su was noted.After collecting a gingival fluid sample for analysis, the prostheses were recemented with ZOEC and later reassessed.
With the application of ZOEC, no instances of EC were observed.However, when MeC was used, Korsch et al. (2017) found EC in 40% (n =24) of their samples, and Korsch et al. (2018) reported a 60% (n=12) prevalence.Given ZOEC's lack of EC, determining its potential impact on the PIT became difficult.Still, the authors concluded that ZOEC, with its beneficial properties, appears suitable as a permanent cement for fixed dental restorations on implants.

Discussion
PI represents a significant challenge in contemporary dental practice due to its prevalence among dental implant patients (Kotsakis et al., 2016).This review sought to clarify the role of EC in the onset of PI and the correlation between EC presence and PI severity.Of the literature explored, studies consistently highlighted EC as a pronounced risk factor for PI, with its removal often leading to improved clinical outcomes (Korsch et al., 2015a;Korsch et al., 2015b;Korsch et al., 2017;Korsch et al., 2018).
This underscores the clinical imperative: when cementing restorations to implants, the use of minimal cement is advised to reduce PI risks (Korsch & Walther, 2015).
Furthermore, the relationship between the duration of EC retention and PI severity emerged as a focus.One study suggested that clinical markers of inflammation are associated with either the revision time or the presence of EC, highlighting the importance of swift EC revision and removal for effective PI management (Korsch & Walther, 2015).The preference for cements that allow seamless removal without damaging the implant or adjacent tissues is evident (Korsch et al., 2015a).
The cement type is pivotal in PI's onset.Comparisons between MeC and ZOEC highlighted distinct outcomes.The utilization of MeC was integral to the clinical symptoms indicative of PI, while ZOEC's adoption correlated with a marked reduction in PI severity (Korsch et al., 2017;Korsch et al., 2018).Given this distinction, dental practitioners are advised to prefer ZOEC to mitigate PI risks (Linkevicius, et al., 2013).
Additionally, the interplay between oral microbiome and cement type in PI's development was assessed.Findings from two studies revealed the absence of EC when ZOEC was used, contrasting with its presence in MeC cases (Korsch et al., 2017;Korsch et al., 2018).The nonexistence of EC with ZOEC suggests its benign nature regarding implant health, although further investigations are needed for a definitive stance.Nonetheless, ZOEC's adoption as a favored permanent cement is recommended, given its efficacy in fixed dental implant restorations (Terra et al., 2019).
It's paramount to acknowledge this review's constraints.Solely focusing on English-language publications might omit significant studies in other languages.Furthermore, the variability in sample sizes, longitudinal follow-ups, and treatment protocols across the studies might introduce outcome disparities.This highlights the need for future research with standardized methodologies to validate the insights presented (Page et al., 2021).

Conclusion
To conclude, this review illuminates the salient role of EC as a key risk determinant for PI onset, underscoring the clinical benefits of its timely removal.Both the cement's classification and the duration of EC presence significantly influence PI's evolution.Dental practitioners are advised to use minimal cement quantities during implant restoration procedures and to give preference to ZOEC to reduce PI susceptibility.Further rigorous investigations are paramount to reaffirming these conclusions and crafting standardized modalities for efficacious PI management.
Therefore, to advance PI research, future studies should focus on: • Multi-center trials to assess the long-term effects of cement types on peri-implant health.
• Development and evaluation of new cements and removal techniques to prevent peri-implantitis.
• Creation of standardized clinical guidelines for optimal cement use in implantology.

Figure 1 -
Figure 1 -Screening of the studies.

Table 1 -
Screening of the studies.