Peri-implant health, peri-implant mucositis, and peri-implantitis: Case definitions and diagnostic considerations.

The objective of this review is to identify case definitions and clinical criteria of peri-implant healthy tissues, peri-implant mucositis, and peri-implantitis. The case definitions were constructed based on a review of the evidence applicable for diagnostic considerations. In summary, the diagnostic definition of peri-implant health is based on the following criteria: 1) absence of peri-implant signs of soft tissue inflammation (redness, swelling, profuse bleeding on probing), and 2) the absence of further additional bone loss following initial healing. The diagnostic definition of peri-implant mucositis is based on following criteria: 1) presence of peri-implant signs of inflammation (redness, swelling, line or drop of bleeding within 30 seconds following probing), combined with 2) no additional bone loss following initial healing. The clinical definition of peri-implantitis is based on following criteria: 1) presence of peri-implant signs of inflammation, 2) radiographic evidence of bone loss following initial healing, and 3) increasing probing depth as compared to probing depth values collected after placement of the prosthetic reconstruction. In the absence of previous radiographs, radiographic bone level ≥3 mm in combination with BOP and probing depths ≥6 mm is indicative of peri-implantitis.

Ligature-induced peri-implantitis and periodontitis in mice.

AIM: Peri-implantitis (PI), inflammation around dental implants, shares characteristics with periodontitis (PD). However, PI is more difficult to control and treat, and detailed pathophysiology is unclear. We aimed to compare PI and PD progression utilizing a murine model. MATERIALS AND METHODS: Four-week-old male C57BL/6J mice had their left maxillary molars extracted. Implants were placed in healed extraction sockets and osseointegrated. Ligatures were tied around the implants and second molars. Controls did not receive ligatures. Mice were sacrificed 1 week, 1 and 3 months (n ≥ 5/group/time point) post-ligature placement. Bone loss analysis was performed. Histology was performed for: haematoxylin and eosin (H&E), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-8 (MMP-8), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), toluidine blue and calcein. RESULTS: PI showed statistically greater bone loss compared to PD at 1 and 3 months. At 3 months, 20% of implants in PI exfoliated; no natural teeth exfoliated in PD. H&E revealed that alveolar bone surrounding implants in PI appeared less dense compared to PD. PI presented with increased osteoclasts, MMP-8 and NF-κB, compared to PD. CONCLUSION: PI exhibited greater tissue and bone destruction compared to PD. Future studies will characterize the pathophysiological differences between the two conditions.

Salivary exRNA biomarkers to detect gingivitis and monitor disease regression.

AIM: This study tests the hypothesis that salivary extracellular RNA (exRNA) biomarkers can be developed for gingivitis detection and monitoring disease regression. MATERIALS AND METHODS: Salivary exRNA biomarker candidates were developed from a total of 100 gingivitis and non-gingivitis individuals using Affymetrix's expression microarrays. The top 10 differentially expressed exRNAs were tested in a clinical cohort to determine whether the discovered salivary exRNA markers for gingivitis were associated with clinical gingivitis and disease regression. For this purpose, unstimulated saliva was collected from 30 randomly selected gingivitis subjects, the gingival and plaque indexes scores were taken at baseline, 3 and 6 weeks and salivary exRNAs were assayed by means of reverse transcription quantitative polymerase chain reaction. RESULTS: Eight salivary exRNA biomarkers developed for gingivitis were statistically significantly changed over time, consistent with disease regression. A panel of four salivary exRNAs [SPRR1A, lnc-TET3-2:1, FAM25A, CRCT1] can detect gingivitis with a clinical performance of 0.91 area under the curve, with 71% sensitivity and 100% specificity. CONCLUSIONS: The clinical values of the developed salivary exRNA biomarkers are associated with gingivitis regression. They offer strong potential to be advanced for definitive validation and clinical laboratory development test.

Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implantitis sites exhibit clinical signs of inflammation, bleeding on probing, and/or suppuration, increased probing depths and/or recession of the mucosal margin in addition to radiographic bone loss. The evidence is equivocal regarding the effect of keratinized mucosa on the long-term health of the peri-implant tissue. It appears, however, that keratinized mucosa may have advantages regarding patient comfort and ease of plaque removal. Case definitions in day-to-day clinical practice and in epidemiological or disease-surveillance studies for peri-implant health, peri-implant mucositis, and peri-implantitis were introduced. The proposed case definitions should be viewed within the context that there is no generic implant and that there are numerous implant designs with different surface characteristics, surgical and loading protocols. It is recommended that the clinician obtain baseline radiographic and probing measurements following the completion of the implant-supported prosthesis.

Salivary biomarkers in the diagnosis of periodontal diseases.

Periodontal diseases are considered some of the most prevalent diseases in the adult population, affecting as much as 80 percent of people. Diagnosis can be performed by measuring pocket depth and bleeding upon probing. These diseases can be easily addressed in their early stages, but many choose to ignore the signs and symptoms. Saliva has recently emerged as a potential tool to aid in the diagnosis of periodontal diseases and the prediction of treatment outcomes.

The Modified Apically Repositioned Flap Technique and Its Potential to Create Attached Gingiva in Areas with No Keratinized Tissue: A Long-Term (1 to 11 Years) Retrospective Case Series Study.

The modified apically repositioned flap (MARF) technique has been previously published as a successful method to increase the zone of attached gingiva with numerous advantages, such as simplicity, predictability, and long-term stability. However, this technique has only been used in areas with at least 0.5 mm of attached gingiva, presurgically. In the current study, the MARF technique was utilized in 21 sites (teeth) with no attached gingiva and only mucosa comprising the marginal tissue. The long-term follow-up results over the course of 1 to 11 years (average follow-up: 3.2 years) show a statistically significant increase of 3.6 ± 0.8 mm for keratinized tissue and of 2.21 ± 0.83 mm for attached gingiva, and no increases in probing depths or marginal tissue recession. These results indicate that the MARF procedure has generated keratinized tissue and attached gingiva in areas with a presurgical absence of these tissues.

A surgical reentry study on the influence of platelet-rich plasma in enhancing the regenerative effects of bovine porous bone mineral and guided tissue regeneration in the treatment of intrabony defects in humans.

BACKGROUND: The purpose of this study was to evaluate the additional benefits provided by the incorporation of platelet-rich plasma (PRP) into a regenerative protocol consisting of bovine porous bone mineral (BPBM) and guided tissue regeneration (GTR) in the treatment of intrabony defects in humans. METHODS: Twenty-three paired intrabony defects were surgically treated using a split-mouth design. Defects were treated with BPBM/GTR/PRP (experimental group) or with BPBM/GTR (control group). The clinical parameters evaluated included changes in probing depth, clinical attachment level, and defect fill as revealed by reentry surgeries at 6 months. RESULTS: Preoperative probing depths, attachment levels, and transoperative bone measurements were similar for the two groups. Post-surgical measurements taken at 6 months revealed that both treatment modalities resulted in a significant decrease in probing depth, gain in clinical attachment, and bone fill of the defects compared to baseline. Postoperative differences observed between the two groups were 0.72 +/- 0.36 mm at buccal sites and 0.90 +/- 0.32 mm at lingual sites for probing depth, 0.82 +/- 0.41 mm at buccal sites and 0.78 +/- 0.38 at lingual sites for gain in clinical attachment, and 0.85 +/- 0.36 mm at buccal sites and 0.94 +/- 0.42 mm at lingual sites for defect fill, all favoring the experimental sites. However, none of the differences were statistically significant. CONCLUSION: Within the limitations related to using a small sample size, PRP did not significantly augment the effects of BPBM and GTR in promoting the clinical resolution of intrabony defects.

Rieger Syndrome: Rehabilitation With Dental Implants.

INTRODUCTION: Axenfeld-Rieger syndrome (ARS), also known as Rieger syndrome, is a rare autosomal dominant condition defined by craniofacial, ocular, dental, periumbilical, and systemic anomalies. CASE PRESENTATION: This case report describes in detail a multidisciplinary approach to successfully restore the oral function and esthetics of a 22-year-old patient diagnosed with ARS. The patient's clinical evaluation revealed that the area corresponding with teeth #13, #12, #11, #21, #22, and #23 was occupied by four malformed and/or deciduous teeth. The four anterior teeth were extracted, and socket preservation was performed using bovine-derived porous bone mineral. Six months after extractions, two implants were placed in the location of the lateral incisors and additional bone graft was performed. Two months after the initial healing, a temporary fixed partial was delivered and 9 months after implant placement the implants were restored with a porcelain-fused-to-metal fixed partial denture. CONCLUSIONS: The use of implant-supported fixed partial dentures to restore missing teeth in patients with ARS provides biological and mechanical advantages over conventional, fixed, or removable prosthodontics. Further evaluation is needed to determine the longevity and long-term prognosis of dental implants in patients with ARS.

Benign masseter muscle hypertrophy.

Idiopathic hypertrophy of the masseter muscle is a rare disorder of unknown cause. Some authors associate it with the habit of chewing gum, temporo-mandibular joint disorder, congenital and functional hypertrophies, and emotional disorders (stress and nervousness). Most patients complain of the cosmetic change caused by facial asymmetry, also called square face, however, symptoms such as trismus, protrusion and bruxism may also occur. The goals of the present investigation were: to report a case of idiopathic masseter hypertrophy, describe its symptoms and treatment. The patient reported bilateral bulging in the region of the mandible angle, of slow and progressive evolution. He did not complain of pain or discomfort, however there was bilateral otalgia, nighttime trismus and stress. In his physical exam we noticed bilateral masseter hypertrophy without local inflammatory alterations. We indicated surgical treatment with an extraoral approach. Complementary tests are indicated when there is diagnostic doubts. Treatment varies from conservative to surgical, and the later depends on surgeon skill and experience.

The Modified Apically Repositioned Flap Technique: A Long-Term (4 to 16 Years) Retrospective Study.

Attached gingiva is desirable for the maintenance of gingival health. Although many methods are used to increase the zone of attached gingiva, the modified apically repositioned flap (MARF) technique has the advantages of simplicity and predictability. The short-term follow-up of the MARF technique demonstrated an increase in keratinized tissue and attached gingiva. This study evaluated long-term results of the MARF technique as used to increase the apicocoronal dimensions of keratinized tissue and attached gingiva in 28 sites (25 patients; average follow-up of 9 years). There was a statistically significant increase in keratinized tissue and attached gingiva with no increase in probing depths or gingival recession. These results suggest that the MARF procedure predictably generates keratinized tissue and attached gingiva with long-term stability.

Peri-implant health, peri-implant mucositis, and peri-implantitis: Case definitions and diagnostic considerations.

The objective of this review is to identify case definitions and clinical criteria of peri-implant healthy tissues, peri-implant mucositis, and peri-implantitis. The case definitions were constructed based on a review of the evidence applicable for diagnostic considerations. In summary, the diagnostic definition of peri-implant health is based on the following criteria: 1) absence of peri-implant signs of soft tissue inflammation (redness, swelling, profuse bleeding on probing), and 2) the absence of further additional bone loss following initial healing. The diagnostic definition of peri-implant mucositis is based on following criteria: 1) presence of peri-implant signs of inflammation (redness, swelling, line or drop of bleeding within 30 seconds following probing), combined with 2) no additional bone loss following initial healing. The clinical definition of peri-implantitis is based on following criteria: 1) presence of peri-implant signs of inflammation, 2) radiographic evidence of bone loss following initial healing, and 3) increasing probing depth as compared to probing depth values collected after placement of the prosthetic reconstruction. In the absence of previous radiographs, radiographic bone level ≥3 mm in combination with BOP and probing depths ≥6 mm is indicative of peri-implantitis.

Genomewide Association Study Identifies Cxcl Family Members as Partial Mediators of LPS-Induced Periodontitis.

Periodontitis (PD) is characterized by bacterial infection and inflammation of tooth-supporting structures and can lead to tooth loss. PD affects ∼47% of the US population over age 30 years and has a heritability of about 50%. Although the host immunoinflammatory response and genetic background play a role, little is known of the underlying genetic factors. We examined natural genetic variation in lipopolysaccharide (LPS)-induced PD across a panel of inbred mouse strains, the hybrid mouse diversity panel (HMDP). We observed a strain-dependent sixfold difference in LPS-induced bone loss across the HMDP with a heritability of 53%. We performed a genomewide association study (GWAS) using FAST-LMM, which corrects for population structure, and identified loci significantly associated with PD. We examined candidate genes at a locus on chromosome 5, which suggested a relationship between LPS-induced bone loss and, together with expression data, identified Cxcl family members as associated with PD. We observed an increase in Cxcl10 protein, as well as immune cells and pro-inflammatory cytokines in C57BL/6J (high bone loss strain) but not in A/J (low bone loss strain) after LPS injections. Genetic deletion of CXCR3 (Cxcl9 and10 receptor) demonstrated a ∼50% reduction in bone loss and reduced osteoclasts after LPS injections. Furthermore, WT mice treated with AMG-487 (a CXCR3 antagonist) showed a ∼45% reduction in bone loss and decreased osteoclasts after LPS injections. We conclude that CXCR3 is a strong candidate for modulating the host response in individuals susceptible to PD. © 2018 American Society for Bone and Mineral Research.

Early intervention of peri-implantitis and periodontitis using a mouse model.

BACKGROUND: Peri-implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri-implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri-implantitis and periodontitis lesions after insult removal. METHODS: Implants were placed in one-month-old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature-retained and ligature-removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro-computed tomography and histology. RESULTS: By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri-implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri-implantitis and periodontitis ligature-retained groups and decreased following insult removal. Collagen was overall more disorganized in peri-implantitis than periodontitis for all groups. Peri-implantitis experimental groups revealed greater matrix metalloproteinase-8 and NF-kB levels than periodontitis. CONCLUSIONS: Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri-implantitis disease pathophysiology.

Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implantitis sites exhibit clinical signs of inflammation, bleeding on probing, and/or suppuration, increased probing depths and/or recession of the mucosal margin in addition to radiographic bone loss. The evidence is equivocal regarding the effect of keratinized mucosa on the long-term health of the peri-implant tissue. It appears, however, that keratinized mucosa may have advantages regarding patient comfort and ease of plaque removal. Case definitions in day-to-day clinical practice and in epidemiological or disease-surveillance studies for peri-implant health, peri-implant mucositis, and peri-implantitis were introduced. The proposed case definitions should be viewed within the context that there is no generic implant and that there are numerous implant designs with different surface characteristics, surgical and loading protocols. It is recommended that the clinician obtain baseline radiographic and probing measurements following the completion of the implant-supported prosthesis.

Increasing the apico-coronal dimension of attached gingiva using the modified apically repositioned flap technique: a case series with a 6-month follow-up.

BACKGROUND: This case series reports on the effectiveness of the modified apically repositioned flap (MARF) in increasing the apico-coronal dimension of attached gingiva over multiple adjacent teeth. METHODS: The MARF surgical technique consists of a single horizontal incision within keratinized tissue, elevation of a split-thickness flap, and suturing of the flap to the periosteum in an apical position. The periosteum is left exposed so that the full perimeter of the wound is surrounded by keratinized tissue. The nature of this wound healing leads to the formation of new keratinized and attached tissue in the area where periosteum is left exposed. A total of 37 areas in 33 systemically healthy patients were analyzed after treatment with the MARF technique. The treatment areas consisted of a minimum of two and a maximum of five adjacent teeth with a minimum of 0.5 mm and a maximum of 2.0 mm of attached gingiva on each tooth. RESULTS: Treatment with MARF resulted in a significant increase in the apico-coronal dimension of the keratinized tissue and attached gingiva (P <0.05). The increase in keratinized tissue ranged from 2.20 to 4.28 mm, and the increase in attached gingiva ranged from 1.0 to 3.14 mm. Gingival recession decreased significantly in the treated areas, but the difference was of little clinical significance. Probing depths in the treated areas did not change significantly compared to baseline values. CONCLUSIONS: MARF is an effective technique in increasing the apico-coronal dimension of the keratinized tissue and attached gingiva. MARF offers considerable advantages over other mucogingival surgery techniques: simplicity, limited chair time for the patient and the operator, low morbidity because of the absence of palatal donor tissue, and a predictable tissue color match.

Clinical crown lengthening in the esthetic zone.

Periodontal surgical procedures consisting of gingival flaps and osseous recontouring are indicated for crown lengthening of several contiguous teeth in the esthetic zone; both in cases where restorations are required and in cases where no restorations are planned, such as in patients with excessive gingival display due to altered passive eruption. Forced tooth eruption via orthodontic extrusion is the technique of choice when clinical crown lengthening is necessary on isolated teeth in the esthetic zone.

Use of the Modified Apically Repositioned Flap Technique to Create Attached Gingiva in Areas of No Keratinized Tissue: A Clinical and Histologic Evaluation.

The complete absence of keratinized attached gingiva on the buccal surface of a tooth can make the area more susceptible to gingival recession. The modified apically repositioned flap (MARF) technique is an effective procedure to increase the dimensions of attached gingiva in areas that present with some existing keratinized tissue. The objective of this case report is to present long-term clinical and histologic evidence that the MARF technique can be used to create attached gingiva in areas that lack keratinized tissue.

Comparing the Healing Potential of Late-Stage Periodontitis and Peri-Implantitis.

Peri-implantitis is defined as an inflammatory disease affecting the tissues around osseointegrated functioning implants. Unfortunately, detailed peri-implantitis pathogenesis is not well understood and current treatments lack predictability. Compare the healing potential of late-stage ligature-induced periodontitis and peri-implantitis after ligature removal. Four-week-old C57BL/6J male mice had their left maxillary molars extracted. After 8 weeks, implants were placed in healed sockets and allowed to osseointegrate. Mice were separated into control (no ligature) and experimental (ligature) groups. In the experimental group, ligatures were placed around the implant and the contralateral second molar. Four weeks later, the ligature group was randomly divided into ligature-retained and ligature-removed groups. Mice were sacrificed at 2 time points: 1 and 2 weeks after ligature removal. The samples were analyzed by microcomputed tomography (micro-CT) and histology. Ligature-induced significant bone loss in peri-implantitis and periodontitis were compared with respective controls. At the 2-week time point, bone formation was observed in the ligature-removed groups compared with respective controls; however, more bone was regained in periodontitis ligature-removed compared with the peri-implantitis ligature-removed group. Histologically, the peri-implantitis ligature-retained group had higher inflammatory levels and a higher number of osteoclasts compared with the periodontitis ligature-retained group. Moreover, in the peri-implantitis ligature-retained group, collagen appeared less organized compared with the periodontitis ligature-retained group at both time points; although collagen tended to reorganize following ligature removal in both conditions. Peri-implantitis does not respond to treatment as well as periodontitis. Future work includes understanding peri-implantitis pathogenesis and developing predictable treatment protocols.

Root coverage with a coronally positioned flap used in combination with enamel matrix derivative: 18-month clinical evaluation.

BACKGROUND: Ginigival recession can be successfully treated with coronally positioned flaps. Twelve-month data failed to demonstrate that topical application of enamel matrix derivative (EMD) used in combination with the coronally positioned flap enhances clinical outcomes of the surgical technique used alone. This study was designed to examine the effects of EMD combined with the coronally positioned flap over an 18-month postoperative period. METHODS: Thirty patients presenting with Miller Class I or II gingival recessions on single-rooted teeth participated in this parallel-design clinical study. Six weeks after phase I therapy, recession areas were surgically treated with a coronally positioned flap for root coverage. Teeth in the experimental group received EMD treatment of the exposed root, whereas control teeth did not. Clinical parameters evaluated at baseline and 18 months postoperatively included gingival recession, clinical attachment level, probing depth, and the apico-coronal dimension of the keratinized tissue. RESULTS: Compared to baseline, 18-month measurements showed a significant reduction in probing depth, gain in attachment level, and decrease in gingival recession for control and experimental groups. When the results of the two treatment groups were compared, the experimental group presented with significantly greater root coverage than the control group (2.66 +/- 0.61 mm versus 1.73 +/- 0.70 mm, respectively), more gain in clinical attachment than the control group (2.80 +/- 0.76 mm versus 2.06 +/- 0.70 mm, respectively), and a greater gain in the apico-coronal dimension of the keratinized tissue than the control group (0.13 +/- 0.06 mm versus -0.06 +/- 0.01 mm, respectively). CONCLUSION: The results of this study indicate that topical application of EMD is beneficial in augmenting the effects of the coronally positioned flap in terms of amount of root coverage, gain in clinical attachment, and in increasing the apico-coronal dimension of the keratinized tissue.

Prostanoid- and interleukin-1-induced primary genes in cementoblastic cells.

BACKGROUND: Cementum is a key component of a functional periodontal organ. However, regenerating lost cementum is difficult and often incomplete. Identifying molecular mediators of cementoblast differentiation and function should lead to better targeted treatment for periodontitis. Prostaglandins increase mineralization of murine cementoblastic OCCM cells and alveolar bone formation, whereas the cytokine interleukin-1 (IL-1) inhibits alveolar bone formation. We hypothesized that differentially induced primary genes in OCCM cells may mediate anabolic and catabolic responses. Our objective was to identify primary genes differentially induced by the synthetic prostanoid fluprostenol and IL-1 in cementoblastic cells. METHODS: Confluent OCCM cells were pretreated with the protein synthesis inhibitor cycloheximide followed by fluprostenol or IL-1 for 1.5 hours. cDNA generated from each group was used for cDNA subtraction hybridization to identify differentially induced genes. Preferential gene induction was verified by Northern blot analysis. RESULTS: Thirteen fluprostenol- and seven IL-1-regulated genes were identified. Among the fluprostenol-induced genes was mitogen-activated protein (MAP) kinase phosphatase 1 (MKP1), a negative regulator of MAP kinase signaling. To verify the cDNA subtraction hybridization results, OCCM cells were treated with fluprostenol or prostaglandin F2 (PGF2), and MKP1 mRNA levels were determined. The 0.001 to 1 microM fluprostenol and 0.01 to 1 microM PGF2 significantly induced MKP1 mRNA levels, which peaked at 1 hour of treatment and returned to baseline at 2 hours. CONCLUSIONS: Fluprostenol enhanced, whereas IL-1 inhibited, OCCM mineralization. Using cDNA subtraction hybridization, we identified primary genes that correlate with the observed anabolic and catabolic responses. These findings further our understanding of cementoblast function and suggest that differentially induced genes may mediate cementum formation and resorption.