from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm, mm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, KeepTogether
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont

OUTPUT = "/tmp/workspace/study-guide/Dental_Implant_Failure_Study_Guide_Dr_Shreya.pdf"

# ── Colours ──────────────────────────────────────────────────────────────────
NAVY    = colors.HexColor("#1B3A6B")
TEAL    = colors.HexColor("#0E7A8A")
LTBLUE  = colors.HexColor("#D6EAF8")
LTGREY  = colors.HexColor("#F4F6F7")
MIDGREY = colors.HexColor("#BDC3C7")
WHITE   = colors.white
ACCENT  = colors.HexColor("#E8F4FD")

# ── Document ─────────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=2*cm, rightMargin=2*cm,
    topMargin=2.2*cm, bottomMargin=2*cm,
    title="Why Do Dental Implants Fail? Part I – Study Guide",
    author="Dr. Shreya Chindak",
)

W = A4[0] - 4*cm   # usable width

# ── Styles ───────────────────────────────────────────────────────────────────
base = getSampleStyleSheet()

def S(name, parent="Normal", **kw):
    s = ParagraphStyle(name, parent=base[parent], **kw)
    return s

titleStyle = S("MyTitle", "Title",
    fontSize=22, textColor=NAVY, alignment=TA_CENTER,
    spaceAfter=4, leading=28, fontName="Helvetica-Bold")

subtitleStyle = S("MySubtitle",
    fontSize=11, textColor=TEAL, alignment=TA_CENTER,
    spaceAfter=2, leading=14, fontName="Helvetica-BoldOblique")

authorStyle = S("Author",
    fontSize=12, textColor=NAVY, alignment=TA_CENTER,
    spaceAfter=4, leading=16, fontName="Helvetica-Bold")

refStyle = S("Ref",
    fontSize=8, textColor=colors.HexColor("#7F8C8D"), alignment=TA_CENTER,
    spaceAfter=6, leading=11, fontName="Helvetica-Oblique")

h1Style = S("H1",
    fontSize=13, textColor=WHITE, alignment=TA_LEFT,
    leading=17, fontName="Helvetica-Bold",
    leftIndent=6, spaceAfter=0, spaceBefore=14)

h2Style = S("H2",
    fontSize=11, textColor=NAVY, alignment=TA_LEFT,
    leading=15, fontName="Helvetica-Bold",
    spaceBefore=8, spaceAfter=3, leftIndent=2)

bodyStyle = S("Body",
    fontSize=9.5, textColor=colors.black, alignment=TA_JUSTIFY,
    leading=14, fontName="Helvetica",
    spaceBefore=2, spaceAfter=3, leftIndent=4)

bulletStyle = S("Bullet",
    fontSize=9.5, textColor=colors.black, alignment=TA_LEFT,
    leading=13, fontName="Helvetica",
    leftIndent=16, firstLineIndent=-10,
    spaceBefore=1, spaceAfter=1)

keyStyle = S("Key",
    fontSize=9.2, textColor=colors.HexColor("#1A5276"), alignment=TA_LEFT,
    leading=13, fontName="Helvetica-Bold",
    leftIndent=4, spaceBefore=2, spaceAfter=1)

qStyle = S("Q",
    fontSize=9.5, textColor=NAVY, alignment=TA_LEFT,
    leading=13, fontName="Helvetica-Bold",
    leftIndent=4, spaceBefore=4, spaceAfter=1)

aStyle = S("A",
    fontSize=9.5, textColor=colors.black, alignment=TA_LEFT,
    leading=13, fontName="Helvetica",
    leftIndent=14, spaceBefore=0, spaceAfter=3)

noteStyle = S("Note",
    fontSize=8.8, textColor=colors.HexColor("#7D6608"), alignment=TA_LEFT,
    leading=12, fontName="Helvetica-Oblique",
    leftIndent=6, spaceBefore=2, spaceAfter=4)

smallStyle = S("Small",
    fontSize=8.5, textColor=colors.HexColor("#555555"), alignment=TA_CENTER,
    leading=11, fontName="Helvetica-Oblique")

# ── Helper builders ───────────────────────────────────────────────────────────

def section_header(text):
    """Coloured banner for section headers."""
    tbl = Table([[Paragraph(text, h1Style)]], colWidths=[W])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), NAVY),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING",   (0,0), (-1,-1), 8),
        ("RIGHTPADDING",  (0,0), (-1,-1), 8),
        ("ROUNDEDCORNERS", [4, 4, 4, 4]),
    ]))
    return tbl

def info_table(headers, rows, col_widths, alt_color=LTBLUE):
    data = [[Paragraph(f"<b>{h}</b>", S("TH", fontSize=9, textColor=WHITE,
                        fontName="Helvetica-Bold", leading=12))
             for h in headers]]
    for i, row in enumerate(rows):
        data.append([Paragraph(cell, S(f"TC{i}", fontSize=9, textColor=colors.black,
                                fontName="Helvetica", leading=12, leftIndent=2))
                     for cell in row])
    tbl = Table(data, colWidths=col_widths, repeatRows=1)
    style = [
        ("BACKGROUND",    (0, 0), (-1, 0),  NAVY),
        ("TEXTCOLOR",     (0, 0), (-1, 0),  WHITE),
        ("FONTNAME",      (0, 0), (-1, 0),  "Helvetica-Bold"),
        ("FONTSIZE",      (0, 0), (-1,-1),  9),
        ("ROWBACKGROUNDS",(0, 1), (-1,-1),  [WHITE, alt_color]),
        ("GRID",          (0, 0), (-1,-1),  0.4, MIDGREY),
        ("TOPPADDING",    (0, 0), (-1,-1),  4),
        ("BOTTOMPADDING", (0, 0), (-1,-1),  4),
        ("LEFTPADDING",   (0, 0), (-1,-1),  6),
        ("RIGHTPADDING",  (0, 0), (-1,-1),  6),
        ("VALIGN",        (0, 0), (-1,-1),  "MIDDLE"),
    ]
    tbl.setStyle(TableStyle(style))
    return tbl

def callout(text, bg=ACCENT, border=TEAL):
    """Highlighted callout box."""
    tbl = Table([[Paragraph(text, noteStyle)]], colWidths=[W])
    tbl.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), bg),
        ("TOPPADDING",    (0,0), (-1,-1), 7),
        ("BOTTOMPADDING", (0,0), (-1,-1), 7),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
        ("RIGHTPADDING",  (0,0), (-1,-1), 10),
        ("LINEAFTER",     (0,0), (0,-1),  2, border),
        ("LINEBEFORE",    (0,0), (0,-1),  4, border),
    ]))
    return tbl

def bullet(text):
    return Paragraph(f"&#8226;  {text}", bulletStyle)

def qa(q, a):
    return [Paragraph(f"Q: {q}", qStyle), Paragraph(f"A: {a}", aStyle)]

# ── Build story ───────────────────────────────────────────────────────────────
story = []

# ── COVER / HEADER ────────────────────────────────────────────────────────────
story.append(Spacer(1, 0.3*cm))
story.append(Paragraph("STUDY GUIDE", S("SG", fontSize=10, textColor=TEAL,
    alignment=TA_CENTER, fontName="Helvetica-Bold", spaceAfter=2)))
story.append(HRFlowable(width=W, thickness=2, color=TEAL, spaceAfter=6))
story.append(Paragraph("Why Do Dental Implants Fail? Part I", titleStyle))
story.append(Paragraph(
    "el-Askary AS, Meffert RM, Griffin T &mdash; <i>Implant Dentistry</i>, 1999;8(2):173–185",
    subtitleStyle))
story.append(Spacer(1, 0.15*cm))
story.append(Paragraph("Dr. Shreya Chindak", authorStyle))
story.append(Paragraph("PMID: 10635160", refStyle))
story.append(HRFlowable(width=W, thickness=2, color=TEAL, spaceAfter=10))

# ── 1. PURPOSE ────────────────────────────────────────────────────────────────
story.append(section_header("1.  PURPOSE OF THE ARTICLE"))
story.append(Spacer(1, 4))
for b in [
    "Define what constitutes dental implant <b>failure</b>",
    "Classify failure by <b>etiology, type, and degree</b>",
    "Identify early <b>clinical signs</b> of failure with case examples",
    "Propose a practical <b>Implant Failure Checklist</b> applicable to all implant systems",
    "Outline appropriate <b>management and treatment</b> for each failure category",
]:
    story.append(bullet(b))
story.append(Spacer(1, 6))

# ── 2. CORE DEFINITIONS ───────────────────────────────────────────────────────
story.append(section_header("2.  CORE DEFINITIONS — Know These Cold"))
story.append(Spacer(1, 4))
story.append(info_table(
    ["Term", "Definition", "Salvageable?"],
    [
        ["Ailing Implant",    "Bone loss present but implant still osseointegrated; inflammation present", "Yes — with treatment"],
        ["Failing Implant",   "Progressive bone loss + bleeding on probing + exudate; at imminent risk of loss", "Possibly"],
        ["Failed Implant",    "Complete loss of osseointegration; clinical mobility present", "No — must be removed"],
        ["Surviving Implant", "Still in function with no overt pathology; does NOT equal 'successful'", "N/A"],
    ],
    [3.8*cm, 9.2*cm, 3.2*cm]
))
story.append(Spacer(1, 4))
story.append(callout(
    "Key distinction: 'Surviving' \u2260 'Successful'. A surviving implant simply hasn't been removed. "
    "A successful implant must meet all defined criteria including bone loss thresholds and absence of pathology."
))

# ── 3. CLASSIFICATION ─────────────────────────────────────────────────────────
story.append(section_header("3.  CLASSIFICATION OF FAILURE"))
story.append(Spacer(1, 4))
story.append(Paragraph("By Timing", h2Style))
story.append(info_table(
    ["Type", "When", "Mechanism"],
    [
        ["Early Failure", "Within first 3–4 months (before osseointegration completes)", "Failure OF integration — bone never bonds to implant"],
        ["Late Failure",  "After osseointegration has been established (months–years later)", "Loss OF integration — established bond breaks down"],
    ],
    [3.2*cm, 6.2*cm, 6.8*cm]
))
story.append(Spacer(1, 6))
story.append(Paragraph("By Etiology", h2Style))

# Two-column layout for infective vs non-infective
col1_items = [
    Paragraph("<b>A. Infective (Biologic)</b>", S("ColH", fontSize=10, textColor=TEAL,
        fontName="Helvetica-Bold", leading=14, spaceAfter=3)),
    bullet("Bacterial contamination at surgery"),
    bullet("Pre-existing periodontal disease"),
    bullet("Poor oral hygiene \u2192 peri-implantitis"),
    bullet("Smoking (impaired vascularity &amp; immunity)"),
    bullet("Diabetes mellitus (impaired healing)"),
]
col2_items = [
    Paragraph("<b>B. Non-Infective (Mechanical/Iatrogenic)</b>", S("ColH2", fontSize=10,
        textColor=TEAL, fontName="Helvetica-Bold", leading=14, spaceAfter=3)),
    bullet("Bone overheating during drilling (&gt;47°C / &gt;1 min)"),
    bullet("Inadequate bone quantity or quality"),
    bullet("Premature loading \u2192 micromovement"),
    bullet("Occlusal overload / bruxism"),
    bullet("Poor implant design or component mismatch"),
]

from reportlab.platypus import Frame
tbl2col = Table([[col1_items, col2_items]], colWidths=[W/2 - 3, W/2 - 3])
tbl2col.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (0,-1), colors.HexColor("#EBF5FB")),
    ("BACKGROUND",    (1,0), (1,-1), colors.HexColor("#E8F8F5")),
    ("TOPPADDING",    (0,0), (-1,-1), 8),
    ("BOTTOMPADDING", (0,0), (-1,-1), 8),
    ("LEFTPADDING",   (0,0), (-1,-1), 8),
    ("RIGHTPADDING",  (0,0), (-1,-1), 8),
    ("VALIGN",        (0,0), (-1,-1), "TOP"),
    ("GRID",          (0,0), (-1,-1), 0.5, MIDGREY),
]))
story.append(tbl2col)
story.append(Spacer(1, 6))

# ── 4. RISK FACTORS ───────────────────────────────────────────────────────────
story.append(section_header("4.  RISK FACTORS IN DETAIL"))
story.append(Spacer(1, 4))
story.append(Paragraph("Patient-Related Factors", h2Style))
story.append(info_table(
    ["Risk Factor", "Mechanism of Failure"],
    [
        ["Smoking",          "Vasoconstriction, reduced O\u2082 tension, impaired neutrophil chemotaxis"],
        ["Diabetes mellitus","Microvascular disease, altered collagen metabolism, poor leukocyte function"],
        ["Bruxism",          "Parafunction generates lateral forces exceeding implant biomechanical tolerance"],
        ["Poor oral hygiene","Plaque accumulation \u2192 peri-implant inflammation \u2192 bone loss"],
        ["Bone disease",     "Osteoporosis/osteonecrosis reduce bone-to-implant contact (BIC)"],
    ],
    [4.2*cm, 12*cm]
))
story.append(Spacer(1, 5))
story.append(Paragraph("Surgical Factors", h2Style))
story.append(info_table(
    ["Factor", "Consequence"],
    [
        ["Bone overheating (&gt;47°C for &gt;1 min)", "Thermal necrosis \u2192 fibrous encapsulation instead of osseointegration"],
        ["Contaminated implant surface",              "Disrupts titanium oxide layer; promotes early biofilm colonisation"],
        ["Incorrect positioning",                     "Biomechanical stress concentration; esthetic and functional compromise"],
        ["Inadequate primary stability",              "Micromovement during healing \u2192 fibrous interface instead of bone-implant bond"],
    ],
    [5.8*cm, 10.4*cm]
))
story.append(Spacer(1, 5))
story.append(Paragraph("Restorative Factors", h2Style))
for b in [
    "Premature loading before osseointegration is complete",
    "Excessive cantilever length \u2192 off-axis forces",
    "Poorly fitting prosthetic components (gaps allow bacterial colonisation)",
    "Occlusal discrepancies generating non-axial forces on the implant",
]:
    story.append(bullet(b))
story.append(Spacer(1, 6))

# ── 5. FAILURE CHECKLIST ──────────────────────────────────────────────────────
story.append(section_header("5.  THE IMPLANT FAILURE CHECKLIST"))
story.append(Spacer(1, 4))
story.append(bodyStyle and Paragraph(
    "The authors' major practical contribution — a structured, <b>system-independent</b> diagnostic tool "
    "to guide clinicians in identifying the cause and severity of any implant failure:", bodyStyle))
story.append(Spacer(1, 4))
checklist_items = [
    ("1", "Is the failure <b>infective</b> or <b>non-infective</b>?"),
    ("2", "At what <b>phase</b> did failure occur? (Surgical vs. Restorative)"),
    ("3", "Which <b>factors or personnel</b> are responsible?"),
    ("4", "What is the <b>degree of bone loss</b>?"),
    ("5", "Is the implant <b>ailing, failing, or failed</b>?"),
    ("6", "What <b>repair or salvage procedures</b> are indicated?"),
]
cl_data = [[Paragraph(f"<b>{n}</b>", S("CLN", fontSize=11, textColor=WHITE, fontName="Helvetica-Bold",
                alignment=TA_CENTER, leading=14)),
            Paragraph(t, S("CLT", fontSize=9.5, textColor=colors.black, fontName="Helvetica",
                leading=13, leftIndent=2))]
           for n, t in checklist_items]
cl_tbl = Table(cl_data, colWidths=[1.0*cm, W - 1.4*cm])
cl_tbl.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (0,-1), TEAL),
    ("BACKGROUND",    (1,0), (1,-1), LTGREY),
    ("ROWBACKGROUNDS",(1,0), (1,-1), [WHITE, LTGREY]),
    ("TOPPADDING",    (0,0), (-1,-1), 5),
    ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 8),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("GRID",          (0,0), (-1,-1), 0.4, MIDGREY),
]))
story.append(cl_tbl)
story.append(Spacer(1, 6))

# ── 6. CLINICAL SIGNS ─────────────────────────────────────────────────────────
story.append(section_header("6.  CLINICAL SIGNS OF FAILURE"))
story.append(Spacer(1, 4))
signs = [
    ("<b>Mobility</b>", "ALWAYS pathological — any implant mobility = failure; most reliable single sign"),
    ("<b>Pain</b>", "Pain on function or percussion suggests loss of integration or infection"),
    ("<b>Radiolucency</b>", "Peri-implant radiolucency on radiograph indicates bone-implant separation"),
    ("<b>Bone loss</b>", "&gt;1.5 mm in year 1 or &gt;0.2 mm/year thereafter exceeds Albrektsson criteria"),
    ("<b>Exudate</b>", "Suppuration or exudate from the peri-implant sulcus indicates infection"),
    ("<b>Probing depth</b>", "Depth &gt;5–6 mm with bleeding on probing is a warning sign"),
]
story.append(info_table(
    ["Sign", "Clinical Significance"],
    signs,
    [3.8*cm, 12.4*cm]
))
story.append(Spacer(1, 6))

# ── 7. DISEASE PROGRESSION ────────────────────────────────────────────────────
story.append(section_header("7.  PERI-IMPLANT DISEASE PROGRESSION"))
story.append(Spacer(1, 5))
prog_data = [
    ["Plaque Accumulation", "\u2192", "Peri-implant Mucositis", "\u2192", "Peri-implantitis", "\u2192", "Ailing \u2192 Failing \u2192 Failed"],
    ["Biofilm forms on implant surface", "", "Soft tissue only; REVERSIBLE", "", "Bone loss begins; NOT reversible", "", "Progressive loss of osseointegration"],
]
p_styles = [
    S("PB", fontSize=9, textColor=WHITE, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=12),
    S("PA", fontSize=13, textColor=TEAL, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=14),
    S("PB2", fontSize=9, textColor=WHITE, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=12),
    S("PA2", fontSize=13, textColor=TEAL, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=14),
    S("PB3", fontSize=9, textColor=WHITE, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=12),
    S("PA3", fontSize=13, textColor=TEAL, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=14),
    S("PB4", fontSize=8.5, textColor=WHITE, fontName="Helvetica-Bold", alignment=TA_CENTER, leading=11),
]
sub_styles = [
    S("PS", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS2", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS3", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS4", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS5", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS6", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
    S("PS7", fontSize=7.5, textColor=colors.HexColor("#888"), fontName="Helvetica-Oblique", alignment=TA_CENTER, leading=10),
]

col_w = [3.5*cm, 0.5*cm, 3.5*cm, 0.5*cm, 3.5*cm, 0.5*cm, 4.7*cm]
row0 = [Paragraph(prog_data[0][i], p_styles[i]) for i in range(7)]
row1 = [Paragraph(prog_data[1][i], sub_styles[i]) for i in range(7)]
prog_tbl = Table([row0, row1], colWidths=col_w)
prog_tbl.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (0,1), colors.HexColor("#2ECC71")),
    ("BACKGROUND",    (2,0), (2,1), colors.HexColor("#F39C12")),
    ("BACKGROUND",    (4,0), (4,1), colors.HexColor("#E74C3C")),
    ("BACKGROUND",    (6,0), (6,1), colors.HexColor("#8E44AD")),
    ("TOPPADDING",    (0,0), (-1,-1), 5),
    ("BOTTOMPADDING", (0,0), (-1,-1), 3),
    ("LEFTPADDING",   (0,0), (-1,-1), 4),
    ("RIGHTPADDING",  (0,0), (-1,-1), 4),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
]))
story.append(prog_tbl)
story.append(Spacer(1, 6))

# ── 8. SUCCESS CRITERIA ───────────────────────────────────────────────────────
story.append(section_header("8.  SUCCESS CRITERIA (Albrektsson et al.)"))
story.append(Spacer(1, 4))
story.append(bodyStyle and Paragraph(
    "An implant is classified as <b>successful</b> only if ALL criteria are met:", bodyStyle))
story.append(Spacer(1, 3))
for b in [
    "No clinical mobility when tested independently",
    "No peri-implant radiolucency on undistorted radiograph",
    "Bone loss &lt;1.5 mm in the first year; &lt;0.2 mm/year thereafter",
    "No persistent pain, infection, neuropathy, paresthesia, or damage to adjacent structures",
    "5-year cumulative success rate \u2265 85%; 10-year rate \u2265 80%",
]:
    story.append(bullet(b))
story.append(Spacer(1, 6))

# ── 9. MANAGEMENT ─────────────────────────────────────────────────────────────
story.append(section_header("9.  MANAGEMENT BY IMPLANT STATUS"))
story.append(Spacer(1, 4))
story.append(info_table(
    ["Status", "Key Interventions"],
    [
        ["AILING",   "Debridement of peri-implant pocket; chlorhexidine irrigation; systemic antibiotics if indicated; "
                     "surface decontamination (citric acid / air-powder abrasive); oral hygiene reinforcement"],
        ["FAILING",  "Surgical debridement; guided bone regeneration (GBR) if defect morphology is favourable; "
                     "address and eliminate systemic/local risk factors; close monitoring — aim to convert to 'ailing'"],
        ["FAILED",   "Remove implant; allow 3–6 months healing; resolve causative factors; bone graft if significant "
                     "defect remains; reassess and consider re-implantation when site is stable"],
    ],
    [2.4*cm, 13.8*cm],
    alt_color=colors.HexColor("#FDFEFE")
))
story.append(Spacer(1, 6))

# ── 10. HIGH-YIELD Q&A ────────────────────────────────────────────────────────
story.append(section_header("10.  HIGH-YIELD EXAM Q&A"))
story.append(Spacer(1, 4))

qas = [
    ("What temperature causes thermal bone necrosis during implant drilling?",
     "Above 47°C sustained for more than 1 minute causes irreversible thermal necrosis of bone."),
    ("What is the difference between peri-implant mucositis and peri-implantitis?",
     "Mucositis = reversible inflammation confined to soft tissue only. "
     "Peri-implantitis = involves progressive bone destruction; not fully reversible."),
    ("Name the four categories of implant status used by el-Askary et al.",
     "Ailing, Failing, Failed, Surviving."),
    ("What is the most reliable clinical sign of implant failure?",
     "Mobility — any implant mobility (however slight) indicates failure or absence of osseointegration."),
    ("When is an implant classified as an 'early failure'?",
     "When integration is lost before osseointegration is established — typically within the first 3–4 months post-placement."),
    ("What is the key difference between 'surviving' and 'successful'?",
     "A surviving implant is simply still in function. A successful implant must meet all defined criteria "
     "(bone loss limits, no pathology, cumulative success rate thresholds)."),
    ("Name the top systemic risk factors for implant failure.",
     "Diabetes mellitus, smoking, bruxism, and metabolic bone disease."),
    ("What is the significance of the Implant Failure Checklist?",
     "It is system-independent (works for any brand/design) and guides the clinician in determining "
     "whether failure is infective vs. non-infective and at what phase it occurred."),
]

for q, a in qas:
    items = qa(q, a)
    story.extend(items)

story.append(Spacer(1, 6))

# ── 11. PART I vs PART II ─────────────────────────────────────────────────────
story.append(section_header("11.  PART I vs. PART II — How They Fit Together"))
story.append(Spacer(1, 4))
story.append(info_table(
    ["Part I (this article)", "Part II (same authors, 1999)"],
    [
        ["Defines failure terminology (ailing/failing/failed/surviving)",
         "Expands classification: failure mode, type, origin, timing"],
        ["Infective vs. non-infective etiology",
         "Classification by responsible personnel and tissue type"],
        ["Proposes the Implant Failure Checklist",
         "More detailed clinical management algorithms"],
        ["Highlights early clinical signs with case examples",
         "Covers salvage and re-treatment strategies in depth"],
    ],
    [W/2 - 2, W/2 - 2]
))
story.append(Spacer(1, 6))

# ── 12. ONE-PAGE SUMMARY ──────────────────────────────────────────────────────
story.append(section_header("12.  ONE-SENTENCE SUMMARY"))
story.append(Spacer(1, 4))
story.append(callout(
    "Implant failure is multifactorial and classifiable — understanding WHEN (early vs. late), "
    "WHY (infective vs. non-infective), and HOW SEVERELY (ailing vs. failing vs. failed) an implant "
    "fails allows the clinician to make rational, evidence-based treatment decisions, guided by the "
    "authors' system-independent Implant Failure Checklist.",
    bg=colors.HexColor("#EAF2FF"), border=NAVY
))
story.append(Spacer(1, 8))

# ── Footer reference ──────────────────────────────────────────────────────────
story.append(HRFlowable(width=W, thickness=1, color=MIDGREY, spaceAfter=5))
story.append(Paragraph(
    "el Askary AS, Meffert RM, Griffin T. Why do dental implants fail? Part I. "
    "<i>Implant Dent.</i> 1999;8(2):173–185.  |  PMID: 10635160",
    smallStyle))

# ── Build ─────────────────────────────────────────────────────────────────────
doc.build(story)
print(f"PDF created: {OUTPUT}")